コード例 #1
0
    def test_ComplexSuperApply(self):
        """
        Superoperator: Efficient numerics and reference return same result,
        acting on non-composite system
        """
        rho_list = list(map(rand_dm, [2, 3, 2, 3, 2]))
        rho_input = tensor(rho_list)
        superop = kraus_to_super(rand_kraus_map(3))

        analytic_result = rho_list
        analytic_result[1] = Qobj(vec2mat(superop.data.todense() *
                                  mat2vec(analytic_result[1].data.todense())))
        analytic_result[3] = Qobj(vec2mat(superop.data.todense() *
                                  mat2vec(analytic_result[3].data.todense())))
        analytic_result = tensor(analytic_result)

        naive_result = subsystem_apply(rho_input, superop,
                                       [False, True, False, True, False],
                                       reference=True)
        naive_diff = (analytic_result - naive_result).data.todense()
        assert_(norm(naive_diff) < 1e-12)

        efficient_result = subsystem_apply(rho_input, superop,
                                           [False, True, False, True, False])
        efficient_diff = (efficient_result - analytic_result).data.todense()
        assert_(norm(efficient_diff) < 1e-12)
コード例 #2
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def qpt(U, op_basis_list):
    """
    Calculate the quantum process tomography chi matrix for a given 
    (possibly nonunitary) transformation matrix U, which transforms a 
    density matrix in vector form according to:

        vec(rho) = U * vec(rho0)

        or

        rho = vec2mat(U * mat2vec(rho0))

    U can be calculated for an open quantum system using the QuTiP propagator
    function.
    """

    E_ops = []
    # loop over all index permutations
    for inds in index_permutations([len(op_list) for op_list in op_basis_list]):
        # loop over all composite systems
        E_op_list = [op_basis_list[k][inds[k]] for k in range(len(op_basis_list))]
        E_ops.append(tensor(E_op_list))

    EE_ops = [spre(E1) * spost(E2.dag()) for E1 in E_ops for E2 in E_ops]

    M = hstack([mat2vec(EE.full()) for EE in EE_ops])

    Uvec = mat2vec(U.full())

    chi_vec = la.solve(M, Uvec)

    return vec2mat(chi_vec)
コード例 #3
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    def test_ComplexSuperApply(self):
        """
        Superoperator: Efficient numerics and reference return same result,
        acting on non-composite system
        """
        tol = 1e-10
        rho_list = list(map(rand_dm, [2, 3, 2, 3, 2]))
        rho_input = tensor(rho_list)
        superop = kraus_to_super(rand_kraus_map(3))

        analytic_result = rho_list
        analytic_result[1] = Qobj(
            vec2mat(superop.full() @ mat2vec(analytic_result[1].full())))
        analytic_result[3] = Qobj(
            vec2mat(superop.full() @ mat2vec(analytic_result[3].full())))
        analytic_result = tensor(analytic_result)

        naive_result = subsystem_apply(rho_input,
                                       superop,
                                       [False, True, False, True, False],
                                       reference=True)
        naive_diff = (analytic_result - naive_result).full()
        naive_diff_norm = norm(naive_diff)
        assert_(naive_diff_norm < tol,
                msg="ComplexSuper: naive_diff_norm {} "
                "is beyond tolerance {}".format(naive_diff_norm, tol))

        efficient_result = subsystem_apply(rho_input, superop,
                                           [False, True, False, True, False])
        efficient_diff = (efficient_result - analytic_result).full()
        efficient_diff_norm = norm(efficient_diff)
        assert_(efficient_diff_norm < tol,
                msg="ComplexSuper: efficient_diff_norm {} "
                "is beyond tolerance {}".format(efficient_diff_norm, tol))
コード例 #4
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ファイル: qpt.py プロジェクト: Shuangshuang/qutip-doc
def qpt(U, op_basis_list):
    """
    Calculate the quantum process tomography chi matrix for a given 
    (possibly nonunitary) transformation matrix U, which transforms a 
    density matrix in vector form according to:

        vec(rho) = U * vec(rho0)

        or

        rho = vec2mat(U * mat2vec(rho0))

    U can be calculated for an open quantum system using the QuTiP propagator
    function.
    """

    E_ops = []
    # loop over all index permutations
    for inds in index_permutations([len(op_list) for op_list in op_basis_list]):
        # loop over all composite systems
        E_op_list = [op_basis_list[k][inds[k]] for k in range(len(op_basis_list))]
        E_ops.append(tensor(E_op_list))

    EE_ops = [spre(E1) * spost(E2.dag()) for E1 in E_ops for E2 in E_ops]

    M = hstack([mat2vec(EE.full()) for EE in EE_ops])

    Uvec = mat2vec(U.full())

    chi_vec = la.solve(M, Uvec)

    return vec2mat(chi_vec)
コード例 #5
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ファイル: test_subsys_apply.py プロジェクト: yipk2/qutip
    def test_ComplexSuperApply(self):
        """
        Superoperator: Efficient numerics and reference return same result,
        acting on non-composite system
        """
        rho_list = list(map(rand_dm, [2, 3, 2, 3, 2]))
        rho_input = tensor(rho_list)
        superop = kraus_to_super(rand_kraus_map(3))

        analytic_result = rho_list
        analytic_result[1] = Qobj(
            vec2mat(superop.data.todense() *
                    mat2vec(analytic_result[1].data.todense())))
        analytic_result[3] = Qobj(
            vec2mat(superop.data.todense() *
                    mat2vec(analytic_result[3].data.todense())))
        analytic_result = tensor(analytic_result)

        naive_result = subsystem_apply(rho_input,
                                       superop,
                                       [False, True, False, True, False],
                                       reference=True)
        naive_diff = (analytic_result - naive_result).data.todense()
        assert_(norm(naive_diff) < 1e-12)

        efficient_result = subsystem_apply(rho_input, superop,
                                           [False, True, False, True, False])
        efficient_diff = (efficient_result - analytic_result).data.todense()
        assert_(norm(efficient_diff) < 1e-12)
コード例 #6
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ファイル: test_brtools.py プロジェクト: NunoEdgarGub1/qutip
def test_vec_to_eigbasis():
    "BR Tools : vector to eigenbasis"
    N = 10
    for kk in range(50):
        H = rand_herm(N,0.5)
        h = H.full('F')
        R = rand_dm(N,0.5)
        r = mat2vec(R.full()).ravel()
        ans = mat2vec(R.transform(H.eigenstates()[1]).full()).ravel()
        out = _test_vec_to_eigbasis(h, r)
        assert_(np.allclose(ans,out))
コード例 #7
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def test_vec_to_eigbasis():
    "BR Tools : vector to eigenbasis"
    N = 10
    for kk in range(50):
        H = rand_herm(N, 0.5)
        h = H.full('F')
        R = rand_dm(N, 0.5)
        r = mat2vec(R.full()).ravel()
        ans = mat2vec(R.transform(H.eigenstates()[1]).full()).ravel()
        out = _test_vec_to_eigbasis(h, r)
        assert_(np.allclose(ans, out))
コード例 #8
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ファイル: test_brtools.py プロジェクト: NunoEdgarGub1/qutip
def test_eigvec_to_fockbasis():
    "BR Tools : eigvector to fockbasis"
    N = 10
    for kk in range(50):
        H = rand_herm(N,0.5)
        h = H.full('F')
        R = rand_dm(N,0.5)
        r = mat2vec(R.full()).ravel()
        eigvals = np.zeros(N,dtype=float)
        Z = _test_zheevr(H.full('F'), eigvals)
        eig_vec = mat2vec(R.transform(H.eigenstates()[1]).full()).ravel()
        out = _test_eigvec_to_fockbasis(eig_vec, Z, N)
        assert_(np.allclose(r,out))
コード例 #9
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def test_eigvec_to_fockbasis():
    "BR Tools : eigvector to fockbasis"
    N = 10
    for kk in range(50):
        H = rand_herm(N, 0.5)
        h = H.full('F')
        R = rand_dm(N, 0.5)
        r = mat2vec(R.full()).ravel()
        eigvals = np.zeros(N, dtype=float)
        Z = _test_zheevr(H.full('F'), eigvals)
        eig_vec = mat2vec(R.transform(H.eigenstates()[1]).full()).ravel()
        out = _test_eigvec_to_fockbasis(eig_vec, Z, N)
        assert_(np.allclose(r, out))
コード例 #10
0
ファイル: stochastic.py プロジェクト: lmessio/qutip
def smepdpsolve_generic(ssdata, options, progress_bar):
    """
    For internal use.

    .. note::

        Experimental.

    """
    if debug:
        print(inspect.stack()[0][3])

    N_store = len(ssdata.tlist)
    N_substeps = ssdata.nsubsteps
    N = N_store * N_substeps
    dt = (ssdata.tlist[1] - ssdata.tlist[0]) / N_substeps
    NT = ssdata.ntraj

    data = Odedata()
    data.solver = "smepdpsolve"
    data.times = ssdata.tlist
    data.expect = np.zeros((len(ssdata.e_ops), N_store), dtype=complex)
    data.jump_times = []
    data.jump_op_idx = []

    # Liouvillian for the deterministic part.
    # needs to be modified for TD systems
    L = liouvillian_fast(ssdata.H, ssdata.c_ops)
        
    progress_bar.start(ssdata.ntraj)

    for n in range(ssdata.ntraj):
        progress_bar.update(n)
        rho_t = mat2vec(ssdata.rho0.full()).ravel()

        states_list, jump_times, jump_op_idx = \
            _smepdpsolve_single_trajectory(data, L, dt, ssdata.tlist,
                                           N_store, N_substeps,
                                           rho_t, ssdata.c_ops, ssdata.e_ops)

        data.states.append(states_list)
        data.jump_times.append(jump_times)
        data.jump_op_idx.append(jump_op_idx)

    progress_bar.finished()

    # average density matrices
    if options.average_states and np.any(data.states):
        data.states = [sum(state_list).unit() for state_list in data.states]
    
    # average
    data.expect = data.expect / ssdata.ntraj

    # standard error
    if NT > 1:
        data.se = (data.ss - NT * (data.expect ** 2)) / (NT * (NT - 1))
    else:
        data.se = None

    return data
コード例 #11
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 def _initialize_data(self, L, rho, dt, c_ops, backwards):
     L_list = []
     control_indices = []
     if not (c_ops is None or len(c_ops) == 0):
         # in principle, we could convert c_ops to a Lindbladian, here
         raise NotImplementedError("c_ops not implemented")
     for (i, spec) in enumerate(L):
         if isinstance(spec, qutip.Qobj):
             l_op = spec
             l_coeff = 1
         elif isinstance(spec, list) and isinstance(spec[0], qutip.Qobj):
             l_op = spec[0]
             l_coeff = spec[1]
             control_indices.append(i)
         else:
             raise ValueError(
                 "Incorrect specification of time-dependent Liouvillian")
         if l_op.type == 'super':
             L_list.append([l_op.data, l_coeff, False])
         else:
             raise ValueError(
                 "Incorrect specification of time-dependent Liouvillian")
     self._L_list = L_list
     self._control_indices = control_indices
     if rho.type == 'oper':
         self._y = mat2vec(rho.full()).ravel('F')  # initial state
     else:
         raise ValueError("rho must be a density matrix")
コード例 #12
0
ファイル: stochastic.py プロジェクト: markusbaden/qutip
def smesolve_generic(H, rho0, tlist, c_ops, sc_ops, e_ops,
                     rhs, d1, d2, d2_len, ntraj, nsubsteps,
                     options, progress_bar):
    """
    internal

    .. note::

        Experimental.

    """
    if debug:
        print(inspect.stack()[0][3])

    N_store = len(tlist)
    N_substeps = nsubsteps
    N = N_store * N_substeps
    dt = (tlist[1] - tlist[0]) / N_substeps

    data = Odedata()
    data.solver = "smesolve"
    data.times = tlist
    data.expect = np.zeros((len(e_ops), N_store), dtype=complex)

    # pre-compute collapse operator combinations that are commonly needed
    # when evaluating the RHS of stochastic master equations
    A_ops = []
    for c_idx, c in enumerate(sc_ops):

        # xxx: precompute useful operator expressions...
        cdc = c.dag() * c
        Ldt = spre(c) * spost(c.dag()) - 0.5 * spre(cdc) - 0.5 * spost(cdc)
        LdW = spre(c) + spost(c.dag())
        Lm = spre(c) + spost(c.dag())  # currently same as LdW

        A_ops.append([Ldt.data, LdW.data, Lm.data])

    # Liouvillian for the deterministic part
    L = liouvillian_fast(H, c_ops)  # needs to be modified for TD systems

    progress_bar.start(ntraj)

    for n in range(ntraj):
        progress_bar.update(n)

        rho_t = mat2vec(rho0.full())

        states_list = _smesolve_single_trajectory(
            L, dt, tlist, N_store, N_substeps,
            rho_t, A_ops, e_ops, data, rhs, d1, d2, d2_len)

        # if average -> average...
        data.states.append(states_list)

    progress_bar.finished()

    # average
    data.expect = data.expect / ntraj

    return data
コード例 #13
0
ファイル: stochastic.py プロジェクト: partus/qutip
def smesolve_generic(H, rho0, tlist, c_ops, e_ops, rhs, d1, d2, ntraj, nsubsteps):
    """
    internal

    .. note::

        Experimental.

    """
    if debug:
        print(inspect.stack()[0][3])

    N_store = len(tlist)
    N_substeps = nsubsteps
    N = N_store * N_substeps
    dt = (tlist[1] - tlist[0]) / N_substeps

    print("N = %d. dt=%.2e" % (N, dt))

    data = Odedata()

    data.expect = np.zeros((len(e_ops), N_store), dtype=complex)

    # pre-compute collapse operator combinations that are commonly needed
    # when evaluating the RHS of stochastic master equations
    A_ops = []
    for c_idx, c in enumerate(c_ops):

        # xxx: precompute useful operator expressions...
        cdc = c.dag() * c
        Ldt = spre(c) * spost(c.dag()) - 0.5 * spre(cdc) - 0.5 * spost(cdc)
        LdW = spre(c) + spost(c.dag())
        Lm = spre(c) + spost(c.dag())  # currently same as LdW

        A_ops.append([Ldt.data, LdW.data, Lm.data])

    # Liouvillian for the unitary part
    L = -1.0j * (spre(H) - spost(H))  # XXX: should we split the ME in stochastic
    # and deterministic collapse operators here?

    progress_acc = 0.0
    for n in range(ntraj):

        if debug and (100 * float(n) / ntraj) >= progress_acc:
            print("Progress: %.2f" % (100 * float(n) / ntraj))
            progress_acc += 10.0

        rho_t = mat2vec(rho0.full())

        states_list = _smesolve_single_trajectory(
            L, dt, tlist, N_store, N_substeps, rho_t, A_ops, e_ops, data, rhs, d1, d2
        )

        # if average -> average...
        data.states.append(states_list)

    # average
    data.expect = data.expect / ntraj

    return data
コード例 #14
0
ファイル: mesolve.py プロジェクト: NunoEdgarGub1/qutip
def _mesolve_const(H, rho0, tlist, c_op_list, e_ops, args, opt,
                   progress_bar):
    """
    Evolve the density matrix using an ODE solver, for constant hamiltonian
    and collapse operators.
    """

    if debug:
        print(inspect.stack()[0][3])

    #
    # check initial state
    #
    if isket(rho0):
        # if initial state is a ket and no collapse operator where given,
        # fall back on the unitary schrodinger equation solver
        if len(c_op_list) == 0 and isoper(H):
            return _sesolve_const(H, rho0, tlist, e_ops, args, opt,
                                  progress_bar)

        # Got a wave function as initial state: convert to density matrix.
        rho0 = ket2dm(rho0)

    #
    # construct liouvillian
    #
    if opt.tidy:
        H = H.tidyup(opt.atol)

    L = liouvillian(H, c_op_list)
    

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full()).ravel('F')
    if issuper(rho0):
        r = scipy.integrate.ode(_ode_super_func)
        r.set_f_params(L.data)
    else:
        if opt.use_openmp and L.data.nnz >= qset.openmp_thresh:
            r = scipy.integrate.ode(cy_ode_rhs_openmp)
            r.set_f_params(L.data.data, L.data.indices, L.data.indptr, 
                            opt.openmp_threads)
        else:
            r = scipy.integrate.ode(cy_ode_rhs)
            r.set_f_params(L.data.data, L.data.indices, L.data.indptr)
        # r = scipy.integrate.ode(_ode_rho_test)
        # r.set_f_params(L.data)
    r.set_integrator('zvode', method=opt.method, order=opt.order,
                     atol=opt.atol, rtol=opt.rtol, nsteps=opt.nsteps,
                     first_step=opt.first_step, min_step=opt.min_step,
                     max_step=opt.max_step)
    r.set_initial_value(initial_vector, tlist[0])

    #
    # call generic ODE code
    #
    return _generic_ode_solve(r, rho0, tlist, e_ops, opt, progress_bar)
コード例 #15
0
def _smepdpsolve_generic(sso, options, progress_bar):
    """
    For internal use. See smepdpsolve.
    """
    if debug:
        logger.debug(inspect.stack()[0][3])

    N_store = len(sso.times)
    N_substeps = sso.nsubsteps
    dt = (sso.times[1] - sso.times[0]) / N_substeps
    nt = sso.ntraj

    data = Result()
    data.solver = "smepdpsolve"
    data.times = sso.times
    data.expect = np.zeros((len(sso.e_ops), N_store), dtype=complex)
    data.jump_times = []
    data.jump_op_idx = []

    # Liouvillian for the deterministic part.
    # needs to be modified for TD systems
    L = liouvillian(sso.H, sso.c_ops)

    progress_bar.start(sso.ntraj)

    for n in range(sso.ntraj):
        progress_bar.update(n)
        rho_t = mat2vec(sso.rho0.full()).ravel()

        states_list, jump_times, jump_op_idx = \
            _smepdpsolve_single_trajectory(data, L, dt, sso.times,
                                           N_store, N_substeps,
                                           rho_t, sso.rho0.dims,
                                           sso.c_ops, sso.e_ops)

        data.states.append(states_list)
        data.jump_times.append(jump_times)
        data.jump_op_idx.append(jump_op_idx)

    progress_bar.finished()

    # average density matrices
    if options.average_states and np.any(data.states):
        data.states = [
            sum([data.states[m][n] for m in range(nt)]).unit()
            for n in range(len(data.times))
        ]

    # average
    data.expect = data.expect / sso.ntraj

    # standard error
    if nt > 1:
        data.se = (data.ss - nt * (data.expect**2)) / (nt * (nt - 1))
    else:
        data.se = None

    return data
コード例 #16
0
ファイル: mesolve.py プロジェクト: mothaibatacungmua/qutip
def _mesolve_const(H, rho0, tlist, c_op_list, e_ops, args, opt, progress_bar):
    """
    Evolve the density matrix using an ODE solver, for constant hamiltonian
    and collapse operators.
    """

    if debug:
        print(inspect.stack()[0][3])

    #
    # check initial state
    #
    if isket(rho0):
        # if initial state is a ket and no collapse operator where given,
        # fall back on the unitary schrodinger equation solver
        if len(c_op_list) == 0 and isoper(H):
            return _sesolve_const(H, rho0, tlist, e_ops, args, opt,
                                  progress_bar)

        # Got a wave function as initial state: convert to density matrix.
        rho0 = ket2dm(rho0)

    #
    # construct liouvillian
    #
    if opt.tidy:
        H = H.tidyup(opt.atol)

    L = liouvillian(H, c_op_list)

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full()).ravel('F')
    if issuper(rho0):
        r = scipy.integrate.ode(_ode_super_func)
        r.set_f_params(L.data)
    else:
        r = scipy.integrate.ode(cy_ode_rhs)
        r.set_f_params(L.data.data, L.data.indices, L.data.indptr)
        # r = scipy.integrate.ode(_ode_rho_test)
        # r.set_f_params(L.data)
    r.set_integrator('zvode',
                     method=opt.method,
                     order=opt.order,
                     atol=opt.atol,
                     rtol=opt.rtol,
                     nsteps=opt.nsteps,
                     first_step=opt.first_step,
                     min_step=opt.min_step,
                     max_step=opt.max_step)
    r.set_initial_value(initial_vector, tlist[0])

    #
    # call generic ODE code
    #
    return _generic_ode_solve(r, rho0, tlist, e_ops, opt, progress_bar)
コード例 #17
0
ファイル: pdpsolve.py プロジェクト: sahmed95/qutip
def _smepdpsolve_generic(sso, options, progress_bar):
    """
    For internal use. See smepdpsolve.
    """
    if debug:
        logger.debug(inspect.stack()[0][3])

    N_store = len(sso.times)
    N_substeps = sso.nsubsteps
    dt = (sso.times[1] - sso.times[0]) / N_substeps
    nt = sso.ntraj

    data = Result()
    data.solver = "smepdpsolve"
    data.times = sso.times
    data.expect = np.zeros((len(sso.e_ops), N_store), dtype=complex)
    data.jump_times = []
    data.jump_op_idx = []

    # Liouvillian for the deterministic part.
    # needs to be modified for TD systems
    L = liouvillian(sso.H, sso.c_ops)

    progress_bar.start(sso.ntraj)

    for n in range(sso.ntraj):
        progress_bar.update(n)
        rho_t = mat2vec(sso.rho0.full()).ravel()

        states_list, jump_times, jump_op_idx = \
            _smepdpsolve_single_trajectory(data, L, dt, sso.times,
                                           N_store, N_substeps,
                                           rho_t, sso.rho0.dims,
                                           sso.c_ops, sso.e_ops)

        data.states.append(states_list)
        data.jump_times.append(jump_times)
        data.jump_op_idx.append(jump_op_idx)

    progress_bar.finished()

    # average density matrices
    if options.average_states and np.any(data.states):
        data.states = [sum([data.states[m][n] for m in range(nt)]).unit()
                       for n in range(len(data.times))]

    # average
    data.expect = data.expect / sso.ntraj

    # standard error
    if nt > 1:
        data.se = (data.ss - nt * (data.expect ** 2)) / (nt * (nt - 1))
    else:
        data.se = None

    return data
コード例 #18
0
def test_vector_roundtrip():
    "BR Tools : vector roundtrip transform"
    N = 10
    for kk in range(50):
        H = rand_herm(N, 0.5)
        h = H.full('F')
        R = rand_dm(N, 0.5)
        r = mat2vec(R.full()).ravel()
        out = _test_vector_roundtrip(h, r)
        assert_(np.allclose(r, out))
コード例 #19
0
ファイル: test_brtools.py プロジェクト: NunoEdgarGub1/qutip
def test_vector_roundtrip():
    "BR Tools : vector roundtrip transform"
    N = 10
    for kk in range(50):
        H = rand_herm(N,0.5)
        h = H.full('F')
        R = rand_dm(N,0.5)
        r = mat2vec(R.full()).ravel()
        out = _test_vector_roundtrip(h,r)
        assert_(np.allclose(r,out))
コード例 #20
0
ファイル: countstat.py プロジェクト: NunoEdgarGub1/qutip
def countstat_current(L, c_ops=None, rhoss=None, J_ops=None):
    """
    Calculate the current corresponding a system Liouvillian `L` and a list of
    current collapse operators `c_ops` or current superoperators `J_ops`
    (either must be specified). Optionally the steadystate density matrix
    `rhoss` and a list of current superoperators `J_ops` can be specified. If
    either of these are omitted they are computed internally.

