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))]
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)
def bloch_redfield_solve(R, ekets, rho0, tlist, e_ops=[], options=None, progress_bar=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() if progress_bar is None: progress_bar = BaseProgressBar() elif progress_bar is True: progress_bar = TextProgressBar() # # 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: if e_eb.isherm: result_list.append(np.zeros(n_tsteps, dtype=float)) else: 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) progress_bar.start(n_tsteps) for t_idx, _ in enumerate(tlist): progress_bar.update(t_idx) if not r.successful(): break rho_eb.data = dense2D_to_fastcsr_fmode(vec2mat(r.y), rho0.shape[0], rho0.shape[1]) # 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]) progress_bar.finished() return result_list
def bloch_redfield_solve(R, ekets, rho0, tlist, e_ops=[], options=None, progress_bar=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() if progress_bar is None: progress_bar = BaseProgressBar() elif progress_bar is True: progress_bar = TextProgressBar() # # 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: if e_eb.isherm: result_list.append(np.zeros(n_tsteps, dtype=float)) else: 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) progress_bar.start(n_tsteps) for t_idx, _ in enumerate(tlist): progress_bar.update(t_idx) if not r.successful(): break rho_eb.data = dense2D_to_fastcsr_fmode(vec2mat(r.y), rho0.shape[0], rho0.shape[1]) # 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]) progress_bar.finished() return result_list
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)
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)
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, _safe_mode=False) 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, _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) 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: return Qobj(u[:, :, 1], dims=dims) else: return np.array( [Qobj(u[:, :, k], dims=dims) for k in range(len(tlist))], dtype=object)
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))]