qom.utils.solvers module

Module containing utility functions for solvers.

qom.utils.solvers.get_func_Lyapunov_exponents(SystemClass, params: dict = {}, steady_state: bool = True, cb_update=None)

Function to get the function to obtain the Lyapunov exponents.

Parameters:

  • SystemClass (qom.systems.*) – Uninitialized system class. Requires predefined system methods for certain solver methods.

  • params (dict, optional) – Parameters for the solver. Refer to qom.solvers.deterministic.HLESolver, qom.solvers.deterministic.SSHLESolver and qom.solvers.measure.get_Lyapunov_exponents for available parameters.

  • steady_state (bool, default=True.) – Whether the calculated modes and correlations are steady state values or time series.

  • cb_update (callable, optional) – Callback function to update status and progress, formatted as cb_update(status, progress, reset), where status is a string, progress is a float and reset is a boolean.

Returns:

get_le – Function to obtain the Lyapunov exponents. Returns a numpy.ndarray with shape (2 * num_modes, ).

Return type:

callable

qom.utils.solvers.get_func_quantum_correlation_measures(SystemClass, params: dict = {}, steady_state: bool = True, cb_update=None)

Function to get the function to obtain the quantum correlation measures.

Parameters:

  • SystemClass (qom.systems.*) – Uninitialized system class. Requires predefined system methods for certain solver methods.

  • params (dict, optional) – Parameters for the solver. Refer to qom.solvers.deterministic.HLESolver, qom.solvers.deterministic.SSHLESolver and qom.solvers.measure.QCMSolver for available parameters.

  • steady_state (bool, default=True.) – Whether the calculated modes and correlations are steady state values or time series.

  • cb_update (callable, optional) – Callback function to update status and progress, formatted as cb_update(status, progress, reset), where status is a string, progress is a float and reset is a boolean.

Returns:

get_qcm – Function to obtain the quantum correlation measures. Returns a numpy.ndarray with shape (dim, num_measure_codes).

Return type:

callable

qom.utils.solvers.get_func_stability_zone(SystemClass, params: dict = {}, steady_state: bool = True, use_rhc: bool = False, cb_update=None)

Function to get the function to obtain the stability zone.

Parameters:

  • SystemClass (qom.systems.*) – Uninitialized system class. Requires predefined system methods for certain solver methods.

  • params (dict, optional) – Parameters for the solver. Refer to qom.solvers.deterministic.HLESolver, qom.solvers.deterministic.SSHLESolver and qom.solvers.stability.RHCSolver for available parameters. If the value of key "system_measure_name" is "coeffs_A", the stability is calculated using the coefficients, else the drift matrices are used (fallback).

  • steady_state (bool, default=True.) – Whether the calculated modes and correlations are steady state values or time series.

  • use_rhc (bool, default=False) – Option to use the Routh-Hurwitz criteria to calculate the counts for the unstable eigenvalues.

  • cb_update (callable, optional) – Callback function to update status and progress, formatted as cb_update(status, progress, reset), where status is a string, progress is a float and reset is a boolean.

Returns:

get_sz – Function to obtain the stability zone. Returns a numpy.ndarray with shape (dim, ). If steady_state is set to True, the array contains a single element denoting the multi-stability indicator. Refer to qom.solvers.measure.get_stability_zone function for the meaning of indicators.

Return type:

callable

qom.utils.solvers.get_func_system_measures(SystemClass, params: dict = {}, steady_state: bool = True, cb_update=None)

Function to get the function to obtain the system measures.

Parameters:

  • SystemClass (qom.systems.*) – Uninitialized system class. Requires predefined system methods for certain solver methods.

  • params (dict, optional) – Parameters for the solver. Refer to qom.solvers.deterministic.HLESolver and qom.solvers.deterministic.SSHLESolver and qom.solvers.measure.get_system_measures for available parameters.

  • steady_state (bool, default=True.) – Whether the calculated modes and correlations are steady state values or time series.

  • cb_update (callable, optional) – Callback function to update status and progress, formatted as cb_update(status, progress, reset), where status is a string, progress is a float and reset is a boolean.

Returns:

get_sm – Function to obtain the system measures. Returns a numpy.ndarray with shape (dim, ) plus the shape of each measure.

Return type:

callable

qom.utils.solvers.plot_mcqt_solver_results(solver, params_plotter: dict)

Helper function to plot results.

Parameters:
qom.utils.solvers.run_mcqt_solver_instance(args)

Function to run a single instance of wrap_mcqt_solver.

Parameters:

args (list) – Arguments of the wrap_mcqt_solver function.

Returns:

solver – Instance of the solver.

Return type:

qom.solvers.stochastic.MCQTSolver

qom.utils.solvers.run_mcqt_solvers_in_parallel(system, params: dict, num_trajs: int = 1000, plot: bool = False, subplots: bool = False, params_plotter: dict = {}, max_processes: int = None, cb_update=None)

Function to run multiple MCQTSolver in parallel processes.

Parameters:

  • system (qom.systems.base) – Instance of the system. Requires predefined system methods get_ops_collapse, get_ops_expect, get_H_0 and get_ivc. For time-dependent Hamiltonians, the method get_H_t should also be defined. Refer to Notes of qom.solvers.stochastic.MCQTSolver for their implementations.

  • params (dict) – Parameters of the solver. Refer to Notes of qom.solvers.stochastic.MCQTSolver for all available options.

  • num_trajs (int, default=1000) – Number of trajectories.

  • plot (bool, default=False) – Option to plot the results of the main process.

  • subplots (bool, default=False) – Option to plot the results of each subprocesses.

  • params_plotter (dict, optional) – Parameters of the plotter.

  • max_processes (int, optional) – Maximum number of solvers to run in parallel. The number of slices is decided by the dimensionality of the Hilbert space and the number of trajectories. For smaller number of trajectories, a single process is run without parallelization. Default value of dimension is \(5 \times 10^{4} / N\), where \(N\) is the dimension of the combined Hilbert space.

  • cb_update (callable) – Callback function to update status and progress, formatted as cb_update(status, progress, reset), where status is a string, progress is a float and reset is a boolean.

Returns:

solver – Instance of the solver.

Return type:

qom.solvers.stochastic.MCQTSolver

qom.utils.solvers.wrap_mcqt_solver(system, params: dict, num_trajs: int = 1000, plot: bool = False, params_plotter: dict = {}, cb_update=None, parallel=False, p_index: int = 0, p_start: float = None)

Function to wrap MCQTSolver.

Parameters:

  • system (qom.systems.base) – Instance of the system. Requires predefined system methods get_ops_collapse, get_ops_expect, get_H_0 and get_ivc. For time-dependent Hamiltonians, the method get_H_t should also be defined. Refer to Notes of qom.solvers.stochastic.MCQTSolver for their implementations.

  • params (dict) – Parameters of the solver. Refer to Notes of qom.solvers.stochastic.MCQTSolver for all available options.

  • num_trajs (int, default=1000) – Number of trajectories.

  • plot (bool, default=False) – Option to plot the results of the main process.

  • params_plotter (dict, optional) – Parameters of the plotter.

  • cb_update (callable) – Callback function to update status and progress, formatted as cb_update(status, progress, reset), where status is a string, progress is a float and reset is a boolean.

  • parallel (bool, default=False) – Option to format outputs when running in parallel.

  • p_index (int, default=0) – Index of the process.

  • p_start (float, optional) – Time at which the process was started. If not provided, the value is initialized to current time.

Returns:

solver – Instance of the solver.

Return type:

qom.solvers.stochastic.MCQTSolver