PauliExpectation

class PauliExpectation(group_paulis=True)

Bases: qiskit.aqua.operators.expectations.expectation_base.ExpectationBase

An Expectation converter for Pauli-basis observables by changing Pauli measurements to a diagonal ({Z, I}^n) basis and appending circuit post-rotations to the measured state function. Optionally groups the Paulis with the same post-rotations (those that commute with one another, or form Abelian groups) into single measurements to reduce circuit execution overhead.

Parameters

group_paulis (bool) – Whether to group the Pauli measurements into commuting sums, which all have the same diagonalizing circuit.

Methods

compute_variance	Compute the variance of the expectation estimator.
convert	Accepts an Operator and returns a new Operator with the Pauli measurements replaced by diagonal Pauli post-rotation based measurements so they can be evaluated by sampling and averaging.