QuantumInstance
class QuantumInstance(backend, shots=1024, seed_simulator=None, max_credits=10, basis_gates=None, coupling_map=None, initial_layout=None, pass_manager=None, seed_transpiler=None, optimization_level=None, backend_options=None, noise_model=None, timeout=None, wait=5.0, skip_qobj_validation=True, measurement_error_mitigation_cls=None, cals_matrix_refresh_period=30, measurement_error_mitigation_shots=None, job_callback=None)
Bases: object
Quantum Backend including execution setting.
Quantum Instance holds a Qiskit Terra backend as well as configuration for circuit transpilation and execution. When provided to an Aqua algorithm the algorithm will execute the circuits it needs to run using the instance.
Parameters
- backend (
Union
[Backend
,BaseBackend
]) – Instance of selected backend - shots (
int
) – Number of repetitions of each circuit, for sampling - seed_simulator (
Optional
[int
]) – Random seed for simulators - max_credits (
int
) – Maximum credits to use - basis_gates (
Optional
[List
[str
]]) – List of basis gate names supported by the target. Defaults to basis gates of the backend. - coupling_map (
Union
[CouplingMap
,List
[List
],None
]) – Coupling map (perhaps custom) to target in mapping - initial_layout (
Union
[Layout
,Dict
,List
,None
]) – Initial layout of qubits in mapping - pass_manager (
Optional
[PassManager
]) – Pass manager to handle how to compile the circuits - seed_transpiler (
Optional
[int
]) – The random seed for circuit mapper - optimization_level (
Optional
[int
]) – How much optimization to perform on the circuits. Higher levels generate more optimized circuits, at the expense of longer transpilation time. - backend_options (
Optional
[Dict
]) – All running options for backend, please refer to the provider of the backend for information as to what options it supports. - noise_model (
Optional
[NoiseModel
]) – noise model for simulator - timeout (
Optional
[float
]) – Seconds to wait for job. If None, wait indefinitely. - wait (
float
) – Seconds between queries for job result - skip_qobj_validation (
bool
) – Bypass Qobj validation to decrease circuit processing time during submission to backend. - measurement_error_mitigation_cls (
Optional
[Callable
]) – The approach to mitigate measurement errors. Qiskit Ignis provides fitter classes for this functionality and CompleteMeasFitter from qiskit.ignis.mitigation.measurement module can be used here. (TensoredMeasFitter is not supported). - cals_matrix_refresh_period (
int
) – How often to refresh the calibration matrix in measurement mitigation. in minutes - measurement_error_mitigation_shots (
Optional
[int
]) – The number of shots number for building calibration matrix. If None, the main shots parameter value is used. - job_callback (
Optional
[Callable
]) – Optional user supplied callback which can be used to monitor job progress as jobs are submitted for processing by an Aqua algorithm. The callback is provided the following arguments: job_id, job_status, queue_position, job
Raises
- AquaError – the shots exceeds the maximum number of shots
- AquaError – set noise model but the backend does not support that
- AquaError – set backend_options but the backend does not support that
Methods
assemble
cals_matrix
QuantumInstance.cals_matrix(qubit_index=None)
Get the stored calibration matrices and its timestamp.
Parameters
qubit_index (Optional
[List
[int
]]) – the qubit index of corresponding calibration matrix. If None, return all stored calibration matrices.
Return type
Union
[Tuple
[ndarray
, float
], Dict
[str
, Tuple
[ndarray
, float
]], None
]
Returns
The calibration matrix and the creation timestamp if qubit_index is not None otherwise, return all matrices and their timestamp in a dictionary.
execute
QuantumInstance.execute(circuits, had_transpiled=False)
A wrapper to interface with quantum backend.
Parameters
- circuits (
Union
[QuantumCircuit
,List
[QuantumCircuit
]]) – circuits to execute - had_transpiled (
bool
) – whether or not circuits had been transpiled
Return type
Result
Returns
Result object
TODO: Maybe we can combine the circuits for the main ones and calibration circuits before
assembling to the qobj.
maybe_refresh_cals_matrix
QuantumInstance.maybe_refresh_cals_matrix(timestamp=None)
Calculate the time difference from the query of last time.
Parameters
timestamp (Optional
[float
]) – timestamp
Return type
bool
Returns
Whether or not refresh the cals_matrix
reset_execution_results
QuantumInstance.reset_execution_results()
Reset execution results
Return type
None
set_config
QuantumInstance.set_config(**kwargs)
Set configurations for the quantum instance.
transpile
QuantumInstance.transpile(circuits)
A wrapper to transpile circuits to allow algorithm access the transpiled circuits. :type circuits: Union
[QuantumCircuit
, List
[QuantumCircuit
]] :param circuits: circuits to transpile
Return type
List
[QuantumCircuit
]
Returns
The transpiled circuits, it is always a list even though the length is one.
Attributes
backend
Return BaseBackend backend object.
backend_config
Getter of backend_config.
backend_name
Return backend name.
backend_options
Getter of backend_options.
cals_matrix_refresh_period
returns matrix refresh period
circuit_summary
Getter of circuit summary.
compile_config
Getter of compile_config.
is_local
Return True if backend is a local backend.
is_simulator
Return True if backend is a simulator.
is_statevector
Return True if backend is a statevector-type simulator.
measurement_error_mitigation_cls
returns measurement error mitigation cls
measurement_error_mitigation_shots
returns measurement error mitigation shots
noise_config
Getter of noise_config.
qjob_config
Getter of qjob_config.
run_config
Getter of run_config.
skip_qobj_validation
checks if skip qobj validation
time_taken
Accumulated time taken for execution.
Return type
float