    Parameters
    ----------

    L : :class:`qutip.Qobj`
        Qobj representing the system Liouvillian.

    c_ops : array / list (optional)
        List of current collapse operators.

    rhoss : :class:`qutip.Qobj` (optional)
        The steadystate density matrix corresponding the system Liouvillian
        `L`.

    J_ops : array / list (optional)
        List of current superoperators.

    Returns
    --------
    I : array
        The currents `I` corresponding to each current collapse operator
        `c_ops` (or, equivalently, each current superopeator `J_ops`).
    """

    if J_ops is None:
        if c_ops is None:
            raise ValueError("c_ops must be given if J_ops is not")
        J_ops = [sprepost(c, c.dag()) for c in c_ops]

    if rhoss is None:
        if c_ops is None:
            raise ValueError("c_ops must be given if rhoss is not")
        rhoss = steadystate(L, c_ops)

    rhoss_vec = mat2vec(rhoss.full()).ravel()

    N = len(J_ops)
    I = np.zeros(N)

    for i, Ji in enumerate(J_ops):
        I[i] = expect_rho_vec(Ji.data, rhoss_vec, 1)

    return I
コード例 #21
0
ファイル: countstat.py プロジェクト: zzpwahaha/qutip
def countstat_current(L, c_ops=None, rhoss=None, J_ops=None):
    """
    Calculate the current corresponding a system Liouvillian `L` and a list of
    current collapse operators `c_ops` or current superoperators `J_ops`
    (either must be specified). Optionally the steadystate density matrix
    `rhoss` and a list of current superoperators `J_ops` can be specified. If
    either of these are omitted they are computed internally.

    Parameters
    ----------

    L : :class:`qutip.Qobj`
        Qobj representing the system Liouvillian.

    c_ops : array / list (optional)
        List of current collapse operators.

    rhoss : :class:`qutip.Qobj` (optional)
        The steadystate density matrix corresponding the system Liouvillian
        `L`.

    J_ops : array / list (optional)
        List of current superoperators.

    Returns
    --------
    I : array
        The currents `I` corresponding to each current collapse operator
        `c_ops` (or, equivalently, each current superopeator `J_ops`).
    """

    if J_ops is None:
        if c_ops is None:
            raise ValueError("c_ops must be given if J_ops is not")
        J_ops = [sprepost(c, c.dag()) for c in c_ops]

    if rhoss is None:
        if c_ops is None:
            raise ValueError("c_ops must be given if rhoss is not")
        rhoss = steadystate(L, c_ops)

    rhoss_vec = mat2vec(rhoss.full()).ravel()

    N = len(J_ops)
    I = np.zeros(N)

    for i, Ji in enumerate(J_ops):
        I[i] = expect_rho_vec(Ji.data, rhoss_vec, 1)

    return I
コード例 #22
0
ファイル: correlation.py プロジェクト: kwyip/qutip
def _spectrum_pi(H, wlist, c_ops, a_op, b_op, use_pinv=False):
    """
    Internal function for calculating the spectrum of the correlation function
    :math:`\left<A(\\tau)B(0)\\right>`.
    """

    L = H if issuper(H) else liouvillian(H, c_ops)

    tr_mat = tensor([qeye(n) for n in L.dims[0][0]])
    N = np.prod(L.dims[0][0])

    A = L.full()
    b = spre(b_op).full()
    a = spre(a_op).full()

    tr_vec = np.transpose(mat2vec(tr_mat.full()))

    rho_ss = steadystate(L)
    rho = np.transpose(mat2vec(rho_ss.full()))

    I = np.identity(N * N)
    P = np.kron(np.transpose(rho), tr_vec)
    Q = I - P

    spectrum = np.zeros(len(wlist))

    for idx, w in enumerate(wlist):
        if use_pinv:
            MMR = np.linalg.pinv(-1.0j * w * I + A)
        else:
            MMR = np.dot(Q, np.linalg.solve(-1.0j * w * I + A, Q))

        s = np.dot(tr_vec,
                   np.dot(a, np.dot(MMR, np.dot(b, np.transpose(rho)))))
        spectrum[idx] = -2 * np.real(s[0, 0])

    return spectrum
コード例 #23
0
ファイル: test_subsys_apply.py プロジェクト: yipk2/qutip
    def test_SimpleSuperApply(self):
        """
        Non-composite system, operator on Liouville space.
        """
        rho_3 = rand_dm(3)
        superop = kraus_to_super(rand_kraus_map(3))
        analytic_result = vec2mat(superop.data.todense() *
                                  mat2vec(rho_3.data.todense()))

        naive_result = subsystem_apply(rho_3, superop, [True], reference=True)
        naive_diff = (analytic_result - naive_result).data.todense()
        assert_(norm(naive_diff) < 1e-12)

        efficient_result = subsystem_apply(rho_3, superop, [True])
        efficient_diff = (efficient_result - analytic_result).data.todense()
        assert_(norm(efficient_diff) < 1e-12)
コード例 #24
0
def mesolve_const_checkpoint(H, rho0, tlist, c_op_list, e_ops, args, opt,
                             progress_bar, save, subdir):
    """
    Evolve the density matrix using an ODE solver, for constant hamiltonian
    and collapse operators.
    """

    if debug:
        print(inspect.stack()[0][3])

    #
    # check initial state
    #
    if isket(rho0):
        # Got a wave function as initial state: convert to density matrix.
        rho0 = ket2dm(rho0)

    #
    # construct liouvillian
    #
    if opt.tidy:
        H = H.tidyup(opt.atol)

    L = liouvillian(H, c_op_list)

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full()).ravel()
    r = scipy.integrate.ode(cy_ode_rhs)
    r.set_f_params(L.data.data, L.data.indices, L.data.indptr)
    r.set_integrator('zvode',
                     method=opt.method,
                     order=opt.order,
                     atol=opt.atol,
                     rtol=opt.rtol,
                     nsteps=opt.nsteps,
                     first_step=opt.first_step,
                     min_step=opt.min_step,
                     max_step=opt.max_step)
    r.set_initial_value(initial_vector, tlist[0])

    #
    # call generic ODE code
    #
    return generic_ode_solve_checkpoint(r, rho0, tlist, e_ops, opt,
                                        progress_bar, save, subdir)
コード例 #25
0
    def test_SimpleSuperApply(self):
        """
        Non-composite system, operator on Liouville space.
        """
        rho_3 = rand_dm(3)
        superop = kraus_to_super(rand_kraus_map(3))
        analytic_result = vec2mat(superop.data.todense() *
                                  mat2vec(rho_3.data.todense()))

        naive_result = subsystem_apply(rho_3, superop, [True],
                                       reference=True)
        naive_diff = (analytic_result - naive_result).data.todense()
        assert_(norm(naive_diff) < 1e-12)

        efficient_result = subsystem_apply(rho_3, superop, [True])
        efficient_diff = (efficient_result - analytic_result).data.todense()
        assert_(norm(efficient_diff) < 1e-12)
コード例 #26
0
    def propagation_multiple(self):
        '''
          This function will save all the propators during the evolution, which may be memory consuming.
          '''
        if len(self.Hamiltonian_derivative) < 2:
            raise TypeError(
                'this is a multiparameter scenario, the length of dH has to be larger than 1!'
            )

        num = len(self.times)
        dim = self.freeHamiltonian.dims[0][0]
        dt = self.times[1] - self.times[0]
        dL = [
            Qobj(liouvillian(self.Hamiltonian_derivative[i]).full())
            for i in range(0, len(self.Hamiltonian_derivative))
        ]
        D = [[[] for i in range(0, num + 1)] for k in range(0, num + 1)]

        rhovec = [[] for i in range(0, num)]
        drhovec = [[[] for k in range(0, len(self.Hamiltonian_derivative))]
                   for i in range(0, num)]
        rhovec[0] = Qobj(mat2vec(self.rho_initial.full()))

        for para_i in range(0, len(self.Hamiltonian_derivative)):
            drhovec[0][para_i] = dt * dL[para_i] * rhovec[0]

        D[0][0] = self.evolution(0)
        D[1][0] = qeye(dim**2)
        for di in range(1, num):
            tnow = self.times[0] + dt * di
            D[di + 1][di] = qeye(dim**2)
            D[di][di] = self.evolution(tnow)
            D[0][di] = D[di][di] * D[0][di - 1]
            rhovec[di] = D[di][di] * rhovec[di - 1]

            for para_i in range(0, len(self.Hamiltonian_derivative)):
                drho_temp = dt * dL[para_i] * rhovec[di]
                for dj in range(1, di):
                    D[di - dj][di] = D[di - dj + 1][di] * D[di - dj][di - dj]
                    drho_temp += dt * D[di - dj +
                                        1][di] * dL[para_i] * rhovec[di - dj]
                drhovec[di][para_i] = drho_temp

        self.rho = rhovec
        self.rho_derivative = drhovec
        self.propagator = D
コード例 #27
0
    def test_SimpleSuperApply(self):
        """
        Non-composite system, operator on Liouville space.
        """
        tol = 1e-12
        rho_3 = rand_dm(3)
        superop = kraus_to_super(rand_kraus_map(3))
        analytic_result = vec2mat(superop.full() @ mat2vec(rho_3.full()))
        naive_result = subsystem_apply(rho_3, superop, [True], reference=True)
        naive_diff = (analytic_result - naive_result).full()
        naive_diff_norm = norm(naive_diff)
        assert_(naive_diff_norm < tol,
                msg="SimpleSuper: naive_diff_norm {} "
                "is beyond tolerance {}".format(naive_diff_norm, tol))

        efficient_result = subsystem_apply(rho_3, superop, [True])
        efficient_diff = (efficient_result - analytic_result).full()
        efficient_diff_norm = norm(efficient_diff)
        assert_(efficient_diff_norm < tol,
                msg="SimpleSuper: efficient_diff_norm {} "
                "is beyond tolerance {}".format(efficient_diff_norm, tol))
コード例 #28
0
ファイル: test_subsys_apply.py プロジェクト: kafischer/qutip
    def test_SimpleSuperApply(self):
        """
        Non-composite system, operator on Liouville space.
        """
        tol = 1e-12
        rho_3 = rand_dm(3)
        superop = kraus_to_super(rand_kraus_map(3))
        analytic_result = vec2mat(superop.data.todense() * mat2vec(rho_3.data.todense()))

        naive_result = subsystem_apply(rho_3, superop, [True], reference=True)
        naive_diff = (analytic_result - naive_result).data.todense()
        naive_diff_norm = norm(naive_diff)
        assert_(
            naive_diff_norm < tol,
            msg="SimpleSuper: naive_diff_norm {} " "is beyond tolerance {}".format(naive_diff_norm, tol),
        )

        efficient_result = subsystem_apply(rho_3, superop, [True])
        efficient_diff = (efficient_result - analytic_result).data.todense()
        efficient_diff_norm = norm(efficient_diff)
        assert_(
            efficient_diff_norm < tol,
            msg="SimpleSuper: efficient_diff_norm {} " "is beyond tolerance {}".format(efficient_diff_norm, tol),
        )
コード例 #29
0
ファイル: mesolve.py プロジェクト: Vutshi/qutip
def _mesolve_list_func_td(H_list, rho0, tlist, c_list, e_ops, args, opt,
                          progress_bar):
    """
    Internal function for solving the master equation. See mesolve for usage.
    """

    if debug:
        print(inspect.stack()[0][3])

    #
    # check initial state
    #
    if isket(rho0):
        rho0 = rho0 * rho0.dag()

    #
    # construct liouvillian in list-function format
    #
    L_list = []
    if opt.rhs_with_state:
        constant_func = lambda x, y, z: 1.0
    else:
        constant_func = lambda x, y: 1.0

    # add all hamitonian terms to the lagrangian list
    for h_spec in H_list:

        if isinstance(h_spec, Qobj):
            h = h_spec
            h_coeff = constant_func

        elif isinstance(h_spec, list) and isinstance(h_spec[0], Qobj):
            h = h_spec[0]
            h_coeff = h_spec[1]

        else:
            raise TypeError("Incorrect specification of time-dependent " +
                            "Hamiltonian (expected callback function)")

        if isoper(h):
            L_list.append([(-1j * (spre(h) - spost(h))).data, h_coeff, False])

        elif issuper(h):
            L_list.append([h.data, h_coeff, False])

        else:
            raise TypeError("Incorrect specification of time-dependent " +
                            "Hamiltonian (expected operator or superoperator)")

    # add all collapse operators to the lagrangian list
    for c_spec in c_list:

        if isinstance(c_spec, Qobj):
            c = c_spec
            c_coeff = constant_func
            c_square = False

        elif isinstance(c_spec, list) and isinstance(c_spec[0], Qobj):
            c = c_spec[0]
            c_coeff = c_spec[1]
            c_square = True

        else:
            raise TypeError("Incorrect specification of time-dependent " +
                            "collapse operators (expected callback function)")

        if isoper(c):
            cdc = c.dag() * c
            L_list.append([
                liouvillian_fast(None, [c], data_only=True), c_coeff, c_square
            ])

        elif issuper(c):
            L_list.append([c.data, c_coeff, c_square])

        else:
            raise TypeError("Incorrect specification of time-dependent " +
                            "collapse operators (expected operator or " +
                            "superoperator)")

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full()).ravel()
    if opt.rhs_with_state:
        r = scipy.integrate.ode(drho_list_td_with_state)
    else:
        r = scipy.integrate.ode(drho_list_td)
    r.set_integrator('zvode',
                     method=opt.method,
                     order=opt.order,
                     atol=opt.atol,
                     rtol=opt.rtol,
                     nsteps=opt.nsteps,
                     first_step=opt.first_step,
                     min_step=opt.min_step,
                     max_step=opt.max_step)
    r.set_initial_value(initial_vector, tlist[0])
    r.set_f_params(L_list, args)

    #
    # call generic ODE code
    #
    return _generic_ode_solve(r, rho0, tlist, e_ops, opt, progress_bar)
コード例 #30
0
ファイル: propagator.py プロジェクト: mil52603/qutip
def propagator(H, t, c_op_list=[], args={}, options=None,
               parallel=False, progress_bar=None, **kwargs):
    """
    Calculate the propagator U(t) for the density matrix or wave function such
    that :math:`\psi(t) = U(t)\psi(0)` or
    :math:`\\rho_{\mathrm vec}(t) = U(t) \\rho_{\mathrm vec}(0)`
    where :math:`\\rho_{\mathrm vec}` is the vector representation of the
    density matrix.

    Parameters
    ----------
    H : qobj or list
        Hamiltonian as a Qobj instance of a nested list of Qobjs and
        coefficients in the list-string or list-function format for
        time-dependent Hamiltonians (see description in :func:`qutip.mesolve`).

    t : float or array-like
        Time or list of times for which to evaluate the propagator.

    c_op_list : list
        List of qobj collapse operators.

    args : list/array/dictionary
        Parameters to callback functions for time-dependent Hamiltonians and
        collapse operators.

    options : :class:`qutip.Options`
        with options for the ODE solver.

    parallel : bool {False, True}
        Run the propagator in parallel mode.
    
    progress_bar: BaseProgressBar
        Optional instance of BaseProgressBar, or a subclass thereof, for
        showing the progress of the simulation. By default no progress bar
        is used, and if set to True a TextProgressBar will be used.

    Returns
    -------
     a : qobj
        Instance representing the propagator :math:`U(t)`.

