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)
def odesolve(H, rho0, tlist, c_op_list, e_ops, args=None, options=None):
"""
Master equation evolution of a density matrix for a given Hamiltonian.
Evolution of a state vector or density matrix (`rho0`) for a given
Hamiltonian (`H`) and set of collapse operators (`c_op_list`), by
integrating the set of ordinary differential equations that define the
system. The output is either the state vector at arbitrary points in time
(`tlist`), or the expectation values of the supplied operators
(`e_ops`).
For problems with time-dependent Hamiltonians, `H` can be a callback
function that takes two arguments, time and `args`, and returns the
Hamiltonian at that point in time. `args` is a list of parameters that is
passed to the callback function `H` (only used for time-dependent
Hamiltonians).
Parameters
----------
H : :class:`qutip.qobj`
system Hamiltonian, or a callback function for time-dependent
Hamiltonians.
rho0 : :class:`qutip.qobj`
initial density matrix or state vector (ket).
tlist : *list* / *array*
list of times for :math:`t`.
c_op_list : list of :class:`qutip.qobj`
list of collapse operators.
e_ops : list of :class:`qutip.qobj` / callback function
list of operators for which to evaluate expectation values.
args : *dictionary*
dictionary of parameters for time-dependent Hamiltonians and
collapse operators.
options : :class:`qutip.Options`
with options for the ODE solver.
Returns
-------
output :array
Expectation values of wavefunctions/density matrices
for the times specified by `tlist`.
Notes
-----
On using callback function: odesolve transforms all :class:`qutip.qobj`
objects to sparse matrices before handing the problem to the integrator
function. In order for your callback function to work correctly, pass
all :class:`qutip.qobj` objects that are used in constructing the
Hamiltonian via args. odesolve will check for :class:`qutip.qobj` in
`args` and handle the conversion to sparse matrices. All other
:class:`qutip.qobj` objects that are not passed via `args` will be
passed on to the integrator to scipy who will raise an NotImplemented
exception.
Deprecated in QuTiP 2.0.0. Use :func:`mesolve` instead.
"""
warnings.warn("odesolve is deprecated since 2.0.0. Use mesolve instead.", DeprecationWarning)
if debug:
print(inspect.stack()[0][3])
if options is None:
options = Options()
if (c_op_list and len(c_op_list) > 0) or not isket(rho0):
if isinstance(H, list):
output = _mesolve_list_td(H, rho0, tlist, c_op_list, e_ops, args, options, BaseProgressBar())
if isinstance(H, (types.FunctionType, types.BuiltinFunctionType, partial)):
output = _mesolve_func_td(H, rho0, tlist, c_op_list, e_ops, args, options, BaseProgressBar())
else:
output = _mesolve_const(H, rho0, tlist, c_op_list, e_ops, args, options, BaseProgressBar())
else:
if isinstance(H, list):
output = _sesolve_list_td(H, rho0, tlist, e_ops, args, options, BaseProgressBar())
if isinstance(H, (types.FunctionType, types.BuiltinFunctionType, partial)):
output = _sesolve_func_td(H, rho0, tlist, e_ops, args, options, BaseProgressBar())
else:
output = _sesolve_const(H, rho0, tlist, e_ops, args, options, BaseProgressBar())
if len(e_ops) > 0:
return output.expect
else:
return output.states
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)
def odesolve(H, rho0, tlist, c_op_list, e_ops, args=None, options=None):
"""
Master equation evolution of a density matrix for a given Hamiltonian.
Evolution of a state vector or density matrix (`rho0`) for a given
Hamiltonian (`H`) and set of collapse operators (`c_op_list`), by
integrating the set of ordinary differential equations that define the
system. The output is either the state vector at arbitrary points in time
(`tlist`), or the expectation values of the supplied operators
(`e_ops`).
For problems with time-dependent Hamiltonians, `H` can be a callback
function that takes two arguments, time and `args`, and returns the
Hamiltonian at that point in time. `args` is a list of parameters that is
passed to the callback function `H` (only used for time-dependent
Hamiltonians).
Parameters
----------
H : :class:`qutip.qobj`
system Hamiltonian, or a callback function for time-dependent
Hamiltonians.
rho0 : :class:`qutip.qobj`
initial density matrix or state vector (ket).
tlist : *list* / *array*
list of times for :math:`t`.
c_op_list : list of :class:`qutip.qobj`
list of collapse operators.
e_ops : list of :class:`qutip.qobj` / callback function
list of operators for which to evaluate expectation values.
args : *dictionary*
dictionary of parameters for time-dependent Hamiltonians and
collapse operators.
options : :class:`qutip.Odeoptions`
with options for the ODE solver.
Returns
-------
output :array
Expectation values of wavefunctions/density matrices
for the times specified by `tlist`.
Notes
-----
On using callback function: odesolve transforms all :class:`qutip.qobj`
objects to sparse matrices before handing the problem to the integrator
function. In order for your callback function to work correctly, pass
all :class:`qutip.qobj` objects that are used in constructing the
Hamiltonian via args. odesolve will check for :class:`qutip.qobj` in
`args` and handle the conversion to sparse matrices. All other
:class:`qutip.qobj` objects that are not passed via `args` will be
passed on to the integrator to scipy who will raise an NotImplemented
exception.
Deprecated in QuTiP 2.0.0. Use :func:`mesolve` instead.
"""
warnings.warn("odesolve is deprecated since 2.0.0. Use mesolve instead.",
DeprecationWarning)
if debug:
print(inspect.stack()[0][3])
if options is None:
options = Odeoptions()
if (c_op_list and len(c_op_list) > 0) or not isket(rho0):
if isinstance(H, list):
output = _mesolve_list_td(H, rho0, tlist, c_op_list, e_ops, args,
options, BaseProgressBar())
if isinstance(
H, (types.FunctionType, types.BuiltinFunctionType, partial)):
output = _mesolve_func_td(H, rho0, tlist, c_op_list, e_ops, args,
options, BaseProgressBar())
else:
output = _mesolve_const(H, rho0, tlist, c_op_list, e_ops, args,
options, BaseProgressBar())
else:
if isinstance(H, list):
output = _sesolve_list_td(H, rho0, tlist, e_ops, args, options,
BaseProgressBar())
if isinstance(
H, (types.FunctionType, types.BuiltinFunctionType, partial)):
output = _sesolve_func_td(H, rho0, tlist, e_ops, args, options,
BaseProgressBar())
else:
output = _sesolve_const(H, rho0, tlist, e_ops, args, options,
BaseProgressBar())
if len(e_ops) > 0:
return output.expect
else:
return output.states
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:
for name, value in args.items():
if isinstance(value, np.ndarray):
globals()['var_%s'%name] = value
string += 'var_%s,'%name
else:
string += str(value) + ','
# 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 cy_td_ode_rhs',
'<string>', 'exec')
exec(code, globals())
odeconfig.tdfunc = cy_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)