qiskit.ml.circuit.library.RawFeatureVector.save_expectation_value_variance

RawFeatureVector.save_expectation_value_variance(operator, qubits, label='expectation_value_variance', unnormalized=False, pershot=False, conditional=False)

Save the expectation value of a Hermitian operator.

Parameters

• operator (Pauli or SparsePauliOp or Operator) – a Hermitian operator.

• qubits (list) – circuit qubits to apply instruction.

• label (str) – the key for retrieving saved data from results.

• unnormalized (bool) – If True return save the unnormalized accumulated or conditional accumulated expectation value and variance over all shot [Default: False].

• pershot (bool) – if True save a list of expectation values and variances for each shot of the simulation rather than the average over all shots [Default: False].

• conditional (bool) – if True save the data conditional on the current classical register values [Default: False].

Returns

with attached instruction.

Return type

QuantumCircuit

Raises

ExtensionError – if the input operator is invalid or not Hermitian.

Note

This method appends a SaveExpectationValueVariance instruction to the quantum circuit.