qiskit.utils.QuantumInstance¶

class QuantumInstance(backend, shots=None, 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)[source]¶

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 (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 (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 (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
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

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

__init__(backend, shots=None, 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)[source]¶

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 (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 (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 (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
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

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

`__init__`(backend[, shots, seed_simulator, …])	Quantum Instance holds a Qiskit Terra backend as well as configuration for circuit transpilation and execution.
`assemble`(circuits)	assemble circuits
`cals_matrix`([qubit_index])	Get the stored calibration matrices and its timestamp.
`execute`(circuits[, had_transpiled])	A wrapper to interface with quantum backend.
`maybe_refresh_cals_matrix`([timestamp])	Calculate the time difference from the query of last time.
`reset_execution_results`()	Reset execution results
`set_config`(**kwargs)	Set configurations for the quantum instance.
`transpile`(circuits)	A wrapper to transpile circuits to allow algorithm access the transpiled circuits.

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.

assemble(circuits)[source]¶

assemble circuits

Return type: Qobj

property backend¶: Return BaseBackend backend object.

property backend_config¶: Getter of backend_config.

property backend_name¶: Return backend name.

property backend_options¶: Getter of backend_options.

cals_matrix(qubit_index=None)[source]¶

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.

property cals_matrix_refresh_period¶: returns matrix refresh period

property circuit_summary¶: Getter of circuit summary.

property compile_config¶: Getter of compile_config.

execute(circuits, had_transpiled=False)[source]¶

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

Returns

result object

Return type

Result

TODO: Maybe we can combine the circuits for the main ones and calibration circuits before: assembling to the qobj.

property is_local¶: Return True if backend is a local backend.

property is_simulator¶: Return True if backend is a simulator.

property is_statevector¶: Return True if backend is a statevector-type simulator.

maybe_refresh_cals_matrix(timestamp=None)[source]¶

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

property measurement_error_mitigation_cls¶: returns measurement error mitigation cls

property measurement_error_mitigation_shots¶: returns measurement error mitigation shots

property noise_config¶: Getter of noise_config.

property qjob_config¶: Getter of qjob_config.

reset_execution_results()[source]¶

Reset execution results

Return type: None

property run_config¶: Getter of run_config.

set_config(**kwargs)[source]¶: Set configurations for the quantum instance.

property skip_qobj_validation¶: checks if skip qobj validation

property time_taken¶

Accumulated time taken for execution.

Return type: float

transpile(circuits)[source]¶

A wrapper to transpile circuits to allow algorithm access the transpiled circuits. :param circuits: circuits to transpile :type circuits: Union[‘QuantumCircuit’, List[‘QuantumCircuit’]]

Returns

The transpiled circuits, it is always a list even though: the length is one.

Return type

List[‘QuantumCircuit’]