openfermion.linalg.variance

Compute variance of operator with a state.

operator(scipy.sparse.spmatrix or scipy.sparse.linalg.LinearOperator): The operator whose expectation value is desired. state(numpy.ndarray or scipy.sparse.spmatrix): A numpy array representing a pure state or a sparse matrix representing a density matrix.

A complex number giving the variance.

ValueError Input state has invalid format.