qiskit.algorithms.PhaseEstimationScale.from_pauli_sum¶

classmethod PhaseEstimationScale.from_pauli_sum(pauli_sum)[source]¶

Create a PhaseEstimationScale from a SummedOp representing a sum of Pauli Operators.

It is assumed that the pauli_sum is the sum of PauliOp objects. The bound on the absolute value of the eigenvalues of the sum is obtained as the sum of the absolute values of the coefficients of the terms. This is the best bound available in the generic case. A PhaseEstimationScale object is instantiated using this bound.

Parameters: pauli_sum (SummedOp | PauliSumOp | SparsePauliOp | Operator) -- A SummedOp whose terms are PauliOp objects.
Raises: ValueError -- if pauli_sum is not a sum of Pauli operators.
Returns: A PhaseEstimationScale object
Return type: 'PhaseEstimationScale' | float