CompleteMeasFitter

class qiskit.utils.mitigation.CompleteMeasFitter(results, state_labels, qubit_list=None, circlabel='')[source]

Bases: object

Deprecated: Measurement correction fitter for a full calibration

Initialize a measurement calibration matrix from the results of running the circuits returned by measurement_calibration_circuits

A wrapper for the tensored fitter

Warning

This class is not a public API. The internals are not stable and will likely change. It is used solely for the measurement_error_mitigation_cls kwarg of the QuantumInstance class’s constructor (as a class not an instance). Anything outside of that usage does not have the normal user-facing API stability.

Deprecated since version 0.24.0: The class qiskit.utils.mitigation.fitters.CompleteMeasFitter is deprecated as of qiskit-terra 0.24.0. It will be removed no earlier than 3 months after the release date. For code migration guidelines, visit https://qisk.it/qi_migration.

Parameters:

  • results – the results of running the measurement calibration circuits. If this is None the user will set a calibration matrix later.

  • state_labels (List[str]) – list of calibration state labels returned from measurement_calibration_circuits. The output matrix will obey this ordering.

  • qubit_list (List[int]) – List of the qubits (for reference and if the subset is needed). If None, the qubit_list will be created according to the length of state_labels[0].

  • circlabel (str) – if the qubits were labeled.

Attributes

cal_matrix

Return cal_matrix.

filter

Return a measurement filter using the cal matrix.

qubit_list

Return list of qubits.

state_labels

Return state_labels.

Methods

add_data(new_results, rebuild_cal_matrix=True)[source]

Add measurement calibration data

Parameters:

  • new_results (list or qiskit.result.Result) – a single result or list of result objects.

  • rebuild_cal_matrix (bool) – rebuild the calibration matrix

readout_fidelity(label_list=None)[source]

Based on the results, output the readout fidelity which is the normalized trace of the calibration matrix

Parameters:

label_list (bool) – If None, returns the average assignment fidelity of a single state. Otherwise it returns the assignment fidelity to be in any one of these states averaged over the second index.

Returns:

readout fidelity (assignment fidelity)

Return type:

numpy.array

Additional Information:

The on-diagonal elements of the calibration matrix are the probabilities of measuring state ‘x’ given preparation of state ‘x’ and so the normalized trace is the average assignment fidelity

subset_fitter(qubit_sublist)[source]

Return a fitter object that is a subset of the qubits in the original list.

Parameters:

qubit_sublist (list) – must be a subset of qubit_list

Returns:

A new fitter that has the calibration for a

subset of qubits

Return type:

CompleteMeasFitter

Raises:

QiskitError – If the calibration matrix is not initialized