    """
    
    kw = _default_kwargs()
    if 'num_cpus' in kwargs:
        num_cpus = kwargs['num_cpus']
    else:
        num_cpus = kw['num_cpus']
    
    if progress_bar is None:
        progress_bar = BaseProgressBar()
    elif progress_bar is True:
        progress_bar = TextProgressBar()

    if options is None:
        options = Options()
        options.rhs_reuse = True
        rhs_clear()

    if isinstance(t, (int, float, np.integer, np.floating)):
        tlist = [0, t]
    else:
        tlist = t

    td_type = _td_format_check(H, c_op_list, solver='me')[2]
    if td_type > 0:
        rhs_generate(H, c_op_list, args=args, options=options)
        
    if isinstance(H, (types.FunctionType, types.BuiltinFunctionType,
                      functools.partial)):
        H0 = H(0.0, args)
    elif isinstance(H, list):
        H0 = H[0][0] if isinstance(H[0], list) else H[0]
    else:
        H0 = H

    if len(c_op_list) == 0 and H0.isoper:
        # calculate propagator for the wave function

        N = H0.shape[0]
        dims = H0.dims
        u = np.zeros([N, N, len(tlist)], dtype=complex)
        
        if parallel:
            output = parallel_map(_parallel_sesolve,range(N),
                    task_args=(N,H,tlist,args,options),
                    progress_bar=progress_bar, num_cpus=num_cpus)
            for n in range(N):
                for k, t in enumerate(tlist):
                    u[:, n, k] = output[n].states[k].full().T 
        else:
            progress_bar.start(N)
            for n in range(0, N):
                progress_bar.update(n)
                psi0 = basis(N, n)
                output = sesolve(H, psi0, tlist, [], args, options)
                for k, t in enumerate(tlist):
                    u[:, n, k] = output.states[k].full().T
            progress_bar.finished()

        # todo: evolving a batch of wave functions:
        # psi_0_list = [basis(N, n) for n in range(N)]
        # psi_t_list = mesolve(H, psi_0_list, [0, t], [], [], args, options)
        # for n in range(0, N):
        #    u[:,n] = psi_t_list[n][1].full().T

    elif len(c_op_list) == 0 and H0.issuper:
        # calculate the propagator for the vector representation of the
        # density matrix (a superoperator propagator)

        N = H0.shape[0]
        sqrt_N = int(np.sqrt(N))
        dims = H0.dims
        
        u = np.zeros([N, N, len(tlist)], dtype=complex)

        if parallel:
            output = parallel_map(_parallel_mesolve,range(N * N),
                    task_args=(sqrt_N,H,tlist,c_op_list,args,options),
                    progress_bar=progress_bar, num_cpus=num_cpus)
            for n in range(N * N):
                for k, t in enumerate(tlist):
                    u[:, n, k] = mat2vec(output[n].states[k].full()).T
        else:
            progress_bar.start(N)
            for n in range(0, N):
                progress_bar.update(n)
                col_idx, row_idx = np.unravel_index(n,(sqrt_N,sqrt_N))
                rho0 = Qobj(sp.csr_matrix(([1],([row_idx],[col_idx])), shape=(sqrt_N,sqrt_N), dtype=complex))
                output = mesolve(H, rho0, tlist, [], [], args, options)
                for k, t in enumerate(tlist):
                    u[:, n, k] = mat2vec(output.states[k].full()).T
            progress_bar.finished()

    else:
        # calculate the propagator for the vector representation of the
        # density matrix (a superoperator propagator)

        N = H0.shape[0]
        dims = [H0.dims, H0.dims]

        u = np.zeros([N * N, N * N, len(tlist)], dtype=complex)
        
        if parallel:
            output = parallel_map(_parallel_mesolve,range(N * N),
                    task_args=(N,H,tlist,c_op_list,args,options),
                    progress_bar=progress_bar, num_cpus=num_cpus)
            for n in range(N * N):
                for k, t in enumerate(tlist):
                    u[:, n, k] = mat2vec(output[n].states[k].full()).T
        else:
            progress_bar.start(N * N)
            for n in range(N * N):
                progress_bar.update(n)
                col_idx, row_idx = np.unravel_index(n,(N,N))
                rho0 = Qobj(sp.csr_matrix(([1],([row_idx],[col_idx])), shape=(N,N), dtype=complex))
                output = mesolve(H, rho0, tlist, c_op_list, [], args, options)
                for k, t in enumerate(tlist):
                    u[:, n, k] = mat2vec(output.states[k].full()).T
            progress_bar.finished()

    if len(tlist) == 2:
        return Qobj(u[:, :, 1], dims=dims)
    else:
        return np.array([Qobj(u[:, :, k], dims=dims) for k in range(len(tlist))], dtype=object)
コード例 #31
0
ファイル: floquet.py プロジェクト: Marata459/qutip
def floquet_markov_mesolve(R, ekets, rho0, tlist, e_ops, f_modes_table=None,
                           options=None, floquet_basis=True):
    """
    Solve the dynamics for the system using the Floquet-Markov master equation.
    """

    if options is None:
        opt = Options()
    else:
        opt = options

    if opt.tidy:
        R.tidyup()

    #
    # check initial state
    #
    if isket(rho0):
        # Got a wave function as initial state: convert to density matrix.
        rho0 = ket2dm(rho0)

    #
    # prepare output array
    #
    n_tsteps = len(tlist)
    dt = tlist[1] - tlist[0]

    output = Result()
    output.solver = "fmmesolve"
    output.times = tlist

    if isinstance(e_ops, FunctionType):
        n_expt_op = 0
        expt_callback = True

    elif isinstance(e_ops, list):

        n_expt_op = len(e_ops)
        expt_callback = False

        if n_expt_op == 0:
            output.states = []
        else:
            if not f_modes_table:
                raise TypeError("The Floquet mode table has to be provided " +
                                "when requesting expectation values.")

            output.expect = []
            output.num_expect = n_expt_op
            for op in e_ops:
                if op.isherm:
                    output.expect.append(np.zeros(n_tsteps))
                else:
                    output.expect.append(np.zeros(n_tsteps, dtype=complex))

    else:
        raise TypeError("Expectation parameter must be a list or a function")

    #
    # transform the initial density matrix to the eigenbasis: from
    # computational basis to the floquet basis
    #
    if ekets is not None:
        rho0 = rho0.transform(ekets)

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full())
    r = scipy.integrate.ode(cy_ode_rhs)
    r.set_f_params(R.data.data, R.data.indices, R.data.indptr)
    r.set_integrator('zvode', method=opt.method, order=opt.order,
                     atol=opt.atol, rtol=opt.rtol, max_step=opt.max_step)
    r.set_initial_value(initial_vector, tlist[0])

    #
    # start evolution
    #
    rho = Qobj(rho0)

    t_idx = 0
    for t in tlist:
        if not r.successful():
            break

        rho.data = vec2mat(r.y)

        if expt_callback:
            # use callback method
            if floquet_basis:
                e_ops(t, Qobj(rho))
            else:
                f_modes_table_t, T = f_modes_table
                f_modes_t = floquet_modes_t_lookup(f_modes_table_t, t, T)
                e_ops(t, Qobj(rho).transform(f_modes_t, True))
        else:
            # calculate all the expectation values, or output rho if
            # no operators
            if n_expt_op == 0:
                if floquet_basis:
                    output.states.append(Qobj(rho))
                else:
                    f_modes_table_t, T = f_modes_table
                    f_modes_t = floquet_modes_t_lookup(f_modes_table_t, t, T)
                    output.states.append(Qobj(rho).transform(f_modes_t, True))
            else:
                f_modes_table_t, T = f_modes_table
                f_modes_t = floquet_modes_t_lookup(f_modes_table_t, t, T)
                for m in range(0, n_expt_op):
                    output.expect[m][t_idx] = \
                        expect(e_ops[m], rho.transform(f_modes_t, False))

        r.integrate(r.t + dt)
        t_idx += 1

    return output
コード例 #32
0
ファイル: mesolve.py プロジェクト: wa4557/qutip
def _mesolve_func_td(L_func, rho0, tlist, c_op_list, e_ops, args, opt, progress_bar):
    """
    Evolve the density matrix using an ODE solver with time dependent
    Hamiltonian.
    """

    if debug:
        print(inspect.stack()[0][3])

    #
    # check initial state
    #
    if isket(rho0):
        rho0 = ket2dm(rho0)

    #
    # construct liouvillian
    #
    new_args = None

    if len(c_op_list) > 0:
        L_data = liouvillian(None, c_op_list).data
    else:
        n, m = rho0.shape
        L_data = sp.csr_matrix((n ** 2, m ** 2), dtype=complex)

    if type(args) is dict:
        new_args = {}
        for key in args:
            if isinstance(args[key], Qobj):
                if isoper(args[key]):
                    new_args[key] = (-1j * (spre(args[key]) - spost(args[key]))).data
                else:
                    new_args[key] = args[key].data
            else:
                new_args[key] = args[key]

    elif type(args) is list or type(args) is tuple:
        new_args = []
        for arg in args:
            if isinstance(arg, Qobj):
                if isoper(arg):
                    new_args.append((-1j * (spre(arg) - spost(arg))).data)
                else:
                    new_args.append(arg.data)
            else:
                new_args.append(arg)

        if type(args) is tuple:
            new_args = tuple(new_args)
    else:
        if isinstance(args, Qobj):
            if isoper(args):
                new_args = (-1j * (spre(args) - spost(args))).data
            else:
                new_args = args.data
        else:
            new_args = args

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full()).ravel()
    if not opt.rhs_with_state:
        r = scipy.integrate.ode(cy_ode_rho_func_td)
    else:
        r = scipy.integrate.ode(_ode_rho_func_td_with_state)
    r.set_integrator(
        "zvode",
        method=opt.method,
        order=opt.order,
        atol=opt.atol,
        rtol=opt.rtol,
        nsteps=opt.nsteps,
        first_step=opt.first_step,
        min_step=opt.min_step,
        max_step=opt.max_step,
    )
    r.set_initial_value(initial_vector, tlist[0])
    r.set_f_params(L_data, L_func, new_args)

    #
    # call generic ODE code
    #
    return _generic_ode_solve(r, rho0, tlist, e_ops, opt, progress_bar)
コード例 #33
0
ファイル: mesolve.py プロジェクト: wa4557/qutip
def _mesolve_list_func_td(H_list, rho0, tlist, c_list, e_ops, args, opt, progress_bar):
    """
    Internal function for solving the master equation. See mesolve for usage.
    """

    if debug:
        print(inspect.stack()[0][3])

    #
    # check initial state
    #
    if isket(rho0):
        rho0 = rho0 * rho0.dag()

    #
    # construct liouvillian in list-function format
    #
    L_list = []
    if opt.rhs_with_state:
        constant_func = lambda x, y, z: 1.0
    else:
        constant_func = lambda x, y: 1.0

    # add all hamitonian terms to the lagrangian list
    for h_spec in H_list:

        if isinstance(h_spec, Qobj):
            h = h_spec
            h_coeff = constant_func

        elif isinstance(h_spec, list) and isinstance(h_spec[0], Qobj):
            h = h_spec[0]
            h_coeff = h_spec[1]

        else:
            raise TypeError("Incorrect specification of time-dependent " + "Hamiltonian (expected callback function)")

        if isoper(h):
            L_list.append([(-1j * (spre(h) - spost(h))).data, h_coeff, False])

        elif issuper(h):
            L_list.append([h.data, h_coeff, False])

        else:
            raise TypeError(
                "Incorrect specification of time-dependent " + "Hamiltonian (expected operator or superoperator)"
            )

    # add all collapse operators to the liouvillian list
    for c_spec in c_list:

        if isinstance(c_spec, Qobj):
            c = c_spec
            c_coeff = constant_func
            c_square = False

        elif isinstance(c_spec, list) and isinstance(c_spec[0], Qobj):
            c = c_spec[0]
            c_coeff = c_spec[1]
            c_square = True

        else:
            raise TypeError(
                "Incorrect specification of time-dependent " + "collapse operators (expected callback function)"
            )

        if isoper(c):
            L_list.append([liouvillian(None, [c], data_only=True), c_coeff, c_square])

        elif issuper(c):
            L_list.append([c.data, c_coeff, c_square])

        else:
            raise TypeError(
                "Incorrect specification of time-dependent "
                + "collapse operators (expected operator or "
                + "superoperator)"
            )

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full()).ravel()
    if opt.rhs_with_state:
        r = scipy.integrate.ode(drho_list_td_with_state)
    else:
        r = scipy.integrate.ode(drho_list_td)
    r.set_integrator(
        "zvode",
        method=opt.method,
        order=opt.order,
        atol=opt.atol,
        rtol=opt.rtol,
        nsteps=opt.nsteps,
        first_step=opt.first_step,
        min_step=opt.min_step,
        max_step=opt.max_step,
    )
    r.set_initial_value(initial_vector, tlist[0])
    r.set_f_params(L_list, args)

    #
    # call generic ODE code
    #
    return _generic_ode_solve(r, rho0, tlist, e_ops, opt, progress_bar)
コード例 #34
0
ファイル: mesolve.py プロジェクト: Vutshi/qutip
def _mesolve_func_td(L_func, rho0, tlist, c_op_list, e_ops, args, opt,
                     progress_bar):
    """!
    Evolve the density matrix using an ODE solver with time dependent
    Hamiltonian.
    """

    if debug:
        print(inspect.stack()[0][3])

    #
    # check initial state
    #
    if isket(rho0):
        rho0 = ket2dm(rho0)

    #
    # construct liouvillian
    #
    new_args = None

    if len(c_op_list) > 0:
        L_data = liouvillian_fast(None, c_op_list).data
    else:
        n, m = rho0.shape
        L_data = sp.csr_matrix((n**2, m**2), dtype=complex)

    if type(args) is dict:
        new_args = {}
        for key in args:
            if isinstance(args[key], Qobj):
                if isoper(args[key]):
                    new_args[key] = (-1j *
                                     (spre(args[key]) - spost(args[key]))).data
                else:
                    new_args[key] = args[key].data
            else:
                new_args[key] = args[key]

    elif type(args) is list:
        new_args = []
        for arg in args:
            if isinstance(arg, Qobj):
                if isoper(arg):
                    new_args.append((-1j * (spre(arg) - spost(arg))).data)
                else:
                    new_args.append(arg.data)
            else:
                new_args.append(arg)

    else:
        if isinstance(args, Qobj):
            if isoper(args):
                new_args = (-1j * (spre(args) - spost(args))).data
            else:
                new_args = args.data
        else:
            new_args = args

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full()).ravel()
    if not opt.rhs_with_state:
        r = scipy.integrate.ode(cy_ode_rho_func_td)
    else:
        r = scipy.integrate.ode(_ode_rho_func_td_with_state)
    r.set_integrator('zvode',
                     method=opt.method,
                     order=opt.order,
                     atol=opt.atol,
                     rtol=opt.rtol,
                     nsteps=opt.nsteps,
                     first_step=opt.first_step,
                     min_step=opt.min_step,
                     max_step=opt.max_step)
    r.set_initial_value(initial_vector, tlist[0])
    r.set_f_params(L_data, L_func, new_args)

    #
    # call generic ODE code
    #
    return _generic_ode_solve(r, rho0, tlist, e_ops, opt, progress_bar)
コード例 #35
0
ファイル: essolve.py プロジェクト: yanghf263/qutip
def ode2es(L, rho0):
    """Creates an exponential series that describes the time evolution for the
    initial density matrix (or state vector) `rho0`, given the Liouvillian
    (or Hamiltonian) `L`.

    .. deprecated:: 4.6.0
        :obj:`~ode2es` will be removed in QuTiP 5.  Please use
        :obj:`Qobj.eigenstates` to get the eigenstates and -values, and use
        :obj:`~QobjEvo` for general time-dependence.

    Parameters
    ----------
    L : qobj
        Liouvillian of the system.

    rho0 : qobj
        Initial state vector or density matrix.

    Returns
    -------
    eseries : :class:`qutip.eseries`
        ``eseries`` represention of the system dynamics.

    """
    if issuper(L):
        # check initial state
        if isket(rho0):
            # Got a wave function as initial state: convert to density matrix.
            rho0 = rho0 * rho0.dag()
        # check if state is below error threshold
        if abs(rho0.full()).sum() < 1e-10 + 1e-24:
            # enforce zero operator
            return eseries(qzero(rho0.dims[0]))
        w, v = L.eigenstates()
        v = np.hstack([ket.full() for ket in v])
        # w[i]   = eigenvalue i
        # v[:,i] = eigenvector i

        rlen = np.prod(rho0.shape)
        r0 = mat2vec(rho0.full())
        v0 = la.solve(v, r0)
        vv = v * sp.spdiags(v0.T, 0, rlen, rlen)

        out = None
        for i in range(rlen):
            qo = Qobj(vec2mat(vv[:, i]), dims=rho0.dims, shape=rho0.shape)
            if out:
                out += eseries(qo, w[i])
            else:
                out = eseries(qo, w[i])

    elif isoper(L):

        if not isket(rho0):
            raise TypeError('Second argument must be a ket if first' +
                            'is a Hamiltonian.')

        # check if state is below error threshold
        if abs(rho0.full()).sum() < 1e-5 + 1e-20:
            # enforce zero operator
            dims = rho0.dims
            return eseries(
                Qobj(sp.csr_matrix((dims[0][0], dims[1][0]), dtype=complex)))

        w, v = L.eigenstates()
        v = np.hstack([ket.full() for ket in v])
        # w[i]   = eigenvalue i
        # v[:,i] = eigenvector i

        rlen = np.prod(rho0.shape)
        r0 = rho0.full()
        v0 = la.solve(v, r0)
        vv = v * sp.spdiags(v0.T, 0, rlen, rlen)

        out = None
        for i in range(rlen):
            qo = Qobj(np.array(vv[:, i]).T, dims=rho0.dims, shape=rho0.shape)
            if out:
                out += eseries(qo, -1.0j * w[i])
            else:
                out = eseries(qo, -1.0j * w[i])

    else:
        raise TypeError('First argument must be a Hamiltonian or Liouvillian.')

    return estidy(out)
コード例 #36
0
def propagator(H,
               t,
               c_op_list=[],
               args={},
               options=None,
               unitary_mode='batch',
               parallel=False,
               progress_bar=None,
               _safe_mode=True,
               **kwargs):
    r"""
    Calculate the propagator U(t) for the density matrix or wave function such
    that :math:`\psi(t) = U(t)\psi(0)` or
    :math:`\rho_{\mathrm vec}(t) = U(t) \rho_{\mathrm vec}(0)`
    where :math:`\rho_{\mathrm vec}` is the vector representation of the
    density matrix.

    Parameters
    ----------
    H : qobj or list
        Hamiltonian as a Qobj instance of a nested list of Qobjs and
        coefficients in the list-string or list-function format for
        time-dependent Hamiltonians (see description in :func:`qutip.mesolve`).

    t : float or array-like
        Time or list of times for which to evaluate the propagator.

    c_op_list : list
        List of qobj collapse operators.

    args : list/array/dictionary
        Parameters to callback functions for time-dependent Hamiltonians and
        collapse operators.

    options : :class:`qutip.Options`
        with options for the ODE solver.

    unitary_mode = str ('batch', 'single')
        Solve all basis vectors simulaneously ('batch') or individually
        ('single').

    parallel : bool {False, True}
        Run the propagator in parallel mode. This will override the
        unitary_mode settings if set to True.

    progress_bar: BaseProgressBar
        Optional instance of BaseProgressBar, or a subclass thereof, for
        showing the progress of the simulation. By default no progress bar
        is used, and if set to True a TextProgressBar will be used.

    Returns
    -------
     a : qobj
        Instance representing the propagator :math:`U(t)`.

    """
    kw = _default_kwargs()
    if 'num_cpus' in kwargs:
        num_cpus = kwargs['num_cpus']
    else:
        num_cpus = kw['num_cpus']

    if progress_bar is None:
        progress_bar = BaseProgressBar()
    elif progress_bar is True:
        progress_bar = TextProgressBar()

    if options is None:
        options = Options()
        options.rhs_reuse = True
        rhs_clear()

    if isinstance(t, (int, float, np.integer, np.floating)):
        tlist = [0, t]
    else:
        tlist = t

    if _safe_mode:
        _solver_safety_check(H, None, c_ops=c_op_list, e_ops=[], args=args)

    td_type = _td_format_check(H, c_op_list, solver='me')

    if isinstance(
            H,
        (types.FunctionType, types.BuiltinFunctionType, functools.partial)):
        H0 = H(0.0, args)
        if unitary_mode == 'batch':
            # batch don't work with function Hamiltonian
            unitary_mode = 'single'
    elif isinstance(H, list):
        H0 = H[0][0] if isinstance(H[0], list) else H[0]
    else:
        H0 = H

    if len(c_op_list) == 0 and H0.isoper:
        # calculate propagator for the wave function

        N = H0.shape[0]
        dims = H0.dims

        if parallel:
            unitary_mode = 'single'
            u = np.zeros([N, N, len(tlist)], dtype=complex)
            output = parallel_map(_parallel_sesolve,
                                  range(N),
                                  task_args=(N, H, tlist, args, options),
                                  progress_bar=progress_bar,
                                  num_cpus=num_cpus)
            for n in range(N):
                for k, t in enumerate(tlist):
                    u[:, n, k] = output[n].states[k].full().T
        else:
            if unitary_mode == 'single':
                output = sesolve(H,
                                 qeye(dims[0]),
                                 tlist, [],
                                 args,
                                 options,
                                 _safe_mode=False)
                if len(tlist) == 2:
                    return output.states[-1]
                else:
                    return output.states

            elif unitary_mode == 'batch':
                u = np.zeros(len(tlist), dtype=object)
                _rows = np.array([(N + 1) * m for m in range(N)])
                _cols = np.zeros_like(_rows)
                _data = np.ones_like(_rows, dtype=complex)
                psi0 = Qobj(sp.coo_matrix((_data, (_rows, _cols))).tocsr())
                if td_type[1] > 0 or td_type[2] > 0:
                    H2 = []
                    for k in range(len(H)):
                        if isinstance(H[k], list):
                            H2.append([tensor(qeye(N), H[k][0]), H[k][1]])
                        else:
                            H2.append(tensor(qeye(N), H[k]))
                else:
                    H2 = tensor(qeye(N), H)
                options.normalize_output = False
                output = sesolve(H2,
                                 psi0,
                                 tlist, [],
                                 args=args,
                                 options=options,
                                 _safe_mode=False)
                for k, t in enumerate(tlist):
                    u[k] = sp_reshape(output.states[k].data, (N, N))
                    unit_row_norm(u[k].data, u[k].indptr, u[k].shape[0])
                    u[k] = u[k].T.tocsr()

            else:
                raise Exception('Invalid unitary mode.')

