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QuantumInstance

class QuantumInstance(backend, shots=None, seed_simulator=None, max_credits=None, basis_gates=None, coupling_map=None, initial_layout=None, pass_manager=None, bound_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, mit_pattern=None, max_job_retries=50)[source]

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 (Backend) – Instance of selected backend

  • shots (Optional[int]) – Number of repetitions of each circuit, for sampling. If None, the shots are extracted from the backend. If the backend has none set, the default is 1024.

  • seed_simulator (Optional[int]) – Random seed for simulators

  • max_credits (Optional[int]) – DEPRECATED This parameter is deprecated as of Qiskit Terra 0.20.0, and will be removed in a future release. This parameter has no effect on modern IBM Quantum systems, and no alternative is necessary.

  • basis_gates (Optional[List[str]]) – List of basis gate names supported by the target. Defaults to basis gates of the backend.

  • coupling_map (Optional[Union['CouplingMap', List[List]]]) – Coupling map (perhaps custom) to target in mapping

  • initial_layout (Optional[Union['Layout', Dict, List]]) – Initial layout of qubits in mapping

  • pass_manager (Optional['PassManager']) – Pass manager to handle how to compile the circuits. To run only this pass manager and not the bound_pass_manager, call the transpile() method with the argument pass_manager=quantum_instance.unbound_pass_manager.

  • bound_pass_manager (Optional['PassManager']) – A second pass manager to apply on bound circuits only, that is, circuits without any free parameters. To only run this pass manager and not pass_manager call the transpile() method with the argument pass_manager=quantum_instance.bound_pass_manager. manager should also be run.

  • 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. The classes CompleteMeasFitter or TensoredMeasFitter from the qiskit.utils.mitigation module can be used here as exact values, not instances. TensoredMeasFitter doesn’t support the subset_fitter method.

  • 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

  • mit_pattern (Optional[List[List[int]]]) – Qubits on which to perform the TensoredMeasFitter measurement correction, divided to groups according to tensors. If None and qr is given then assumed to be performed over the entire qr as one group (default None).

  • max_job_retries (int) – positive non-zero number of trials for the job set (-1 for infinite trials) (default: 50)

Raises
  • QiskitError – the shots exceeds the maximum number of shots

  • QiskitError – set noise model but the backend does not support that

  • QiskitError – set backend_options but the backend does not support that

Methods

assemble

assemble circuits

cals_matrix

Get the stored calibration matrices and its timestamp.

execute

A wrapper to interface with quantum backend.

maybe_refresh_cals_matrix

Calculate the time difference from the query of last time.

reset_execution_results

Reset execution results

set_config

Set configurations for the quantum instance.

transpile

A wrapper to transpile circuits to allow algorithm access the transpiled circuits.

Attributes

backend

Return Backend backend object.

backend_config

Getter of backend_config.

backend_name

Return backend name.

backend_options

Getter of backend_options.

bound_pass_manager

Return the pass manager for designated for bound circuits.

Returns

The pass manager for bound circuits, if it has been set.

Return type

Optional[‘PassManager’]

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.

max_job_retries

Getter of max tries

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

unbound_pass_manager

Return the pass manager for designated for unbound circuits.

Returns

The pass manager for unbound circuits, if it has been set.

Return type

Optional[‘PassManager’]