qiskit.algorithms.PhaseEstimationResult
class PhaseEstimationResult(num_evaluation_qubits, circuit_result, phases)
Store and manipulate results from running PhaseEstimation.
This class is instantiated by the PhaseEstimation class, not via user code. The PhaseEstimation class generates a list of phases and corresponding weights. Upon completion it returns the results as an instance of this class. The main method for accessing the results is filter_phases.
Parameters
- num_evaluation_qubits (
int) – number of qubits in phase-readout register. - circuit_result (
Result) – result object returned by method running circuit. - phases (
Union[ndarray,Dict[str,float]]) – ndarray or dict of phases and frequencies determined by QPE.
__init__
__init__(num_evaluation_qubits, circuit_result, phases)
Parameters
- num_evaluation_qubits (
int) – number of qubits in phase-readout register. - circuit_result (
Result) – result object returned by method running circuit. - phases (
Union[ndarray,Dict[str,float]]) – ndarray or dict of phases and frequencies determined by QPE.
Methods
__init__(num_evaluation_qubits, …) | type num_evaluation_qubitsint |
combine(result) | Any property from the argument that exists in the receiver is updated. |
filter_phases([cutoff, as_float]) | Return a filtered dict of phases (keys) and frequencies (values). |
Attributes
circuit_result | Return the result object returned by running the QPE circuit (on hardware or simulator). |
most_likely_phase | Return the estimated phase as a number in . |
phases | Return all phases and their frequencies computed by QPE. |
circuit_result
Return the result object returned by running the QPE circuit (on hardware or simulator).
This is useful for inspecting and troubleshooting the QPE algorithm.
Return type
Result
combine
combine(result)
Any property from the argument that exists in the receiver is updated. :type result: AlgorithmResult :param result: Argument result with properties to be set.
Raises
TypeError – Argument is None
Return type
None
filter_phases
filter_phases(cutoff=0.0, as_float=True)
Return a filtered dict of phases (keys) and frequencies (values).
Only phases with frequencies (counts) larger than cutoff are included. It is assumed that the run method has been called so that the phases have been computed. When using a noiseless, shot-based simulator to read a single phase that can be represented exactly by num_evaluation_qubits, all the weight will be concentrated on a single phase. In all other cases, many, or all, bit strings will have non-zero weight. This method is useful for filtering out these uninteresting bit strings.
Parameters
- cutoff (
float) – Minimum weight of number of counts required to keep a bit string. The default value is 0.0. - as_float (
bool) – If True, returned keys are floats in . If False returned keys are bit strings.
Return type
Dict
Returns
A filtered dict of phases (keys) and frequencies (values).
most_likely_phase
Return the estimated phase as a number in .
1.0 corresponds to a phase of . It is assumed that the input vector is an eigenvector of the unitary so that the peak of the probability density occurs at the bit string that most closely approximates the true phase.
Return type
float
phases
Return all phases and their frequencies computed by QPE.
This is an array or dict whose values correspond to weights on bit strings.
Return type
Union[ndarray, dict]