    elif len(c_op_list) == 0 and H0.issuper:
        # calculate the propagator for the vector representation of the
        # density matrix (a superoperator propagator)
        unitary_mode = 'single'
        N = H0.shape[0]
        sqrt_N = int(np.sqrt(N))
        dims = H0.dims

        u = np.zeros([N, N, len(tlist)], dtype=complex)

        if parallel:
            output = parallel_map(_parallel_mesolve,
                                  range(N * N),
                                  task_args=(sqrt_N, H, tlist, c_op_list, args,
                                             options),
                                  progress_bar=progress_bar,
                                  num_cpus=num_cpus)
            for n in range(N * N):
                for k, t in enumerate(tlist):
                    u[:, n, k] = mat2vec(output[n].states[k].full()).T
        else:
            rho0 = qeye(N, N)
            rho0.dims = [[sqrt_N, sqrt_N], [sqrt_N, sqrt_N]]
            output = mesolve(H,
                             psi0,
                             tlist, [],
                             args,
                             options,
                             _safe_mode=False)
            if len(tlist) == 2:
                return output.states[-1]
            else:
                return output.states

    else:
        # calculate the propagator for the vector representation of the
        # density matrix (a superoperator propagator)
        unitary_mode = 'single'
        N = H0.shape[0]
        dims = [H0.dims, H0.dims]

        u = np.zeros([N * N, N * N, len(tlist)], dtype=complex)

        if parallel:
            output = parallel_map(_parallel_mesolve,
                                  range(N * N),
                                  task_args=(N, H, tlist, c_op_list, args,
                                             options),
                                  progress_bar=progress_bar,
                                  num_cpus=num_cpus)
            for n in range(N * N):
                for k, t in enumerate(tlist):
                    u[:, n, k] = mat2vec(output[n].states[k].full()).T
        else:
            progress_bar.start(N * N)
            for n in range(N * N):
                progress_bar.update(n)
                col_idx, row_idx = np.unravel_index(n, (N, N))
                rho0 = Qobj(
                    sp.csr_matrix(([1], ([row_idx], [col_idx])),
                                  shape=(N, N),
                                  dtype=complex))
                output = mesolve(H,
                                 rho0,
                                 tlist,
                                 c_op_list, [],
                                 args,
                                 options,
                                 _safe_mode=False)
                for k, t in enumerate(tlist):
                    u[:, n, k] = mat2vec(output.states[k].full()).T
            progress_bar.finished()

    if len(tlist) == 2:
        if unitary_mode == 'batch':
            return Qobj(u[-1], dims=dims)
        else:
            return Qobj(u[:, :, 1], dims=dims)
    else:
        if unitary_mode == 'batch':
            return np.array([Qobj(u[k], dims=dims) for k in range(len(tlist))],
                            dtype=object)
        else:
            return np.array(
                [Qobj(u[:, :, k], dims=dims) for k in range(len(tlist))],
                dtype=object)
コード例 #37
0
ファイル: mesolve.py プロジェクト: zaguros/analysis
def _mesolve_func_td(L_func, rho0, tlist, c_op_list, expt_ops, args, opt):
    """!
    Evolve the density matrix using an ODE solver with time dependent
    Hamiltonian.
    """

    if debug:
        print(inspect.stack()[0][3])

    #
    # check initial state
    #
    if isket(rho0):
        rho0 = ket2dm(rho0)

    #
    # construct liouvillian
    #

    if len(c_op_list) > 0:
        L = 0
        for c in c_op_list:
            cdc = c.dag() * c
            L += spre(c) * spost(c.dag()) - 0.5 * spre(cdc) - 0.5 * spost(cdc)

        L_func_and_args = [L_func, L.data]

    else:
        n, m = rho0.shape
        L_func_and_args = [L_func, sp.lil_matrix((n**2, m**2)).tocsr()]

    for arg in args:
        if isinstance(arg, Qobj):
            if isoper(arg):
                L_func_and_args.append((-1j * (spre(arg) - spost(arg))).data)
            else:
                L_func_and_args.append(arg.data)
        else:
            L_func_and_args.append(arg)

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full())
    r = scipy.integrate.ode(_ode_rho_func_td)
    r.set_integrator('zvode',
                     method=opt.method,
                     order=opt.order,
                     atol=opt.atol,
                     rtol=opt.rtol,
                     nsteps=opt.nsteps,
                     first_step=opt.first_step,
                     min_step=opt.min_step,
                     max_step=opt.max_step)
    r.set_initial_value(initial_vector, tlist[0])
    r.set_f_params(L_func_and_args)

    #
    # call generic ODE code
    #
    return _generic_ode_solve(r, rho0, tlist, expt_ops, opt, vec2mat)
コード例 #38
0
ファイル: mesolve.py プロジェクト: ajgpitch/qutip
def _mesolve_list_str_td(H_list, rho0, tlist, c_list, e_ops, args, opt,
                         progress_bar):
    """
    Internal function for solving the master equation. See mesolve for usage.
    """

    if debug:
        print(inspect.stack()[0][3])

    #
    # check initial state: must be a density matrix
    #
    if isket(rho0):
        rho0 = rho0 * rho0.dag()

    #
    # construct liouvillian
    #
    Lconst = 0

    Ldata = []
    Linds = []
    Lptrs = []
    Lcoeff = []
    Lobj = []
    me_cops_coeff = []
    me_cops_obj = []
    me_cops_obj_flags = []

    # loop over all hamiltonian terms, convert to superoperator form and
    # add the data of sparse matrix representation to
    n_not_const_terms = 0
    for h_spec in H_list:
        if isinstance(h_spec, Qobj):
            h = h_spec

            if isoper(h):
                Lconst += -1j * (spre(h) - spost(h))
            elif issuper(h):
                Lconst += h
            else:
                raise TypeError("Incorrect specification of time-dependent " +
                                "Hamiltonian (expected operator or " +
                                "superoperator)")

        elif isinstance(h_spec, list):
            n_not_const_terms +=1
            h = h_spec[0]
            h_coeff = h_spec[1]

            if isoper(h):
                L = -1j * (spre(h) - spost(h))
            elif issuper(h):
                L = h
            else:
                raise TypeError("Incorrect specification of time-dependent " +
                                "Hamiltonian (expected operator or " +
                                "superoperator)")

            Ldata.append(L.data.data)
            Linds.append(L.data.indices)
            Lptrs.append(L.data.indptr)
            if isinstance(h_coeff, Cubic_Spline):
                Lobj.append(h_coeff.coeffs)
            Lcoeff.append(h_coeff)

        else:
            raise TypeError("Incorrect specification of time-dependent " +
                            "Hamiltonian (expected string format)")


    
    # loop over all collapse operators
    for c_spec in c_list:
        if isinstance(c_spec, Qobj):
            c = c_spec

            if isoper(c):
                cdc = c.dag() * c
                Lconst += spre(c) * spost(c.dag()) - 0.5 * spre(cdc) \
                                                   - 0.5 * spost(cdc)
            elif issuper(c):
                Lconst += c
            else:
                raise TypeError("Incorrect specification of time-dependent " +
                                "Liouvillian (expected operator or " +
                                "superoperator)")

        elif isinstance(c_spec, list):
            n_not_const_terms +=1
            c = c_spec[0]
            c_coeff = c_spec[1]
            
            if isoper(c):
                cdc = c.dag() * c
                L = spre(c) * spost(c.dag()) - 0.5 * spre(cdc) \
                                             - 0.5 * spost(cdc)
                if isinstance(c_coeff, Cubic_Spline):
                    me_cops_obj.append(c_coeff.coeffs)
                    me_cops_obj_flags.append(n_not_const_terms)
                    me_cops_coeff.append(c_coeff)
                else:
                    c_coeff = "(" + c_coeff + ")**2"
                    Lcoeff.append(c_coeff)
            elif issuper(c):
                L = c
                if isinstance(c_coeff, Cubic_Spline):
                    me_cops_obj.append(c_coeff.coeffs)
                    me_cops_obj_flags.append(-n_not_const_terms)
                    me_cops_coeff.append(c_coeff)
                else:
                    Lcoeff.append(c_coeff)
            else:
                raise TypeError("Incorrect specification of time-dependent " +
                                "Liouvillian (expected operator or " +
                                "superoperator)")

            Ldata.append(L.data.data)
            Linds.append(L.data.indices)
            Lptrs.append(L.data.indptr)
            #Lcoeff.append(c_coeff)

        else:
            raise TypeError("Incorrect specification of time-dependent " +
                            "collapse operators (expected string format)")
    
    
    #prepend the constant part of the liouvillian
    if Lconst != 0:
       Ldata = [Lconst.data.data]+Ldata
       Linds = [Lconst.data.indices]+Linds
       Lptrs = [Lconst.data.indptr]+Lptrs
       Lcoeff = ["1.0"]+Lcoeff
       
    else:
        me_cops_obj_flags = [kk-1 for kk in me_cops_obj_flags]
    # the total number of liouvillian terms (hamiltonian terms +
    # collapse operators)
    n_L_terms = len(Ldata)
    n_td_cops = len(me_cops_obj)
    
    # Check which components should use OPENMP
    omp_components = None
    if qset.has_openmp:
        if opt.use_openmp:
            omp_components = openmp_components(Lptrs)

    #
    # setup ode args string: we expand the list Ldata, Linds and Lptrs into
    # and explicit list of parameters
    #
    string_list = []
    for k in range(n_L_terms):
        string_list.append("Ldata[%d], Linds[%d], Lptrs[%d]" % (k, k, k))
    
    # Add H object terms to ode args string
    for k in range(len(Lobj)):
        string_list.append("Lobj[%d]" % k)
        
    # Add cop object terms to end of ode args string
    for k in range(len(me_cops_obj)):
        string_list.append("me_cops_obj[%d]" % k)    
    
    for name, value in args.items():
        if isinstance(value, np.ndarray):
            string_list.append(name)
        else:
            string_list.append(str(value))
    parameter_string = ",".join(string_list)
    
    #
    # generate and compile new cython code if necessary
    #
    if not opt.rhs_reuse or config.tdfunc is None:
        if opt.rhs_filename is None:
            config.tdname = "rhs" + str(os.getpid()) + str(config.cgen_num)
        else:
            config.tdname = opt.rhs_filename
        cgen = Codegen(h_terms=len(Lcoeff), h_tdterms=Lcoeff, 
                       c_td_splines=me_cops_coeff, 
                       c_td_spline_flags=me_cops_obj_flags, args=args,
                       config=config, use_openmp=opt.use_openmp,
                       omp_components=omp_components,
                       omp_threads=opt.openmp_threads)
        cgen.generate(config.tdname + ".pyx")

        code = compile('from ' + config.tdname + ' import cy_td_ode_rhs',
                       '<string>', 'exec')
        exec(code, globals())
        config.tdfunc = cy_td_ode_rhs

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full()).ravel('F')
    if issuper(rho0):
        r = scipy.integrate.ode(_td_ode_rhs_super)
        code = compile('r.set_f_params([' + parameter_string + '])',
                       '<string>', 'exec')
    else:
        r = scipy.integrate.ode(config.tdfunc)
        code = compile('r.set_f_params(' + parameter_string + ')',
                       '<string>', 'exec')
    r.set_integrator('zvode', method=opt.method, order=opt.order,
                     atol=opt.atol, rtol=opt.rtol, nsteps=opt.nsteps,
                     first_step=opt.first_step, min_step=opt.min_step,
                     max_step=opt.max_step)
    r.set_initial_value(initial_vector, tlist[0])

    exec(code, locals(), args)

    #
    # call generic ODE code
    #
    return _generic_ode_solve(r, rho0, tlist, e_ops, opt, progress_bar)
コード例 #39
0
ファイル: essolve.py プロジェクト: prvn16/qutip
def ode2es(L, rho0):
    """Creates an exponential series that describes the time evolution for the
    initial density matrix (or state vector) `rho0`, given the Liouvillian
    (or Hamiltonian) `L`.

    Parameters
    ----------
    L : qobj
        Liouvillian of the system.

    rho0 : qobj
        Initial state vector or density matrix.

    Returns
    -------
    eseries : :class:`qutip.eseries`
        ``eseries`` represention of the system dynamics.

    """

    if issuper(L):

        # check initial state
        if isket(rho0):
            # Got a wave function as initial state: convert to density matrix.
            rho0 = rho0 * rho0.dag()

        w, v = L.eigenstates()
        v = np.hstack([ket.full() for ket in v])
        # w[i]   = eigenvalue i
        # v[:,i] = eigenvector i

        rlen = np.prod(rho0.shape)
        r0 = mat2vec(rho0.full())
        v0 = la.solve(v, r0)
        vv = v * sp.spdiags(v0.T, 0, rlen, rlen)

        out = None
        for i in range(rlen):
            qo = Qobj(vec2mat(vv[:, i]), dims=rho0.dims, shape=rho0.shape)
            if out:
                out += eseries(qo, w[i])
            else:
                out = eseries(qo, w[i])

    elif isoper(L):

        if not isket(rho0):
            raise TypeError("Second argument must be a ket if first" + "is a Hamiltonian.")

        w, v = L.eigenstates()
        v = np.hstack([ket.full() for ket in v])
        # w[i]   = eigenvalue i
        # v[:,i] = eigenvector i

        rlen = np.prod(rho0.shape)
        r0 = rho0.full()
        v0 = la.solve(v, r0)
        vv = v * sp.spdiags(v0.T, 0, rlen, rlen)

        out = None
        for i in range(rlen):
            qo = Qobj(np.matrix(vv[:, i]).T, dims=rho0.dims, shape=rho0.shape)
            if out:
                out += eseries(qo, -1.0j * w[i])
            else:
                out = eseries(qo, -1.0j * w[i])

    else:
        raise TypeError("First argument must be a Hamiltonian or Liouvillian.")

    return estidy(out)
コード例 #40
0
ファイル: stochastic.py プロジェクト: silky/qutip
def smesolve_generic(ssdata, options, progress_bar):
    """
    internal

    .. note::

        Experimental.

    """
    if debug:
        print(inspect.stack()[0][3])

    N_store = len(ssdata.tlist)
    N_substeps = ssdata.nsubsteps
    N = N_store * N_substeps
    dt = (ssdata.tlist[1] - ssdata.tlist[0]) / N_substeps
    NT = ssdata.ntraj

    data = Odedata()
    data.solver = "smesolve"
    data.times = ssdata.tlist
    data.expect = np.zeros((len(ssdata.e_ops), N_store), dtype=complex)
    data.ss = np.zeros((len(ssdata.e_ops), N_store), dtype=complex)
    data.noise = []
    data.measurement = []

    # pre-compute suporoperator operator combinations that are commonly needed
    # when evaluating the RHS of stochastic master equations
    A_ops = []
    for c_idx, c in enumerate(ssdata.sc_ops):

        n = c.dag() * c
        A_ops.append([spre(c).data, spost(c).data,
                      spre(c.dag()).data, spost(c.dag()).data,
                      spre(n).data, spost(n).data,
                      (spre(c) * spost(c.dag())).data,
                      lindblad_dissipator(c, data_only=True)])

    s_e_ops = [spre(e) for e in ssdata.e_ops]

    # Liouvillian for the deterministic part.
    # needs to be modified for TD systems
    L = liouvillian_fast(ssdata.H, ssdata.c_ops)

    progress_bar.start(ssdata.ntraj)

    for n in range(ssdata.ntraj):
        progress_bar.update(n)

        rho_t = mat2vec(ssdata.state0.full()).ravel()

        noise = ssdata.noise[n] if ssdata.noise else None

        states_list, dW, m = _smesolve_single_trajectory(
            L, dt, ssdata.tlist, N_store, N_substeps,
            rho_t, A_ops, s_e_ops, data, ssdata.rhs,
            ssdata.d1, ssdata.d2, ssdata.d2_len, ssdata.homogeneous,
            ssdata.distribution, ssdata.args,
            store_measurement=ssdata.store_measurement,
            store_states=ssdata.store_states, noise=noise)

        data.states.append(states_list)
        data.noise.append(dW)
        data.measurement.append(m)

    progress_bar.finished()

    # average density matrices
    if options.average_states and np.any(data.states):
        data.states = [sum(state_list).unit() for state_list in data.states]

    # average
    data.expect = data.expect / NT

    # standard error
    if NT > 1:
        data.se = (data.ss - NT * (data.expect ** 2)) / (NT * (NT - 1))
    else:
        data.se = None

    # convert complex data to real if hermitian
    data.expect = [np.real(data.expect[n,:]) if e.isherm else data.expect[n,:]
                   for n, e in enumerate(ssdata.e_ops)]

    return data
コード例 #41
0
ファイル: mesolve.py プロジェクト: Vutshi/qutip
def _mesolve_list_str_td(H_list, rho0, tlist, c_list, e_ops, args, opt,
                         progress_bar):
    """
    Internal function for solving the master equation. See mesolve for usage.
    """

    if debug:
        print(inspect.stack()[0][3])

    #
    # check initial state: must be a density matrix
    #
    if isket(rho0):
        rho0 = rho0 * rho0.dag()

    #
    # construct liouvillian
    #
    Lconst = 0

    Ldata = []
    Linds = []
    Lptrs = []
    Lcoeff = []

    # loop over all hamiltonian terms, convert to superoperator form and
    # add the data of sparse matrix representation to
    for h_spec in H_list:

        if isinstance(h_spec, Qobj):
            h = h_spec

            if isoper(h):
                Lconst += -1j * (spre(h) - spost(h))
            elif issuper(h):
                Lconst += h
            else:
                raise TypeError("Incorrect specification of time-dependent " +
                                "Hamiltonian (expected operator or " +
                                "superoperator)")

        elif isinstance(h_spec, list):
            h = h_spec[0]
            h_coeff = h_spec[1]

            if isoper(h):
                L = -1j * (spre(h) - spost(h))
            elif issuper(h):
                L = h
            else:
                raise TypeError("Incorrect specification of time-dependent " +
                                "Hamiltonian (expected operator or " +
                                "superoperator)")

            Ldata.append(L.data.data)
            Linds.append(L.data.indices)
            Lptrs.append(L.data.indptr)
            Lcoeff.append(h_coeff)

        else:
            raise TypeError("Incorrect specification of time-dependent " +
                            "Hamiltonian (expected string format)")

    # loop over all collapse operators
    for c_spec in c_list:

        if isinstance(c_spec, Qobj):
            c = c_spec

            if isoper(c):
                cdc = c.dag() * c
                Lconst += spre(c) * spost(c.dag()) - 0.5 * spre(cdc) \
                                                   - 0.5 * spost(cdc)
            elif issuper(c):
                Lconst += c
            else:
                raise TypeError("Incorrect specification of time-dependent " +
                                "Liouvillian (expected operator or " +
                                "superoperator)")

        elif isinstance(c_spec, list):
            c = c_spec[0]
            c_coeff = c_spec[1]

            if isoper(c):
                cdc = c.dag() * c
                L = spre(c) * spost(c.dag()) - 0.5 * spre(cdc) \
                                             - 0.5 * spost(cdc)
                c_coeff = "(" + c_coeff + ")**2"
            elif issuper(c):
                L = c
            else:
                raise TypeError("Incorrect specification of time-dependent " +
                                "Liouvillian (expected operator or " +
                                "superoperator)")

            Ldata.append(L.data.data)
            Linds.append(L.data.indices)
            Lptrs.append(L.data.indptr)
            Lcoeff.append(c_coeff)

        else:
            raise TypeError("Incorrect specification of time-dependent " +
                            "collapse operators (expected string format)")

    # add the constant part of the lagrangian
    if Lconst != 0:
        Ldata.append(Lconst.data.data)
        Linds.append(Lconst.data.indices)
        Lptrs.append(Lconst.data.indptr)
        Lcoeff.append("1.0")

    # the total number of liouvillian terms (hamiltonian terms +
    # collapse operators)
    n_L_terms = len(Ldata)

    #
    # setup ode args string: we expand the list Ldata, Linds and Lptrs into
    # and explicit list of parameters
    #
    string_list = []
    for k in range(n_L_terms):
        string_list.append("Ldata[%d], Linds[%d], Lptrs[%d]" % (k, k, k))
    for name, value in args.items():
        string_list.append(str(value))
    parameter_string = ",".join(string_list)

    #
    # generate and compile new cython code if necessary
    #
    if not opt.rhs_reuse or odeconfig.tdfunc is None:
        if opt.rhs_filename is None:
            odeconfig.tdname = "rhs" + str(odeconfig.cgen_num)
        else:
            odeconfig.tdname = opt.rhs_filename
        cgen = Codegen(h_terms=n_L_terms,
                       h_tdterms=Lcoeff,
                       args=args,
                       odeconfig=odeconfig)
        cgen.generate(odeconfig.tdname + ".pyx")

        code = compile('from ' + odeconfig.tdname + ' import cyq_td_ode_rhs',
                       '<string>', 'exec')
        exec(code, globals())
        odeconfig.tdfunc = cyq_td_ode_rhs

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full()).ravel()
    r = scipy.integrate.ode(odeconfig.tdfunc)
    r.set_integrator('zvode',
                     method=opt.method,
                     order=opt.order,
                     atol=opt.atol,
                     rtol=opt.rtol,
                     nsteps=opt.nsteps,
                     first_step=opt.first_step,
                     min_step=opt.min_step,
                     max_step=opt.max_step)
    r.set_initial_value(initial_vector, tlist[0])
    code = compile('r.set_f_params(' + parameter_string + ')', '<string>',
                   'exec')
    exec(code)

