TensoredMeasFitter
class TensoredMeasFitter(results, mit_pattern, substate_labels_list=None, circlabel='')
Bases: object
Measurement correction fitter for a tensored calibration.
Initialize a measurement calibration matrix from the results of running the circuits returned by measurement_calibration_circuits.
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.
Parameters
- results – the results of running the measurement calibration circuits. If this is None, the user will set calibration matrices later.
- mit_pattern (
List[List[int]]) – qubits to perform the measurement correction on, divided to groups according to tensors - substate_labels_list (
Optional[List[List[str]]]) – for each calibration matrix, the labels of its rows and columns. If None, the labels are ordered lexicographically - circlabel (
str) – if the qubits were labeled
Raises
ValueError – if the mit_pattern doesn’t match the substate_labels_list
Methods
add_data
TensoredMeasFitter.add_data(new_results, rebuild_cal_matrix=True)
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
TensoredMeasFitter.readout_fidelity(cal_index=0, label_list=None)
Based on the results, output the readout fidelity, which is the average of the diagonal entries in the calibration matrices.
Parameters
- cal_index (integer) – readout fidelity for this index in _cal_matrices
- label_list (list) – Returns the average fidelity over of the groups f states. In the form of a list of lists of states. If None, then each state used in the construction of the calibration matrices forms a group of size 1
Returns
The readout fidelity (assignment fidelity)
Return type
numpy.array
Raises
QiskitError – If the calibration matrix has not been set for the object.
Additional Information:
The on-diagonal elements of the calibration matrices are the probabilities of measuring state ‘x’ given preparation of state ‘x’.
subset_fitter
TensoredMeasFitter.subset_fitter(qubit_sublist)
Return a fitter object that is a subset of the qubits in the original list.
This is only a partial implementation of the subset_fitter method since only mitigation patterns of length 1 are supported. This corresponds to patterns of the form [[0], [1], [2], ...]. Note however, that such patterns are a good first approximation to mitigate readout errors on large quantum circuits.
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
Raises
- QiskitError – If the calibration matrix is not initialized
- QiskitError – If the mit pattern is not a tensor of single-qubit measurement error mitigation.
- QiskitError – If a qubit in the given
qubit_sublistis not in the list of qubits in the mit. pattern.
Attributes
cal_matrices
Return cal_matrices.
filter
Return a measurement filter using the cal matrices.
nqubits
Return _qubit_list_sizes.
substate_labels_list
Return _substate_labels_list.