    #
    # call generic ODE code
    #
    return _generic_ode_solve(r, rho0, tlist, e_ops, opt, progress_bar)
コード例 #42
0
ファイル: mesolve.py プロジェクト: Vutshi/qutip
def _mesolve_list_td(H_func, rho0, tlist, c_op_list, e_ops, args, opt,
                     progress_bar):
    """!
    Evolve the density matrix using an ODE solver with time dependent
    Hamiltonian.
    """

    if debug:
        print(inspect.stack()[0][3])

    #
    # check initial state
    #
    if isket(rho0):
        # if initial state is a ket and no collapse operator where given,
        # fall back on the unitary schrodinger equation solver
        if len(c_op_list) == 0:
            return _sesolve_list_td(H_func, rho0, tlist, e_ops, args, opt)

        # Got a wave function as initial state: convert to density matrix.
        rho0 = ket2dm(rho0)

    #
    # construct liouvillian
    #
    if len(H_func) != 2:
        raise TypeError('Time-dependent Hamiltonian list must have two terms.')
    if not isinstance(H_func[0], (list, np.ndarray)) or len(H_func[0]) <= 1:
        raise TypeError('Time-dependent Hamiltonians must be a list ' +
                        'with two or more terms')
    if (not isinstance(H_func[1], (list, np.ndarray))) or \
       (len(H_func[1]) != (len(H_func[0]) - 1)):
        raise TypeError('Time-dependent coefficients must be list with ' +
                        'length N-1 where N is the number of ' +
                        'Hamiltonian terms.')

    if opt.rhs_reuse and odeconfig.tdfunc is None:
        rhs_generate(H_func, args)

    lenh = len(H_func[0])
    if opt.tidy:
        H_func[0] = [(H_func[0][k]).tidyup() for k in range(lenh)]
    L_func = [[liouvillian_fast(H_func[0][0], c_op_list)], H_func[1]]
    for m in range(1, lenh):
        L_func[0].append(liouvillian_fast(H_func[0][m], []))

    # create data arrays for time-dependent RHS function
    Ldata = [L_func[0][k].data.data for k in range(lenh)]
    Linds = [L_func[0][k].data.indices for k in range(lenh)]
    Lptrs = [L_func[0][k].data.indptr for k in range(lenh)]
    # setup ode args string
    string = ""
    for k in range(lenh):
        string += ("Ldata[%d], Linds[%d], Lptrs[%d]," % (k, k, k))

    if args:
        td_consts = args.items()
        for elem in td_consts:
            string += str(elem[1])
            if elem != td_consts[-1]:
                string += (",")

    # run code generator
    if not opt.rhs_reuse or odeconfig.tdfunc is None:
        if opt.rhs_filename is None:
            odeconfig.tdname = "rhs" + str(odeconfig.cgen_num)
        else:
            odeconfig.tdname = opt.rhs_filename
        cgen = Codegen(h_terms=n_L_terms,
                       h_tdterms=Lcoeff,
                       args=args,
                       odeconfig=odeconfig)
        cgen.generate(odeconfig.tdname + ".pyx")

        code = compile('from ' + odeconfig.tdname + ' import cyq_td_ode_rhs',
                       '<string>', 'exec')
        exec(code, globals())
        odeconfig.tdfunc = cyq_td_ode_rhs

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full()).ravel()
    r = scipy.integrate.ode(odeconfig.tdfunc)
    r.set_integrator('zvode',
                     method=opt.method,
                     order=opt.order,
                     atol=opt.atol,
                     rtol=opt.rtol,
                     nsteps=opt.nsteps,
                     first_step=opt.first_step,
                     min_step=opt.min_step,
                     max_step=opt.max_step)
    r.set_initial_value(initial_vector, tlist[0])
    code = compile('r.set_f_params(' + string + ')', '<string>', 'exec')
    exec(code)

    #
    # call generic ODE code
    #
    return _generic_ode_solve(r, rho0, tlist, e_ops, opt, progress_bar)
コード例 #43
0
ファイル: countstat.py プロジェクト: NunoEdgarGub1/qutip
def countstat_current_noise(L, c_ops, wlist=None, rhoss=None, J_ops=None, 
                            sparse=True, method='direct'):
    """
    Compute the cross-current noise spectrum for a list of collapse operators
    `c_ops` corresponding to monitored currents, given the system
    Liouvillian `L`. The current collapse operators `c_ops` should be part
    of the dissipative processes in `L`, but the `c_ops` given here does not
    necessarily need to be all collapse operators contributing to dissipation
    in the Liouvillian. Optionally, the steadystate density matrix `rhoss`
    and the current operators `J_ops` correpsonding to the current collapse 
    operators `c_ops` can also be specified. If either of
    `rhoss` and `J_ops` are omitted, they will be computed internally.
    'wlist' is an optional list of frequencies at which to evaluate the noise 
    spectrum.  
    
    Note:
    The default method is a direct solution using dense matrices, as sparse 
    matrix methods fail for some examples of small systems.
    For larger systems it is reccomended to use the sparse solver
    with the direct method, as it avoids explicit calculation of the
    pseudo-inverse, as described in page 67 of "Electrons in nanostructures"
    C. Flindt, PhD Thesis, available online:
    http://orbit.dtu.dk/fedora/objects/orbit:82314/datastreams/file_4732600/content
    
    Parameters
    ----------

    L : :class:`qutip.Qobj`
        Qobj representing the system Liouvillian.

    c_ops : array / list
        List of current collapse operators.

    rhoss : :class:`qutip.Qobj` (optional)
        The steadystate density matrix corresponding the system Liouvillian
        `L`.
        
    wlist : array / list (optional)
        List of frequencies at which to evaluate (if none are given, evaluates 
        at zero frequency)

    J_ops : array / list (optional)
        List of current superoperators.

    sparse : bool
        Flag that indicates whether to use sparse or dense matrix methods when
        computing the pseudo inverse. Default is false, as sparse solvers
        can fail for small systems. For larger systems the sparse solvers
        are reccomended. 
        
        
    Returns
    --------
    I, S : tuple of arrays
        The currents `I` corresponding to each current collapse operator
        `c_ops` (or, equivalently, each current superopeator `J_ops`) and the
        zero-frequency cross-current correlation `S`.
    """

    if rhoss is None:
        rhoss = steadystate(L, c_ops)

    if J_ops is None:
        J_ops = [sprepost(c, c.dag()) for c in c_ops]

    

    N = len(J_ops)
    I = np.zeros(N)
    
    if wlist is None:
        S = np.zeros((N, N,1))
        wlist=[0.]
    else:
        S = np.zeros((N, N,len(wlist)))
        
    if sparse == False: 
        rhoss_vec = mat2vec(rhoss.full()).ravel()
        for k,w in enumerate(wlist):
            R = pseudo_inverse(L, rhoss=rhoss, w= w, sparse = sparse, method=method)
            for i, Ji in enumerate(J_ops):
                for j, Jj in enumerate(J_ops):
                    if i == j:
                        I[i] = expect_rho_vec(Ji.data, rhoss_vec, 1)
                        S[i, j,k] = I[i]
                    S[i, j,k] -= expect_rho_vec((Ji * R * Jj 
                                                + Jj * R * Ji).data,
                                                rhoss_vec, 1)
    else:
        if method == "direct":
            N = np.prod(L.dims[0][0])
            
            rhoss_vec = operator_to_vector(rhoss)
            
            tr_op = tensor([identity(n) for n in L.dims[0][0]])
            tr_op_vec = operator_to_vector(tr_op)
            
            Pop = sp.kron(rhoss_vec.data, tr_op_vec.data.T, format='csr')
            Iop = sp.eye(N*N, N*N, format='csr')
            Q = Iop - Pop
            
            for k,w in enumerate(wlist):
                
                if w != 0.0:    
                    L_temp = 1.0j*w*spre(tr_op) + L
                else: #At zero frequency some solvers fail for small systems.
                      #Adding a small finite frequency of order 1e-15
                      #helps prevent the solvers from throwing an exception.
                    L_temp =  1.0j*(1e-15)*spre(tr_op) + L
                    
                if not settings.has_mkl:
                    A = L_temp.data.tocsc()
                else:
                    A = L_temp.data.tocsr()
                    A.sort_indices()                      
                      
                rhoss_vec = mat2vec(rhoss.full()).ravel()               
                
                for j, Jj in enumerate(J_ops):
                    Qj = Q.dot( Jj.data.dot( rhoss_vec))
                    try:
                        if settings.has_mkl:
                            X_rho_vec_j = mkl_spsolve(A,Qj)                            
                        else:
                            X_rho_vec_j = sp.linalg.splu(A, permc_spec
                                                 ='COLAMD').solve(Qj)
                    except:
                        X_rho_vec_j = sp.linalg.lsqr(A,Qj)[0]
                    for i, Ji in enumerate(J_ops):
                        Qi = Q.dot( Ji.data.dot(rhoss_vec))
                        try:
                            if settings.has_mkl:                              
                                X_rho_vec_i = mkl_spsolve(A,Qi)  
                            else:
                                X_rho_vec_i = sp.linalg.splu(A, permc_spec
                                                     ='COLAMD').solve(Qi)
                        except:
                             X_rho_vec_i = sp.linalg.lsqr(A,Qi)[0]
                        if i == j:
                            I[i] = expect_rho_vec(Ji.data, 
                                                 rhoss_vec, 1)
                            S[j, i, k] = I[i]
                        
                        S[j, i, k] -= (expect_rho_vec(Jj.data * Q, 
                                        X_rho_vec_i, 1) 
                                        + expect_rho_vec(Ji.data * Q, 
                                        X_rho_vec_j, 1))

        else:
            rhoss_vec = mat2vec(rhoss.full()).ravel()
            for k,w in enumerate(wlist):

                R = pseudo_inverse(L,rhoss=rhoss, w= w, sparse = sparse, 
                                   method=method)
                                   
                for i, Ji in enumerate(J_ops):
                    for j, Jj in enumerate(J_ops):
                        if i == j:
                            I[i] = expect_rho_vec(Ji.data, rhoss_vec, 1)
                            S[i, j, k] = I[i]
                        S[i, j, k] -= expect_rho_vec((Ji * R * Jj 
                                                     + Jj * R * Ji).data,
                                                     rhoss_vec, 1)
    return I, S
コード例 #44
0
ファイル: bloch_redfield.py プロジェクト: JonathanUlm/qutip
def bloch_redfield_solve(R, ekets, rho0, tlist, e_ops=[], options=None):
    """
    Evolve the ODEs defined by Bloch-Redfield master equation. The
    Bloch-Redfield tensor can be calculated by the function
    :func:`bloch_redfield_tensor`.

    Parameters
    ----------

    R : :class:`qutip.qobj`
        Bloch-Redfield tensor.

    ekets : array of :class:`qutip.qobj`
        Array of kets that make up a basis tranformation for the eigenbasis.

    rho0 : :class:`qutip.qobj`
        Initial density matrix.

    tlist : *list* / *array*
        List of times for :math:`t`.

    e_ops : list of :class:`qutip.qobj` / callback function
        List of operators for which to evaluate expectation values.

    options : :class:`qutip.Qdeoptions`
        Options for the ODE solver.

    Returns
    -------

    output: :class:`qutip.solver`

        An instance of the class :class:`qutip.solver`, which contains either
        an *array* of expectation values for the times specified by `tlist`.

    """

    if options is None:
        options = Options()

    if options.tidy:
        R.tidyup()

    #
    # check initial state
    #
    if isket(rho0):
        # Got a wave function as initial state: convert to density matrix.
        rho0 = rho0 * rho0.dag()

    #
    # prepare output array
    #
    n_tsteps = len(tlist)
    dt = tlist[1] - tlist[0]
    result_list = []

    #
    # transform the initial density matrix and the e_ops opterators to the
    # eigenbasis
    #
    rho_eb = rho0.transform(ekets)
    e_eb_ops = [e.transform(ekets) for e in e_ops]

    for e_eb in e_eb_ops:
        result_list.append(np.zeros(n_tsteps, dtype=complex))

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho_eb.full())
    r = scipy.integrate.ode(cy_ode_rhs)
    r.set_f_params(R.data.data, R.data.indices, R.data.indptr)
    r.set_integrator('zvode', method=options.method, order=options.order,
                     atol=options.atol, rtol=options.rtol,
                     nsteps=options.nsteps, first_step=options.first_step,
                     min_step=options.min_step, max_step=options.max_step)
    r.set_initial_value(initial_vector, tlist[0])

    #
    # start evolution
    #
    dt = np.diff(tlist)
    for t_idx, _ in enumerate(tlist):

        if not r.successful():
            break

        rho_eb.data = vec2mat(r.y)

        # calculate all the expectation values, or output rho_eb if no
        # expectation value operators are given
        if e_ops:
            rho_eb_tmp = Qobj(rho_eb)
            for m, e in enumerate(e_eb_ops):
                result_list[m][t_idx] = expect(e, rho_eb_tmp)
        else:
            result_list.append(rho_eb.transform(ekets, True))

        if t_idx < n_tsteps - 1:
            r.integrate(r.t + dt[t_idx])

    return result_list
コード例 #45
0
ファイル: propagator.py プロジェクト: anubhavvardhan/qutip
def propagator(H, t, c_op_list=[], args={}, options=None,
               unitary_mode='batch', parallel=False, 
               progress_bar=None, **kwargs):
    """
    Calculate the propagator U(t) for the density matrix or wave function such
    that :math:`\psi(t) = U(t)\psi(0)` or
    :math:`\\rho_{\mathrm vec}(t) = U(t) \\rho_{\mathrm vec}(0)`
    where :math:`\\rho_{\mathrm vec}` is the vector representation of the
    density matrix.

    Parameters
    ----------
    H : qobj or list
        Hamiltonian as a Qobj instance of a nested list of Qobjs and
        coefficients in the list-string or list-function format for
        time-dependent Hamiltonians (see description in :func:`qutip.mesolve`).

    t : float or array-like
        Time or list of times for which to evaluate the propagator.

    c_op_list : list
        List of qobj collapse operators.

    args : list/array/dictionary
        Parameters to callback functions for time-dependent Hamiltonians and
        collapse operators.

    options : :class:`qutip.Options`
        with options for the ODE solver.

    unitary_mode = str ('batch', 'single')
        Solve all basis vectors simulaneously ('batch') or individually 
        ('single').
    
    parallel : bool {False, True}
        Run the propagator in parallel mode. This will override the 
        unitary_mode settings if set to True.
    
    progress_bar: BaseProgressBar
        Optional instance of BaseProgressBar, or a subclass thereof, for
        showing the progress of the simulation. By default no progress bar
        is used, and if set to True a TextProgressBar will be used.

    Returns
    -------
     a : qobj
        Instance representing the propagator :math:`U(t)`.

    """
    kw = _default_kwargs()
    if 'num_cpus' in kwargs:
        num_cpus = kwargs['num_cpus']
    else:
        num_cpus = kw['num_cpus']
    
    if progress_bar is None:
        progress_bar = BaseProgressBar()
    elif progress_bar is True:
        progress_bar = TextProgressBar()

    if options is None:
        options = Options()
        options.rhs_reuse = True
        rhs_clear()

    if isinstance(t, (int, float, np.integer, np.floating)):
        tlist = [0, t]
    else:
        tlist = t

    td_type = _td_format_check(H, c_op_list, solver='me')
        
    if isinstance(H, (types.FunctionType, types.BuiltinFunctionType,
                      functools.partial)):
        H0 = H(0.0, args)
    elif isinstance(H, list):
        H0 = H[0][0] if isinstance(H[0], list) else H[0]
    else:
        H0 = H
    
    if len(c_op_list) == 0 and H0.isoper:
        # calculate propagator for the wave function

        N = H0.shape[0]
        dims = H0.dims
        
        if parallel:
            unitary_mode = 'single'
            u = np.zeros([N, N, len(tlist)], dtype=complex)
            output = parallel_map(_parallel_sesolve,range(N),
                    task_args=(N,H, tlist,args,options),
                    progress_bar=progress_bar, num_cpus=num_cpus)
            for n in range(N):
                for k, t in enumerate(tlist):
                    u[:, n, k] = output[n].states[k].full().T 
        else:
            if unitary_mode == 'single':
                u = np.zeros([N, N, len(tlist)], dtype=complex)
                progress_bar.start(N)
                for n in range(0, N):
                    progress_bar.update(n)
                    psi0 = basis(N, n)
                    output = sesolve(H, psi0, tlist, [], args, options, _safe_mode=False) 
                    for k, t in enumerate(tlist):
                        u[:, n, k] = output.states[k].full().T
                    progress_bar.finished() 

            elif unitary_mode =='batch':
                u = np.zeros(len(tlist), dtype=object)
                _rows = np.array([(N+1)*m for m in range(N)])
                _cols = np.zeros_like(_rows)
                _data = np.ones_like(_rows,dtype=complex)
                psi0 = Qobj(sp.coo_matrix((_data,(_rows,_cols))).tocsr())
                if td_type[1] > 0 or td_type[2] > 0:
                    H2 = []
                    for k in range(len(H)):
                        if isinstance(H[k], list):
                            H2.append([tensor(qeye(N), H[k][0]), H[k][1]])
                        else:
                            H2.append(tensor(qeye(N), H[k]))
                else:
                    H2 = tensor(qeye(N), H)
                output = sesolve(H2, psi0, tlist, [] , args = args, _safe_mode=False, 
                             options=Options(normalize_output=False))
                for k, t in enumerate(tlist):
                    u[k] = sp_reshape(output.states[k].data, (N, N))
                    unit_row_norm(u[k].data, u[k].indptr, u[k].shape[0])
                    u[k] = u[k].T.tocsr()
            else:
                raise Exception('Invalid unitary mode.')
                        

    elif len(c_op_list) == 0 and H0.issuper:
        # calculate the propagator for the vector representation of the
        # density matrix (a superoperator propagator)
        unitary_mode = 'single'
        N = H0.shape[0]
        sqrt_N = int(np.sqrt(N))
        dims = H0.dims
        
        u = np.zeros([N, N, len(tlist)], dtype=complex)

        if parallel:
            output = parallel_map(_parallel_mesolve,range(N * N),
                    task_args=(sqrt_N,H,tlist,c_op_list,args,options),
                    progress_bar=progress_bar, num_cpus=num_cpus)
            for n in range(N * N):
                for k, t in enumerate(tlist):
                    u[:, n, k] = mat2vec(output[n].states[k].full()).T
        else:
            progress_bar.start(N)
            for n in range(0, N):
                progress_bar.update(n)
                col_idx, row_idx = np.unravel_index(n,(sqrt_N,sqrt_N))
                rho0 = Qobj(sp.csr_matrix(([1],([row_idx],[col_idx])), shape=(sqrt_N,sqrt_N), dtype=complex))
                output = mesolve(H, rho0, tlist, [], [], args, options, _safe_mode=False)
                for k, t in enumerate(tlist):
                    u[:, n, k] = mat2vec(output.states[k].full()).T
            progress_bar.finished()

    else:
        # calculate the propagator for the vector representation of the
        # density matrix (a superoperator propagator)
        unitary_mode = 'single'
        N = H0.shape[0]
        dims = [H0.dims, H0.dims]

        u = np.zeros([N * N, N * N, len(tlist)], dtype=complex)
        
        if parallel:
            output = parallel_map(_parallel_mesolve,range(N * N),
                    task_args=(N,H,tlist,c_op_list,args,options),
                    progress_bar=progress_bar, num_cpus=num_cpus)
            for n in range(N * N):
                for k, t in enumerate(tlist):
                    u[:, n, k] = mat2vec(output[n].states[k].full()).T
        else:
            progress_bar.start(N * N)
            for n in range(N * N):
                progress_bar.update(n)
                col_idx, row_idx = np.unravel_index(n,(N,N))
                rho0 = Qobj(sp.csr_matrix(([1],([row_idx],[col_idx])), shape=(N,N), dtype=complex))
                output = mesolve(H, rho0, tlist, c_op_list, [], args, options, _safe_mode=False)
                for k, t in enumerate(tlist):
                    u[:, n, k] = mat2vec(output.states[k].full()).T
            progress_bar.finished()

    if len(tlist) == 2:
        if unitary_mode == 'batch':
            return Qobj(u[-1], dims=dims)
        else:
            return Qobj(u[:, :, 1], dims=dims)
    else:
        if unitary_mode == 'batch':
            return np.array([Qobj(u[k], dims=dims) for k in range(len(tlist))], dtype=object)
        else:
            return np.array([Qobj(u[:, :, k], dims=dims) for k in range(len(tlist))], dtype=object)
コード例 #46
0
ファイル: mesolve.py プロジェクト: wa4557/qutip
def _mesolve_list_str_td(H_list, rho0, tlist, c_list, e_ops, args, opt, progress_bar):
    """
    Internal function for solving the master equation. See mesolve for usage.
    """

    if debug:
        print(inspect.stack()[0][3])

    #
    # check initial state: must be a density matrix
    #
    if isket(rho0):
        rho0 = rho0 * rho0.dag()

    #
    # construct liouvillian
    #
    Lconst = 0

    Ldata = []
    Linds = []
    Lptrs = []
    Lcoeff = []

    # loop over all hamiltonian terms, convert to superoperator form and
    # add the data of sparse matrix representation to
    for h_spec in H_list:

        if isinstance(h_spec, Qobj):
            h = h_spec

            if isoper(h):
                Lconst += -1j * (spre(h) - spost(h))
            elif issuper(h):
                Lconst += h
            else:
                raise TypeError(
                    "Incorrect specification of time-dependent "
                    + "Hamiltonian (expected operator or "
                    + "superoperator)"
                )

        elif isinstance(h_spec, list):
            h = h_spec[0]
            h_coeff = h_spec[1]

            if isoper(h):
                L = -1j * (spre(h) - spost(h))
            elif issuper(h):
                L = h
            else:
                raise TypeError(
                    "Incorrect specification of time-dependent "
                    + "Hamiltonian (expected operator or "
                    + "superoperator)"
                )

            Ldata.append(L.data.data)
            Linds.append(L.data.indices)
            Lptrs.append(L.data.indptr)
            Lcoeff.append(h_coeff)

        else:
            raise TypeError("Incorrect specification of time-dependent " + "Hamiltonian (expected string format)")

    # loop over all collapse operators
    for c_spec in c_list:

        if isinstance(c_spec, Qobj):
            c = c_spec

            if isoper(c):
                cdc = c.dag() * c
                Lconst += spre(c) * spost(c.dag()) - 0.5 * spre(cdc) - 0.5 * spost(cdc)
            elif issuper(c):
                Lconst += c
            else:
                raise TypeError(
                    "Incorrect specification of time-dependent "
                    + "Liouvillian (expected operator or "
                    + "superoperator)"
                )

        elif isinstance(c_spec, list):
            c = c_spec[0]
            c_coeff = c_spec[1]

            if isoper(c):
                cdc = c.dag() * c
                L = spre(c) * spost(c.dag()) - 0.5 * spre(cdc) - 0.5 * spost(cdc)
                c_coeff = "(" + c_coeff + ")**2"
            elif issuper(c):
                L = c
            else:
                raise TypeError(
                    "Incorrect specification of time-dependent "
                    + "Liouvillian (expected operator or "
                    + "superoperator)"
                )

            Ldata.append(L.data.data)
            Linds.append(L.data.indices)
            Lptrs.append(L.data.indptr)
            Lcoeff.append(c_coeff)

        else:
            raise TypeError(
                "Incorrect specification of time-dependent " + "collapse operators (expected string format)"
            )

    # add the constant part of the lagrangian
    if Lconst != 0:
        Ldata.append(Lconst.data.data)
        Linds.append(Lconst.data.indices)
        Lptrs.append(Lconst.data.indptr)
        Lcoeff.append("1.0")

    # the total number of liouvillian terms (hamiltonian terms +
    # collapse operators)
    n_L_terms = len(Ldata)

    #
    # setup ode args string: we expand the list Ldata, Linds and Lptrs into
    # and explicit list of parameters
    #
    string_list = []
    for k in range(n_L_terms):
        string_list.append("Ldata[%d], Linds[%d], Lptrs[%d]" % (k, k, k))
    for name, value in args.items():
        if isinstance(value, np.ndarray):
            string_list.append(name)
        else:
            string_list.append(str(value))
    parameter_string = ",".join(string_list)

    #
    # generate and compile new cython code if necessary
    #
    if not opt.rhs_reuse or config.tdfunc is None:
        if opt.rhs_filename is None:
            config.tdname = "rhs" + str(os.getpid()) + str(config.cgen_num)
        else:
            config.tdname = opt.rhs_filename
        cgen = Codegen(h_terms=n_L_terms, h_tdterms=Lcoeff, args=args, config=config)
        cgen.generate(config.tdname + ".pyx")

        code = compile("from " + config.tdname + " import cy_td_ode_rhs", "<string>", "exec")
        exec(code, globals())
        config.tdfunc = cy_td_ode_rhs

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full()).ravel()
    r = scipy.integrate.ode(config.tdfunc)
    r.set_integrator(
        "zvode",
        method=opt.method,
        order=opt.order,
        atol=opt.atol,
        rtol=opt.rtol,
        nsteps=opt.nsteps,
        first_step=opt.first_step,
        min_step=opt.min_step,
        max_step=opt.max_step,
    )
    r.set_initial_value(initial_vector, tlist[0])
    code = compile("r.set_f_params(" + parameter_string + ")", "<string>", "exec")

    exec(code, locals(), args)

    #
    # call generic ODE code
    #
    return _generic_ode_solve(r, rho0, tlist, e_ops, opt, progress_bar)
コード例 #47
0
ファイル: propagator.py プロジェクト: yipk2/qutip
def propagator(H,
               t,
               c_op_list,
               args=None,
               options=None,
               sparse=False,
               progress_bar=None):
    """
    Calculate the propagator U(t) for the density matrix or wave function such
    that :math:`\psi(t) = U(t)\psi(0)` or
    :math:`\\rho_{\mathrm vec}(t) = U(t) \\rho_{\mathrm vec}(0)`
    where :math:`\\rho_{\mathrm vec}` is the vector representation of the
    density matrix.

    Parameters
    ----------
    H : qobj or list
        Hamiltonian as a Qobj instance of a nested list of Qobjs and
        coefficients in the list-string or list-function format for
        time-dependent Hamiltonians (see description in :func:`qutip.mesolve`).

    t : float or array-like
        Time or list of times for which to evaluate the propagator.

    c_op_list : list
        List of qobj collapse operators.

    args : list/array/dictionary
        Parameters to callback functions for time-dependent Hamiltonians and
        collapse operators.

    options : :class:`qutip.Options`
        with options for the ODE solver.

    progress_bar: BaseProgressBar
        Optional instance of BaseProgressBar, or a subclass thereof, for
        showing the progress of the simulation. By default no progress bar
        is used, and if set to True a TextProgressBar will be used.

    Returns
    -------
     a : qobj
        Instance representing the propagator :math:`U(t)`.

    """

    if progress_bar is None:
        progress_bar = BaseProgressBar()
    elif progress_bar is True:
        progress_bar = TextProgressBar()

    if options is None:
        options = Options()
        options.rhs_reuse = True
        rhs_clear()

    if isinstance(t, (int, float, np.integer, np.floating)):
        tlist = [0, t]
    else:
        tlist = t

    if isinstance(
            H,
        (types.FunctionType, types.BuiltinFunctionType, functools.partial)):
        H0 = H(0.0, args)
    elif isinstance(H, list):
        H0 = H[0][0] if isinstance(H[0], list) else H[0]
    else:
        H0 = H

    if len(c_op_list) == 0 and H0.isoper:
        # calculate propagator for the wave function

        N = H0.shape[0]
        dims = H0.dims
        u = np.zeros([N, N, len(tlist)], dtype=complex)

        progress_bar.start(N)
        for n in range(0, N):
            progress_bar.update(n)
            psi0 = basis(N, n)
            output = sesolve(H, psi0, tlist, [], args, options)
            for k, t in enumerate(tlist):
                u[:, n, k] = output.states[k].full().T
        progress_bar.finished()

        # todo: evolving a batch of wave functions:
        # psi_0_list = [basis(N, n) for n in range(N)]
        # psi_t_list = mesolve(H, psi_0_list, [0, t], [], [], args, options)
        # for n in range(0, N):
        #    u[:,n] = psi_t_list[n][1].full().T

    elif len(c_op_list) == 0 and H0.issuper:
        # calculate the propagator for the vector representation of the
        # density matrix (a superoperator propagator)

        N = H0.shape[0]
        dims = H0.dims

        u = np.zeros([N, N, len(tlist)], dtype=complex)

        progress_bar.start(N)
        for n in range(0, N):
            progress_bar.update(n)
            psi0 = basis(N, n)
            rho0 = Qobj(vec2mat(psi0.full()))
            output = mesolve(H, rho0, tlist, [], [], args, options)
            for k, t in enumerate(tlist):
                u[:, n, k] = mat2vec(output.states[k].full()).T
        progress_bar.finished()

    else:
        # calculate the propagator for the vector representation of the
        # density matrix (a superoperator propagator)

        N = H0.shape[0]
        dims = [H0.dims, H0.dims]

        u = np.zeros([N * N, N * N, len(tlist)], dtype=complex)

        if sparse:
            progress_bar.start(N * N)
            for n in range(N * N):
                progress_bar.update(n)
                psi0 = basis(N * N, n)
                psi0.dims = [dims[0], 1]
                rho0 = vector_to_operator(psi0)
                output = mesolve(H, rho0, tlist, c_op_list, [], args, options)
                for k, t in enumerate(tlist):
                    u[:, n, k] = operator_to_vector(
                        output.states[k]).full(squeeze=True)
            progress_bar.finished()

        else:
            progress_bar.start(N * N)
            for n in range(N * N):
                progress_bar.update(n)
                psi0 = basis(N * N, n)
                rho0 = Qobj(vec2mat(psi0.full()))
                output = mesolve(H, rho0, tlist, c_op_list, [], args, options)
                for k, t in enumerate(tlist):
                    u[:, n, k] = mat2vec(output.states[k].full()).T
            progress_bar.finished()

    if len(tlist) == 2:
        return Qobj(u[:, :, 1], dims=dims)
    else:
        return [Qobj(u[:, :, k], dims=dims) for k in range(len(tlist))]
コード例 #48
0
ファイル: mesolve.py プロジェクト: wa4557/qutip
def _mesolve_list_td(H_func, rho0, tlist, c_op_list, e_ops, args, opt, progress_bar):
    """
    Evolve the density matrix using an ODE solver with time dependent
    Hamiltonian.
    """

    if debug:
        print(inspect.stack()[0][3])

    #
    # check initial state
    #
    if isket(rho0):
        # if initial state is a ket and no collapse operator where given,
        # fall back on the unitary schrodinger equation solver
        if len(c_op_list) == 0:
            return _sesolve_list_td(H_func, rho0, tlist, e_ops, args, opt, progress_bar)

        # Got a wave function as initial state: convert to density matrix.
        rho0 = ket2dm(rho0)

    #
    # construct liouvillian
    #
    if len(H_func) != 2:
        raise TypeError("Time-dependent Hamiltonian list must have two terms.")
    if not isinstance(H_func[0], (list, np.ndarray)) or len(H_func[0]) <= 1:
        raise TypeError("Time-dependent Hamiltonians must be a list " + "with two or more terms")
    if (not isinstance(H_func[1], (list, np.ndarray))) or (len(H_func[1]) != (len(H_func[0]) - 1)):
        raise TypeError(
            "Time-dependent coefficients must be list with "
            + "length N-1 where N is the number of "
            + "Hamiltonian terms."
        )

    if opt.rhs_reuse and config.tdfunc is None:
        rhs_generate(H_func, args)

    lenh = len(H_func[0])
    if opt.tidy:
        H_func[0] = [(H_func[0][k]).tidyup() for k in range(lenh)]
    L_func = [[liouvillian(H_func[0][0], c_op_list)], H_func[1]]
    for m in range(1, lenh):
        L_func[0].append(liouvillian(H_func[0][m], []))

    # create data arrays for time-dependent RHS function
    Ldata = [L_func[0][k].data.data for k in range(lenh)]
    Linds = [L_func[0][k].data.indices for k in range(lenh)]
    Lptrs = [L_func[0][k].data.indptr for k in range(lenh)]
    # setup ode args string
    string = ""
    for k in range(lenh):
        string += "Ldata[%d], Linds[%d], Lptrs[%d]," % (k, k, k)

    if args:
        td_consts = args.items()
        for elem in td_consts:
            string += str(elem[1])
            if elem != td_consts[-1]:
                string += ","

    # run code generator
    if not opt.rhs_reuse or config.tdfunc is None:
        if opt.rhs_filename is None:
            config.tdname = "rhs" + str(os.getpid()) + str(config.cgen_num)
        else:
            config.tdname = opt.rhs_filename
        cgen = Codegen(h_terms=n_L_terms, h_tdterms=Lcoeff, args=args, config=config)
        cgen.generate(config.tdname + ".pyx")

        code = compile("from " + config.tdname + " import cy_td_ode_rhs", "<string>", "exec")
        exec(code, globals())
        config.tdfunc = cy_td_ode_rhs

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full()).ravel()
    r = scipy.integrate.ode(config.tdfunc)
    r.set_integrator(
        "zvode",
        method=opt.method,
        order=opt.order,
        atol=opt.atol,
        rtol=opt.rtol,
        nsteps=opt.nsteps,
        first_step=opt.first_step,
        min_step=opt.min_step,
        max_step=opt.max_step,
    )
    r.set_initial_value(initial_vector, tlist[0])
    code = compile("r.set_f_params(" + string + ")", "<string>", "exec")
    exec(code)

    #
    # call generic ODE code
    #
    return _generic_ode_solve(r, rho0, tlist, e_ops, opt, progress_bar)
コード例 #49
0
ファイル: propagator.py プロジェクト: tmng/qutip
def propagator(H, t, c_op_list, args=None, options=None, sparse=False):
    """
    Calculate the propagator U(t) for the density matrix or wave function such
    that :math:`\psi(t) = U(t)\psi(0)` or
    :math:`\\rho_{\mathrm vec}(t) = U(t) \\rho_{\mathrm vec}(0)`
    where :math:`\\rho_{\mathrm vec}` is the vector representation of the
    density matrix.

    Parameters
    ----------
    H : qobj or list
        Hamiltonian as a Qobj instance of a nested list of Qobjs and
        coefficients in the list-string or list-function format for
        time-dependent Hamiltonians (see description in :func:`qutip.mesolve`).

    t : float or array-like
        Time or list of times for which to evaluate the propagator.

    c_op_list : list
        List of qobj collapse operators.

    args : list/array/dictionary
        Parameters to callback functions for time-dependent Hamiltonians and
        collapse operators.

    options : :class:`qutip.Options`
        with options for the ODE solver.

    Returns
    -------
     a : qobj
        Instance representing the propagator :math:`U(t)`.

    """

    if options is None:
        options = Options()
        options.rhs_reuse = True
        rhs_clear()

    if isinstance(t, (int, float, np.integer, np.floating)):
        tlist = [0, t]
    else:
        tlist = t

    if isinstance(H, (types.FunctionType, types.BuiltinFunctionType,
                      functools.partial)):
        H0 = H(0.0, args)
    elif isinstance(H, list):
        H0 = H[0][0] if isinstance(H[0], list) else H[0]
    else:
        H0 = H

    if len(c_op_list) == 0 and H0.isoper:
        # calculate propagator for the wave function

        N = H0.shape[0]
        dims = H0.dims
        u = np.zeros([N, N, len(tlist)], dtype=complex)

        for n in range(0, N):
            psi0 = basis(N, n)
            output = sesolve(H, psi0, tlist, [], args, options)
            for k, t in enumerate(tlist):
                u[:, n, k] = output.states[k].full().T

        # todo: evolving a batch of wave functions:
        # psi_0_list = [basis(N, n) for n in range(N)]
        # psi_t_list = mesolve(H, psi_0_list, [0, t], [], [], args, options)
        # for n in range(0, N):
        #    u[:,n] = psi_t_list[n][1].full().T

    elif len(c_op_list) == 0 and H0.issuper:
        # calculate the propagator for the vector representation of the
        # density matrix (a superoperator propagator)

        N = H0.shape[0]
        dims = H0.dims

        u = np.zeros([N, N, len(tlist)], dtype=complex)

        for n in range(0, N):
            psi0 = basis(N, n)
            rho0 = Qobj(vec2mat(psi0.full()))
            output = mesolve(H, rho0, tlist, [], [], args, options)
            for k, t in enumerate(tlist):
                u[:, n, k] = mat2vec(output.states[k].full()).T

    else:
        # calculate the propagator for the vector representation of the
        # density matrix (a superoperator propagator)

        N = H0.shape[0]
        dims = [H0.dims, H0.dims]

        u = np.zeros([N * N, N * N, len(tlist)], dtype=complex)

        if sparse:
            for n in range(N * N):
                psi0 = basis(N * N, n)
                psi0.dims = [dims[0], 1]
                rho0 = vector_to_operator(psi0)
                output = mesolve(H, rho0, tlist, c_op_list, [], args, options)
                for k, t in enumerate(tlist):
                    u[:, n, k] = operator_to_vector(
                        output.states[k]).full(squeeze=True)

        else:
            for n in range(N * N):
                psi0 = basis(N * N, n)
                rho0 = Qobj(vec2mat(psi0.full()))
                output = mesolve(H, rho0, tlist, c_op_list, [], args, options)
                for k, t in enumerate(tlist):
                    u[:, n, k] = mat2vec(output.states[k].full()).T

    if len(tlist) == 2:
        return Qobj(u[:, :, 1], dims=dims)
    else:
        return [Qobj(u[:, :, k], dims=dims) for k in range(len(tlist))]
コード例 #50
0
ファイル: bloch_redfield.py プロジェクト: avandeursen/qutip
def _td_brmesolve(H,
                  psi0,
                  tlist,
                  a_ops=[],
                  e_ops=[],
                  c_ops=[],
                  use_secular=True,
                  tol=qset.atol,
                  options=None,
                  progress_bar=None,
                  _safe_mode=True):

    if isket(psi0):
        rho0 = ket2dm(psi0)
    else:
        rho0 = psi0
    nrows = rho0.shape[0]

    H_terms = []
    H_td_terms = []
    H_obj = []
    A_terms = []
    A_td_terms = []
    C_terms = []
    C_td_terms = []
    C_obj = []
    spline_count = [0, 0]

    if isinstance(H, Qobj):
        H_terms.append(H.full('f'))
        H_td_terms.append('1')
    else:
        for kk, h in enumerate(H):
            if isinstance(h, Qobj):
                H_terms.append(h.full('f'))
                H_td_terms.append('1')
            elif isinstance(h, list):
                H_terms.append(h[0].full('f'))
                if isinstance(h[1], Cubic_Spline):
                    H_obj.append(h[1].coeffs)
                    spline_count[0] += 1
                H_td_terms.append(h[1])
            else:
                raise Exception('Invalid Hamiltonian specifiction.')

    for kk, c in enumerate(c_ops):
        if isinstance(c, Qobj):
            C_terms.append(c.full('f'))
            C_td_terms.append('1')
        elif isinstance(c, list):
            C_terms.append(c[0].full('f'))
            if isinstance(c[1], Cubic_Spline):
                C_obj.append(c[1].coeffs)
                spline_count[0] += 1
            C_td_terms.append(c[1])
        else:
            raise Exception('Invalid collape operator specifiction.')

    for kk, a in enumerate(a_ops):
        if isinstance(a, list):
            A_terms.append(a[0].full('f'))
            A_td_terms.append(a[1])
            if isinstance(a[1], tuple):
                if not len(a[1]) == 2:
                    raise Exception('Tuple must be len=2.')
                if isinstance(a[1][0], Cubic_Spline):
                    spline_count[1] += 1
                if isinstance(a[1][1], Cubic_Spline):
                    spline_count[1] += 1
        else:
            raise Exception('Invalid bath-coupling specifiction.')

    string_list = []
    for kk, _ in enumerate(H_td_terms):
        string_list.append("H_terms[{0}]".format(kk))
    for kk, _ in enumerate(H_obj):
        string_list.append("H_obj[{0}]".format(kk))
    for kk, _ in enumerate(C_td_terms):
        string_list.append("C_terms[{0}]".format(kk))
    for kk, _ in enumerate(C_obj):
        string_list.append("C_obj[{0}]".format(kk))
    for kk, _ in enumerate(A_td_terms):
        string_list.append("A_terms[{0}]".format(kk))
    #Add nrows to parameters
    string_list.append('nrows')
    parameter_string = ",".join(string_list)

    #
    # generate and compile new cython code if necessary
    #
    if not options.rhs_reuse or config.tdfunc is None:
        if options.rhs_filename is None:
            config.tdname = "rhs" + str(os.getpid()) + str(config.cgen_num)
        else:
            config.tdname = opt.rhs_filename
        cgen = BR_Codegen(
            h_terms=len(H_terms),
            h_td_terms=H_td_terms,
            h_obj=H_obj,
            c_terms=len(C_terms),
            c_td_terms=C_td_terms,
            c_obj=C_obj,
            a_terms=len(A_terms),
            a_td_terms=A_td_terms,
            spline_count=spline_count,
            config=config,
            sparse=False,
            use_secular=use_secular,
            use_openmp=options.use_openmp,
            omp_thresh=qset.openmp_thresh if qset.has_openmp else None,
            omp_threads=options.num_cpus,
            atol=tol)

        cgen.generate(config.tdname + ".pyx")
        code = compile('from ' + config.tdname + ' import cy_td_ode_rhs',
                       '<string>', 'exec')
        exec(code, globals())
        config.tdfunc = cy_td_ode_rhs

    initial_vector = mat2vec(rho0.full()).ravel()

    _ode = scipy.integrate.ode(config.tdfunc)
    code = compile('_ode.set_f_params(' + parameter_string + ')', '<string>',
                   'exec')
    _ode.set_integrator('zvode',
                        method=options.method,
                        order=options.order,
                        atol=options.atol,
                        rtol=options.rtol,
                        nsteps=options.nsteps,
                        first_step=options.first_step,
                        min_step=options.min_step,
                        max_step=options.max_step)
    _ode.set_initial_value(initial_vector, tlist[0])
    exec(code, locals())

    #
    # prepare output array
    #
    n_tsteps = len(tlist)
    e_sops_data = []

    output = Result()
    output.solver = "brmesolve"
    output.times = tlist

    if options.store_states:
        output.states = []

    if isinstance(e_ops, types.FunctionType):
        n_expt_op = 0
        expt_callback = True

    elif isinstance(e_ops, list):
        n_expt_op = len(e_ops)
        expt_callback = False

        if n_expt_op == 0:
            # fall back on storing states
            output.states = []
            options.store_states = True
        else:
            output.expect = []
            output.num_expect = n_expt_op
            for op in e_ops:
                e_sops_data.append(spre(op).data)
                if op.isherm:
                    output.expect.append(np.zeros(n_tsteps))
                else:
                    output.expect.append(np.zeros(n_tsteps, dtype=complex))

    else:
        raise TypeError("Expectation parameter must be a list or a function")

    #
    # start evolution
    #
    progress_bar.start(n_tsteps)

    rho = Qobj(rho0)

    dt = np.diff(tlist)
    for t_idx, t in enumerate(tlist):
        progress_bar.update(t_idx)

        if not _ode.successful():
            raise Exception("ODE integration error: Try to increase "
                            "the allowed number of substeps by increasing "
                            "the nsteps parameter in the Options class.")

        if options.store_states or expt_callback:
            rho.data = dense2D_to_fastcsr_fmode(vec2mat(_ode.y), rho.shape[0],
                                                rho.shape[1])

            if options.store_states:
                output.states.append(Qobj(rho, isherm=True))

            if expt_callback:
                # use callback method
                e_ops(t, rho)

        for m in range(n_expt_op):
            if output.expect[m].dtype == complex:
                output.expect[m][t_idx] = expect_rho_vec(
                    e_sops_data[m], _ode.y, 0)
            else:
                output.expect[m][t_idx] = expect_rho_vec(
                    e_sops_data[m], _ode.y, 1)

        if t_idx < n_tsteps - 1:
            _ode.integrate(_ode.t + dt[t_idx])

    progress_bar.finished()

    if (not options.rhs_reuse) and (config.tdname is not None):
        _cython_build_cleanup(config.tdname)

    if options.store_final_state:
        rho.data = dense2D_to_fastcsr_fmode(vec2mat(_ode.y), rho.shape[0],
                                            rho.shape[1])
        output.final_state = Qobj(rho, dims=rho0.dims, isherm=True)

    return output
コード例 #51
0
ファイル: stochastic.py プロジェクト: zaguros/analysis
def smesolve_generic(H, rho0, tlist, c_ops, e_ops,
                     rhs, d1, d2, ntraj, nsubsteps):
    """
    internal

    .. note::

        Experimental.

    """
    if debug:
        print(inspect.stack()[0][3])

    N_store = len(tlist)
    N_substeps = nsubsteps
    N = N_store * N_substeps
    dt = (tlist[1] - tlist[0]) / N_substeps

    print("N = %d. dt=%.2e" % (N, dt))

    data = Odedata()

    data.expect = np.zeros((len(e_ops), N_store), dtype=complex)

    # pre-compute collapse operator combinations that are commonly needed
    # when evaluating the RHS of stochastic master equations
    A_ops = []
    for c_idx, c in enumerate(c_ops):

        # xxx: precompute useful operator expressions...
        cdc = c.dag() * c
        Ldt = spre(c) * spost(c.dag()) - 0.5 * spre(cdc) - 0.5 * spost(cdc)
        LdW = spre(c) + spost(c.dag())
        Lm = spre(c) + spost(c.dag())  # currently same as LdW

        A_ops.append([Ldt.data, LdW.data, Lm.data])

    # Liouvillian for the unitary part
    L = -1.0j * (spre(H) - spost(H))
                 # XXX: should we split the ME in stochastic
                                   # and deterministic collapse operators here?

    progress_acc = 0.0
    for n in range(ntraj):

        if debug and (100 * float(n) / ntraj) >= progress_acc:
            print("Progress: %.2f" % (100 * float(n) / ntraj))
            progress_acc += 10.0

        rho_t = mat2vec(rho0.full())

        states_list = _smesolve_single_trajectory(
            L, dt, tlist, N_store, N_substeps,
            rho_t, A_ops, e_ops, data, rhs, d1, d2)

        # if average -> average...
        data.states.append(states_list)

    # average
    data.expect = data.expect / ntraj

    return data
コード例 #52
0
ファイル: propagator.py プロジェクト: partus/qutip
def propagator(H, t, c_op_list, H_args=None, opt=None):
    """
    Calculate the propagator U(t) for the density matrix or wave function such
    that :math:`\psi(t) = U(t)\psi(0)` or
    :math:`\\rho_{\mathrm vec}(t) = U(t) \\rho_{\mathrm vec}(0)`
    where :math:`\\rho_{\mathrm vec}` is the vector representation of the
    density matrix.

    Parameters
    ----------
    H : qobj or list
        Hamiltonian as a Qobj instance of a nested list of Qobjs and
        coefficients in the list-string or list-function format for
        time-dependent Hamiltonians (see description in :func:`qutip.mesolve`).
    t : float or array-like
        Time or list of times for which to evaluate the propagator.
    c_op_list : list
        List of qobj collapse operators.
    H_args : list/array/dictionary
        Parameters to callback functions for time-dependent Hamiltonians.

    Returns
    -------
     a : qobj
        Instance representing the propagator :math:`U(t)`.

    """

    if opt is None:
        opt = Odeoptions()
        opt.rhs_reuse = True

    tlist = [0, t] if isinstance(t, (int, float, np.int64, np.float64)) else t

    if len(c_op_list) == 0:
        # calculate propagator for the wave function

        if isinstance(H, types.FunctionType):
            H0 = H(0.0, H_args)
            N = H0.shape[0]
            dims = H0.dims
        elif isinstance(H, list):
            H0 = H[0][0] if isinstance(H[0], list) else H[0]
            N = H0.shape[0]
            dims = H0.dims
        else:
            N = H.shape[0]
            dims = H.dims

        u = np.zeros([N, N, len(tlist)], dtype=complex)

        for n in range(0, N):
            psi0 = basis(N, n)
            output = mesolve(H, psi0, tlist, [], [], H_args, opt)
            for k, t in enumerate(tlist):
                u[:, n, k] = output.states[k].full().T

        # todo: evolving a batch of wave functions:
        #psi_0_list = [basis(N, n) for n in range(N)]
        #psi_t_list = mesolve(H, psi_0_list, [0, t], [], [], H_args, opt)
        #for n in range(0, N):
        #    u[:,n] = psi_t_list[n][1].full().T

    else:
        # calculate the propagator for the vector representation of the
        # density matrix (a superoperator propagator)

        if isinstance(H, types.FunctionType):
            H0 = H(0.0, H_args)
            N = H0.shape[0]
            dims = [H0.dims, H0.dims]
        elif isinstance(H, list):
            H0 = H[0][0] if isinstance(H[0], list) else H[0]
            N = H0.shape[0]
            dims = [H0.dims, H0.dims]
        else:
            N = H.shape[0]
            dims = [H.dims, H.dims]

        u = np.zeros([N * N, N * N, len(tlist)], dtype=complex)

        for n in range(0, N * N):
            psi0 = basis(N * N, n)
            rho0 = Qobj(vec2mat(psi0.full()))
            output = mesolve(H, rho0, tlist, c_op_list, [], H_args, opt)
            for k, t in enumerate(tlist):
                u[:, n, k] = mat2vec(output.states[k].full()).T

    if len(tlist) == 2:
        return Qobj(u[:, :, 1], dims=dims)
    else:
        return [Qobj(u[:, :, k], dims=dims) for k in range(len(tlist))]
コード例 #53
0
def propagator(H, t, c_op_list, args=None, options=None):
    """
    Calculate the propagator U(t) for the density matrix or wave function such
    that :math:`\psi(t) = U(t)\psi(0)` or
    :math:`\\rho_{\mathrm vec}(t) = U(t) \\rho_{\mathrm vec}(0)`
    where :math:`\\rho_{\mathrm vec}` is the vector representation of the
    density matrix.

    Parameters
    ----------
    H : qobj or list
        Hamiltonian as a Qobj instance of a nested list of Qobjs and
        coefficients in the list-string or list-function format for
        time-dependent Hamiltonians (see description in :func:`qutip.mesolve`).

    t : float or array-like
        Time or list of times for which to evaluate the propagator.

    c_op_list : list
        List of qobj collapse operators.

    args : list/array/dictionary
        Parameters to callback functions for time-dependent Hamiltonians and
        collapse operators.

    options : :class:`qutip.Odeoptions`
        with options for the ODE solver.

    Returns
    -------
     a : qobj
        Instance representing the propagator :math:`U(t)`.

    """

    if options is None:
        options = Odeoptions()
        options.rhs_reuse = True
        rhs_clear()
    elif options.rhs_reuse:
        msg = ("propagator is using previously defined rhs " +
               "function (options.rhs_reuse = True)")
        warnings.warn(msg)

    tlist = [0, t] if isinstance(t, (int, float, np.int64, np.float64)) else t

    if len(c_op_list) == 0:
        # calculate propagator for the wave function

        if isinstance(H, types.FunctionType):
            H0 = H(0.0, args)
            N = H0.shape[0]
            dims = H0.dims
        elif isinstance(H, list):
            H0 = H[0][0] if isinstance(H[0], list) else H[0]
            N = H0.shape[0]
            dims = H0.dims
        else:
            N = H.shape[0]
            dims = H.dims

        u = np.zeros([N, N, len(tlist)], dtype=complex)

        for n in range(0, N):
            psi0 = basis(N, n)
            output = sesolve(H, psi0, tlist, [], args, options)
            for k, t in enumerate(tlist):
                u[:, n, k] = output.states[k].full().T

        # todo: evolving a batch of wave functions:
        # psi_0_list = [basis(N, n) for n in range(N)]
        # psi_t_list = mesolve(H, psi_0_list, [0, t], [], [], args, options)
        # for n in range(0, N):
        #    u[:,n] = psi_t_list[n][1].full().T

    else:
        # calculate the propagator for the vector representation of the
        # density matrix (a superoperator propagator)

        if isinstance(H, types.FunctionType):
            H0 = H(0.0, args)
            N = H0.shape[0]
            dims = [H0.dims, H0.dims]
        elif isinstance(H, list):
            H0 = H[0][0] if isinstance(H[0], list) else H[0]
            N = H0.shape[0]
            dims = [H0.dims, H0.dims]
        else:
            N = H.shape[0]
            dims = [H.dims, H.dims]

        u = np.zeros([N * N, N * N, len(tlist)], dtype=complex)

        for n in range(0, N * N):
            psi0 = basis(N * N, n)
            rho0 = Qobj(vec2mat(psi0.full()))
            output = mesolve(H, rho0, tlist, c_op_list, [], args, options)
            for k, t in enumerate(tlist):
                u[:, n, k] = mat2vec(output.states[k].full()).T

    if len(tlist) == 2:
        return Qobj(u[:, :, 1], dims=dims)
    else:
        return [Qobj(u[:, :, k], dims=dims) for k in range(len(tlist))]
コード例 #54
0
ファイル: floquet.py プロジェクト: vamsi1905/qutip
def floquet_markov_mesolve(R,
                           ekets,
                           rho0,
                           tlist,
                           e_ops,
                           f_modes_table=None,
                           options=None,
                           floquet_basis=True):
    """
    Solve the dynamics for the system using the Floquet-Markov master equation.
    """

    if options is None:
        opt = Options()
    else:
        opt = options

    if opt.tidy:
        R.tidyup()

    #
    # check initial state
    #
    if isket(rho0):
        # Got a wave function as initial state: convert to density matrix.
        rho0 = ket2dm(rho0)

    #
    # prepare output array
    #
    n_tsteps = len(tlist)
    dt = tlist[1] - tlist[0]

    output = Result()
    output.solver = "fmmesolve"
    output.times = tlist

    if isinstance(e_ops, FunctionType):
        n_expt_op = 0
        expt_callback = True

    elif isinstance(e_ops, list):

        n_expt_op = len(e_ops)
        expt_callback = False

        if n_expt_op == 0:
            output.states = []
        else:
            if not f_modes_table:
                raise TypeError("The Floquet mode table has to be provided " +
                                "when requesting expectation values.")

            output.expect = []
            output.num_expect = n_expt_op
            for op in e_ops:
                if op.isherm:
                    output.expect.append(np.zeros(n_tsteps))
                else:
                    output.expect.append(np.zeros(n_tsteps, dtype=complex))

    else:
        raise TypeError("Expectation parameter must be a list or a function")

    #
    # transform the initial density matrix to the eigenbasis: from
    # computational basis to the floquet basis
    #
    if ekets is not None:
        rho0 = rho0.transform(ekets)

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full())
    r = scipy.integrate.ode(cy_ode_rhs)
    r.set_f_params(R.data.data, R.data.indices, R.data.indptr)
    r.set_integrator('zvode',
                     method=opt.method,
                     order=opt.order,
                     atol=opt.atol,
                     rtol=opt.rtol,
                     max_step=opt.max_step)
    r.set_initial_value(initial_vector, tlist[0])

    #
    # start evolution
    #
    rho = Qobj(rho0)

    t_idx = 0
    for t in tlist:
        if not r.successful():
            break

        rho = Qobj(vec2mat(r.y), rho0.dims, rho0.shape)

        if expt_callback:
            # use callback method
            if floquet_basis:
                e_ops(t, Qobj(rho))
            else:
                f_modes_table_t, T = f_modes_table
                f_modes_t = floquet_modes_t_lookup(f_modes_table_t, t, T)
                e_ops(t, Qobj(rho).transform(f_modes_t, True))
        else:
            # calculate all the expectation values, or output rho if
            # no operators
            if n_expt_op == 0:
                if floquet_basis:
                    output.states.append(Qobj(rho))
                else:
                    f_modes_table_t, T = f_modes_table
                    f_modes_t = floquet_modes_t_lookup(f_modes_table_t, t, T)
                    output.states.append(Qobj(rho).transform(f_modes_t, True))
            else:
                f_modes_table_t, T = f_modes_table
                f_modes_t = floquet_modes_t_lookup(f_modes_table_t, t, T)
                for m in range(0, n_expt_op):
                    output.expect[m][t_idx] = \
                        expect(e_ops[m], rho.transform(f_modes_t, False))

        r.integrate(r.t + dt)
        t_idx += 1

    return output
コード例 #55
0
ファイル: countstat.py プロジェクト: zzpwahaha/qutip
def countstat_current_noise(L,
                            c_ops,
                            wlist=None,
                            rhoss=None,
                            J_ops=None,
                            sparse=True,
                            method='direct'):
    """
    Compute the cross-current noise spectrum for a list of collapse operators
    `c_ops` corresponding to monitored currents, given the system
    Liouvillian `L`. The current collapse operators `c_ops` should be part
    of the dissipative processes in `L`, but the `c_ops` given here does not
    necessarily need to be all collapse operators contributing to dissipation
    in the Liouvillian. Optionally, the steadystate density matrix `rhoss`
    and the current operators `J_ops` correpsonding to the current collapse 
    operators `c_ops` can also be specified. If either of
    `rhoss` and `J_ops` are omitted, they will be computed internally.
    'wlist' is an optional list of frequencies at which to evaluate the noise 
    spectrum.  
    
    Note:
    The default method is a direct solution using dense matrices, as sparse 
    matrix methods fail for some examples of small systems.
    For larger systems it is reccomended to use the sparse solver
    with the direct method, as it avoids explicit calculation of the
    pseudo-inverse, as described in page 67 of "Electrons in nanostructures"
    C. Flindt, PhD Thesis, available online:
    http://orbit.dtu.dk/fedora/objects/orbit:82314/datastreams/file_4732600/content
    
    Parameters
    ----------

    L : :class:`qutip.Qobj`
        Qobj representing the system Liouvillian.

    c_ops : array / list
        List of current collapse operators.

    rhoss : :class:`qutip.Qobj` (optional)
        The steadystate density matrix corresponding the system Liouvillian
        `L`.
        
    wlist : array / list (optional)
        List of frequencies at which to evaluate (if none are given, evaluates 
        at zero frequency)

    J_ops : array / list (optional)
        List of current superoperators.

    sparse : bool
        Flag that indicates whether to use sparse or dense matrix methods when
        computing the pseudo inverse. Default is false, as sparse solvers
        can fail for small systems. For larger systems the sparse solvers
        are reccomended. 
        
        
    Returns
    --------
    I, S : tuple of arrays
        The currents `I` corresponding to each current collapse operator
        `c_ops` (or, equivalently, each current superopeator `J_ops`) and the
        zero-frequency cross-current correlation `S`.
    """

    if rhoss is None:
        rhoss = steadystate(L, c_ops)

    if J_ops is None:
        J_ops = [sprepost(c, c.dag()) for c in c_ops]

    N = len(J_ops)
    I = np.zeros(N)

    if wlist is None:
        S = np.zeros((N, N, 1))
        wlist = [0.]
    else:
        S = np.zeros((N, N, len(wlist)))

    if sparse == False:
        rhoss_vec = mat2vec(rhoss.full()).ravel()
        for k, w in enumerate(wlist):
            R = pseudo_inverse(L,
                               rhoss=rhoss,
                               w=w,
                               sparse=sparse,
                               method=method)
            for i, Ji in enumerate(J_ops):
                for j, Jj in enumerate(J_ops):
                    if i == j:
                        I[i] = expect_rho_vec(Ji.data, rhoss_vec, 1)
                        S[i, j, k] = I[i]
                    S[i, j, k] -= expect_rho_vec(
                        (Ji * R * Jj + Jj * R * Ji).data, rhoss_vec, 1)
    else:
        if method == "direct":
            N = np.prod(L.dims[0][0])

            rhoss_vec = operator_to_vector(rhoss)

            tr_op = tensor([identity(n) for n in L.dims[0][0]])
            tr_op_vec = operator_to_vector(tr_op)

            Pop = sp.kron(rhoss_vec.data, tr_op_vec.data.T, format='csr')
            Iop = sp.eye(N * N, N * N, format='csr')
            Q = Iop - Pop

            for k, w in enumerate(wlist):

                if w != 0.0:
                    L_temp = 1.0j * w * spre(tr_op) + L
                else:  #At zero frequency some solvers fail for small systems.
                    #Adding a small finite frequency of order 1e-15
                    #helps prevent the solvers from throwing an exception.
                    L_temp = 1.0j * (1e-15) * spre(tr_op) + L

                if not settings.has_mkl:
                    A = L_temp.data.tocsc()
                else:
                    A = L_temp.data.tocsr()
                    A.sort_indices()

                rhoss_vec = mat2vec(rhoss.full()).ravel()

                for j, Jj in enumerate(J_ops):
                    Qj = Q.dot(Jj.data.dot(rhoss_vec))
                    try:
                        if settings.has_mkl:
                            X_rho_vec_j = mkl_spsolve(A, Qj)
                        else:
                            X_rho_vec_j = sp.linalg.splu(
                                A, permc_spec='COLAMD').solve(Qj)
                    except:
                        X_rho_vec_j = sp.linalg.lsqr(A, Qj)[0]
                    for i, Ji in enumerate(J_ops):
                        Qi = Q.dot(Ji.data.dot(rhoss_vec))
                        try:
                            if settings.has_mkl:
                                X_rho_vec_i = mkl_spsolve(A, Qi)
                            else:
                                X_rho_vec_i = sp.linalg.splu(
                                    A, permc_spec='COLAMD').solve(Qi)
                        except:
                            X_rho_vec_i = sp.linalg.lsqr(A, Qi)[0]
                        if i == j:
                            I[i] = expect_rho_vec(Ji.data, rhoss_vec, 1)
                            S[j, i, k] = I[i]

                        S[j, i,
                          k] -= (expect_rho_vec(Jj.data * Q, X_rho_vec_i, 1) +
                                 expect_rho_vec(Ji.data * Q, X_rho_vec_j, 1))

        else:
            rhoss_vec = mat2vec(rhoss.full()).ravel()
            for k, w in enumerate(wlist):

                R = pseudo_inverse(L,
                                   rhoss=rhoss,
                                   w=w,
                                   sparse=sparse,
                                   method=method)

                for i, Ji in enumerate(J_ops):
                    for j, Jj in enumerate(J_ops):
                        if i == j:
                            I[i] = expect_rho_vec(Ji.data, rhoss_vec, 1)
                            S[i, j, k] = I[i]
                        S[i, j, k] -= expect_rho_vec(
                            (Ji * R * Jj + Jj * R * Ji).data, rhoss_vec, 1)
    return I, S
コード例 #56
0
ファイル: floquet.py プロジェクト: niazalikhan87/qutip
def floquet_markov_mesolve(R, ekets, rho0, tlist, e_ops, options=None):
    """
    Solve the dynamics for the system using the Floquet-Markov master equation.   
    """

    if options == None:
        opt = Odeoptions()
    else:
        opt=options

    if opt.tidy:
        R.tidyup()

    #
    # check initial state
    #
    if isket(rho0):
        # Got a wave function as initial state: convert to density matrix.
        rho0 = ket2dm(rho0)
       
    #
    # prepare output array
    # 
    n_tsteps  = len(tlist)
    dt        = tlist[1]-tlist[0]
       
    output = Odedata()
    output.times = tlist
        
    if isinstance(e_ops, FunctionType):
        n_expt_op = 0
        expt_callback = True
        
    elif isinstance(e_ops, list):
  
        n_expt_op = len(e_ops)
        expt_callback = False

        if n_expt_op == 0:
            output.states = []
        else:
            output.expect = []
            output.num_expect = n_expt_op
            for op in e_ops:
                if op.isherm:
                    output.expect.append(np.zeros(n_tsteps))
                else:
                    output.expect.append(np.zeros(n_tsteps,dtype=complex))

    else:
        raise TypeError("Expectation parameter must be a list or a function")


    #
    # transform the initial density matrix and the e_ops opterators to the
    # eigenbasis: from computational basis to the floquet basis
    #
    if ekets != None:
        rho0 = rho0.transform(ekets, True)
        if isinstance(e_ops, list):
            for n in np.arange(len(e_ops)):             # not working
                e_ops[n] = e_ops[n].transform(ekets) #

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho0.full())
    r = scipy.integrate.ode(cyq_ode_rhs)
    r.set_f_params(R.data.data, R.data.indices, R.data.indptr)
    r.set_integrator('zvode', method=opt.method, order=opt.order,
                              atol=opt.atol, rtol=opt.rtol,
                              max_step=opt.max_step)
    r.set_initial_value(initial_vector, tlist[0])

    #
    # start evolution
    #
    rho = Qobj(rho0)

    t_idx = 0
    for t in tlist:
        if not r.successful():
            break;

        rho.data = vec2mat(r.y)

        if expt_callback:
            # use callback method
            e_ops(t, Qobj(rho))
        else:
            # calculate all the expectation values, or output rho if no operators
            if n_expt_op == 0:
                output.states.append(Qobj(rho)) # copy psi/rho
            else:
                for m in range(0, n_expt_op):
                    output.expect[m][t_idx] = expect(e_ops[m], rho) # basis OK?

        r.integrate(r.t + dt)
        t_idx += 1
          
    return output
コード例 #57
0
ファイル: bloch_redfield.py プロジェクト: ajgpitch/qutip
def _td_brmesolve(H, psi0, tlist, a_ops=[], e_ops=[], c_ops=[], args={},
                 use_secular=True, sec_cutoff=0.1,
                 tol=qset.atol, options=None, 
                 progress_bar=None,_safe_mode=True,
                 verbose=False,
                 _prep_time=0):
    
    if isket(psi0):
        rho0 = ket2dm(psi0)
    else:
        rho0 = psi0
    nrows = rho0.shape[0]
    
    H_terms = []
    H_td_terms = []
    H_obj = []
    A_terms = []
    A_td_terms = []
    C_terms = []
    C_td_terms = []
    CA_obj = []
    spline_count = [0,0]
    coupled_ops = []
    coupled_lengths = []
    coupled_spectra = []
    
    if isinstance(H, Qobj):
        H_terms.append(H.full('f'))
        H_td_terms.append('1')
    else: 
        for kk, h in enumerate(H):
            if isinstance(h, Qobj):
                H_terms.append(h.full('f'))
                H_td_terms.append('1')
            elif isinstance(h, list):
                H_terms.append(h[0].full('f'))
                if isinstance(h[1], Cubic_Spline):
                    H_obj.append(h[1].coeffs)
                    spline_count[0] += 1
                H_td_terms.append(h[1])
            else:
                raise Exception('Invalid Hamiltonian specification.')
    
            
    for kk, c in enumerate(c_ops):
        if isinstance(c, Qobj):
            C_terms.append(c.full('f'))
            C_td_terms.append('1')
        elif isinstance(c, list):
            C_terms.append(c[0].full('f'))
            if isinstance(c[1], Cubic_Spline):
                CA_obj.append(c[1].coeffs)
                spline_count[0] += 1
            C_td_terms.append(c[1])
        else:
            raise Exception('Invalid collapse operator specification.')
            
    coupled_offset = 0
    for kk, a in enumerate(a_ops):
        if isinstance(a, list):
            if isinstance(a[0], Qobj):
                A_terms.append(a[0].full('f'))
                A_td_terms.append(a[1])
                if isinstance(a[1], tuple):
                    if not len(a[1])==2:
                       raise Exception('Tuple must be len=2.')
                    if isinstance(a[1][0],Cubic_Spline):
                        spline_count[1] += 1
                    if isinstance(a[1][1],Cubic_Spline):
                        spline_count[1] += 1
            elif isinstance(a[0], tuple):
                if not isinstance(a[1], tuple):
                    raise Exception('Invalid bath-coupling specification.')
                if (len(a[0])+1) != len(a[1]):
                    raise Exception('BR a_ops tuple lengths not compatible.')
                
                coupled_ops.append(kk+coupled_offset)
                coupled_lengths.append(len(a[0]))
                coupled_spectra.append(a[1][0])
                coupled_offset += len(a[0])-1
                if isinstance(a[1][0],Cubic_Spline):
                    spline_count[1] += 1
                
                for nn, _a in enumerate(a[0]):
                    A_terms.append(_a.full('f'))
                    A_td_terms.append(a[1][nn+1])
                    if isinstance(a[1][nn+1],Cubic_Spline):
                        CA_obj.append(a[1][nn+1].coeffs)
                        spline_count[1] += 1
                                
        else:
            raise Exception('Invalid bath-coupling specification.')
            
    
    string_list = []
    for kk,_ in enumerate(H_td_terms):
        string_list.append("H_terms[{0}]".format(kk))
    for kk,_ in enumerate(H_obj):
        string_list.append("H_obj[{0}]".format(kk))
    for kk,_ in enumerate(C_td_terms):
        string_list.append("C_terms[{0}]".format(kk))
    for kk,_ in enumerate(CA_obj):
        string_list.append("CA_obj[{0}]".format(kk))
    for kk,_ in enumerate(A_td_terms):
        string_list.append("A_terms[{0}]".format(kk))
    #Add nrows to parameters
    string_list.append('nrows')
    for name, value in args.items():
        if isinstance(value, np.ndarray):
            raise TypeError('NumPy arrays not valid args for BR solver.')
        else:
            string_list.append(str(value))
    parameter_string = ",".join(string_list)
    
    if verbose:
        print('BR prep time:', time.time()-_prep_time)
    #
    # generate and compile new cython code if necessary
    #
    if not options.rhs_reuse or config.tdfunc is None:
        if options.rhs_filename is None:
            config.tdname = "rhs" + str(os.getpid()) + str(config.cgen_num)
        else:
            config.tdname = opt.rhs_filename
        if verbose:
            _st = time.time()
        cgen = BR_Codegen(h_terms=len(H_terms), 
                    h_td_terms=H_td_terms, h_obj=H_obj,
                    c_terms=len(C_terms), 
                    c_td_terms=C_td_terms, c_obj=CA_obj,
                    a_terms=len(A_terms), a_td_terms=A_td_terms,
                    spline_count=spline_count,
                    coupled_ops = coupled_ops,
                    coupled_lengths = coupled_lengths,
                    coupled_spectra = coupled_spectra,
                    config=config, sparse=False,
                    use_secular = use_secular,
                    sec_cutoff = sec_cutoff,
                    args=args,
                    use_openmp=options.use_openmp, 
                    omp_thresh=qset.openmp_thresh if qset.has_openmp else None,
                    omp_threads=options.num_cpus, 
                    atol=tol)
        
        cgen.generate(config.tdname + ".pyx")
        code = compile('from ' + config.tdname + ' import cy_td_ode_rhs',
                       '<string>', 'exec')
        exec(code, globals())
        config.tdfunc = cy_td_ode_rhs
        if verbose:
            print('BR compile time:', time.time()-_st)
    initial_vector = mat2vec(rho0.full()).ravel()
    
    _ode = scipy.integrate.ode(config.tdfunc)
    code = compile('_ode.set_f_params(' + parameter_string + ')',
                    '<string>', 'exec')
    _ode.set_integrator('zvode', method=options.method, 
                    order=options.order, atol=options.atol, 
                    rtol=options.rtol, nsteps=options.nsteps,
                    first_step=options.first_step, 
                    min_step=options.min_step,
                    max_step=options.max_step)
    _ode.set_initial_value(initial_vector, tlist[0])
    exec(code, locals())
    
    #
    # prepare output array
    #
    n_tsteps = len(tlist)
    e_sops_data = []

    output = Result()
    output.solver = "brmesolve"
    output.times = tlist

    if options.store_states:
        output.states = []

    if isinstance(e_ops, types.FunctionType):
        n_expt_op = 0
        expt_callback = True

    elif isinstance(e_ops, list):
        n_expt_op = len(e_ops)
        expt_callback = False

        if n_expt_op == 0:
            # fall back on storing states
            output.states = []
            options.store_states = True
        else:
            output.expect = []
            output.num_expect = n_expt_op
            for op in e_ops:
                e_sops_data.append(spre(op).data)
                if op.isherm:
                    output.expect.append(np.zeros(n_tsteps))
                else:
                    output.expect.append(np.zeros(n_tsteps, dtype=complex))

    else:
        raise TypeError("Expectation parameter must be a list or a function")

    #
    # start evolution
    #
    if type(progress_bar)==BaseProgressBar and verbose:
        _run_time = time.time()
    
    progress_bar.start(n_tsteps)

    rho = Qobj(rho0)

    dt = np.diff(tlist)
    for t_idx, t in enumerate(tlist):
        progress_bar.update(t_idx)

        if not _ode.successful():
            raise Exception("ODE integration error: Try to increase "
                            "the allowed number of substeps by increasing "
                            "the nsteps parameter in the Options class.")

        if options.store_states or expt_callback:
            rho.data = dense2D_to_fastcsr_fmode(vec2mat(_ode.y), rho.shape[0], rho.shape[1])

            if options.store_states:
                output.states.append(Qobj(rho, isherm=True))

            if expt_callback:
                # use callback method
                e_ops(t, rho)

        for m in range(n_expt_op):
            if output.expect[m].dtype == complex:
                output.expect[m][t_idx] = expect_rho_vec(e_sops_data[m],
                                                         _ode.y, 0)
            else:
                output.expect[m][t_idx] = expect_rho_vec(e_sops_data[m],
                                                         _ode.y, 1)

        if t_idx < n_tsteps - 1:
            _ode.integrate(_ode.t + dt[t_idx])

    progress_bar.finished()
    
    if type(progress_bar)==BaseProgressBar and verbose:
        print('BR runtime:', time.time()-_run_time)

    if (not options.rhs_reuse) and (config.tdname is not None):
        _cython_build_cleanup(config.tdname)
    
    if options.store_final_state:
        rho.data = dense2D_to_fastcsr_fmode(vec2mat(_ode.y), rho.shape[0], rho.shape[1])
        output.final_state = Qobj(rho, dims=rho0.dims, isherm=True)

    return output
コード例 #58
0
def bloch_redfield_solve(R, ekets, rho0, tlist, e_ops=[], options=None):
    """
    Evolve the ODEs defined by Bloch-Redfield master equation. The
    Bloch-Redfield tensor can be calculated by the function
    :func:`bloch_redfield_tensor`.

    Parameters
    ----------

    R : :class:`qutip.qobj`
        Bloch-Redfield tensor.

    ekets : array of :class:`qutip.qobj`
        Array of kets that make up a basis tranformation for the eigenbasis.

    rho0 : :class:`qutip.qobj`
        Initial density matrix.

    tlist : *list* / *array*
        List of times for :math:`t`.

    e_ops : list of :class:`qutip.qobj` / callback function
        List of operators for which to evaluate expectation values.

    options : :class:`qutip.Qdeoptions`
        Options for the ODE solver.

    Returns
    -------

    output: :class:`qutip.solver`

        An instance of the class :class:`qutip.solver`, which contains either
        an *array* of expectation values for the times specified by `tlist`.

    """

    if options is None:
        options = Options()

    if options.tidy:
        R.tidyup()

    #
    # check initial state
    #
    if isket(rho0):
        # Got a wave function as initial state: convert to density matrix.
        rho0 = rho0 * rho0.dag()

    #
    # prepare output array
    #
    n_tsteps = len(tlist)
    dt = tlist[1] - tlist[0]
    result_list = []

    #
    # transform the initial density matrix and the e_ops opterators to the
    # eigenbasis
    #
    rho_eb = rho0.transform(ekets)
    e_eb_ops = [e.transform(ekets) for e in e_ops]

    for e_eb in e_eb_ops:
        result_list.append(np.zeros(n_tsteps, dtype=complex))

    #
    # setup integrator
    #
    initial_vector = mat2vec(rho_eb.full())
    r = scipy.integrate.ode(cy_ode_rhs)
    r.set_f_params(R.data.data, R.data.indices, R.data.indptr)
    r.set_integrator('zvode',
                     method=options.method,
                     order=options.order,
                     atol=options.atol,
                     rtol=options.rtol,
                     nsteps=options.nsteps,
                     first_step=options.first_step,
                     min_step=options.min_step,
                     max_step=options.max_step)
    r.set_initial_value(initial_vector, tlist[0])

    #
    # start evolution
    #
    dt = np.diff(tlist)
    for t_idx, _ in enumerate(tlist):

        if not r.successful():
            break

        rho_eb.data = vec2mat(r.y)

        # calculate all the expectation values, or output rho_eb if no
        # expectation value operators are given
        if e_ops:
            rho_eb_tmp = Qobj(rho_eb)
            for m, e in enumerate(e_eb_ops):
                result_list[m][t_idx] = expect(e, rho_eb_tmp)
        else:
            result_list.append(rho_eb.transform(ekets, True))

        if t_idx < n_tsteps - 1:
            r.integrate(r.t + dt[t_idx])

    return result_list
コード例 #59
0
ファイル: floquet.py プロジェクト: christian512/qutip
def floquet_markov_mesolve(
    R,
    rho0,
    tlist,
    e_ops,
    options=None,
    floquet_basis=True,
    f_modes_0=None,
    f_modes_table_t=None,
    f_energies=None,
    T=None,
):
    """
    Solve the dynamics for the system using the Floquet-Markov master equation.

    .. note::

        It is important to understand in which frame and basis the results
        are returned here.

    Parameters
    ----------

    R : array
        The Floquet-Markov master equation tensor `R`.

    rho0 : :class:`qutip.qobj`
        Initial density matrix.  If ``f_modes_0`` is not passed, this density
        matrix is assumed to be in the Floquet picture.

    tlist : *list* / *array*
        list of times for :math:`t`.

    e_ops : list of :class:`qutip.qobj` / callback function
        list of operators for which to evaluate expectation values.

    options : :class:`qutip.solver.Options`
        options for the ODE solver.

    floquet_basis: bool, True
        If ``True``, states and expectation values will be returned in the
        Floquet basis.  If ``False``, a transformation will be made to the
        computational basis; this will be in the lab frame if
        ``f_modes_table``, ``T` and ``f_energies`` are all supplied, or the
        interaction picture (defined purely be f_modes_0) if they are not.

    f_modes_0 : list of :class:`qutip.qobj` (kets), optional
        A list of initial Floquet modes, used to transform the given starting
        density matrix into the Floquet basis.  If this is not passed, it is
        assumed that ``rho`` is already in the Floquet basis.

    f_modes_table_t : nested list of :class:`qutip.qobj` (kets), optional
        A lookup-table of Floquet modes at times precalculated by
        :func:`qutip.floquet.floquet_modes_table`.  Necessary if
        ``floquet_basis`` is ``False`` and the transformation should be made
        back to the lab frame.

    f_energies : array_like of float, optional
        The precalculated Floquet quasienergies.  Necessary if
        ``floquet_basis`` is ``False`` and the transformation should be made
        back to the lab frame.

    T : float, optional
        The time period of driving.  Necessary if ``floquet_basis`` is
        ``False`` and the transformation should be made back to the lab frame.

    Returns
    -------

    output : :class:`qutip.solver.Result`
        An instance of the class :class:`qutip.solver.Result`, which
        contains either an *array* of expectation values or an array of
        state vectors, for the times specified by `tlist`.
    """
    opt = options or Options()
    if opt.tidy:
        R.tidyup()
    rho0 = rho0.proj() if rho0.isket else rho0

    # Prepare output object.
    dt = tlist[1] - tlist[0]
    output = Result()
    output.solver = "fmmesolve"
    output.times = tlist
    if isinstance(e_ops, FunctionType):
        expt_callback = True
        store_states = opt.store_states or False
    else:
        expt_callback = False
        try:
            e_ops = list(e_ops)
        except TypeError:
            raise TypeError("`e_ops` must be iterable or a function") from None
        n_expt_op = len(e_ops)
        if n_expt_op == 0:
            store_states = True
        else:
            output.expect = []
            output.num_expect = n_expt_op
            for op in e_ops:
                dtype = np.float64 if op.isherm else np.complex128
                output.expect.append(np.zeros(len(tlist), dtype=dtype))
        store_states = opt.store_states or (n_expt_op == 0)
    if store_states:
        output.states = []

    # Choose which frame transformations should be done on the initial and
    # evolved states.
    lab_lookup = [f_modes_table_t, f_energies, T]
    if (any(x is None for x in lab_lookup)
            and not all(x is None for x in lab_lookup)):
        warnings.warn(
            "if transformation back to the computational basis in the lab"
            "frame is desired, all of `f_modes_t`, `f_energies` and `T` must"
            "be supplied.")
        f_modes_table_t = f_energies = T = None

    # Initial state.
    if f_modes_0 is not None:
        rho0 = rho0.transform(f_modes_0)

    # Evolved states.
    if floquet_basis:

        def transform(rho, t):
            return rho
    elif f_modes_table_t is not None:
        # Lab frame, computational basis.
        def transform(rho, t):
            f_modes_t = floquet_modes_t_lookup(f_modes_table_t, t, T)
            f_states_t = floquet_states(f_modes_t, f_energies, t)
            return rho.transform(f_states_t, True)
    elif f_modes_0 is not None:
        # Interaction picture, computational basis.
        def transform(rho, t):
            return rho.transform(f_modes_0, False)
    else:
        raise ValueError(
            "cannot transform out of the Floquet basis without some knowledge "
            "of the Floquet modes.  Pass `f_modes_0`, or all of `f_modes_t`, "
            "`f_energies` and `T`.")

    # Setup integrator.
    initial_vector = mat2vec(rho0.full())
    r = scipy.integrate.ode(cy_ode_rhs)
    r.set_f_params(R.data.data, R.data.indices, R.data.indptr)
    r.set_integrator('zvode',
                     method=opt.method,
                     order=opt.order,
                     atol=opt.atol,
                     rtol=opt.rtol,
                     max_step=opt.max_step)
    r.set_initial_value(initial_vector, tlist[0])

    # Main evolution loop.
    for t_idx, t in enumerate(tlist):
        if not r.successful():
            break
        rho = transform(Qobj(vec2mat(r.y), rho0.dims, rho0.shape), t)
        if expt_callback:
            e_ops(t, rho)
        else:
            for m, e_op in enumerate(e_ops):
                output.expect[m][t_idx] = expect(e_op, rho)
        if store_states:
            output.states.append(rho)
        r.integrate(r.t + dt)
    return output