def test_hamiltonian_expectation_errors():
h = XXZ(nqubits=3, delta=0.5)
state = utils.random_numpy_complex((4, 4, 4))
with pytest.raises(ValueError):
h.expectation(state)
with pytest.raises(TypeError):
h.expectation("test")
def test_hamiltonian_expectation(numpy, trotter):
h = XXZ(nqubits=3, delta=0.5, numpy=numpy, trotter=trotter)
matrix = np.array(h.matrix)
state = utils.random_numpy_complex(8)
norm = (np.abs(state)**2).sum()
target_ev = (state.conj() * matrix.dot(state)).sum().real
np.testing.assert_allclose(h.expectation(state), target_ev)
np.testing.assert_allclose(h.expectation(state, True), target_ev / norm)
def test_hamiltonian_expectation(numpy, trotter, density_matrix):
h = XXZ(nqubits=3, delta=0.5, numpy=numpy, trotter=trotter)
matrix = np.array(h.matrix)
if density_matrix:
state = utils.random_numpy_complex((8, 8))
state = state + state.T.conj()
norm = np.trace(state)
target_ev = np.trace(matrix.dot(state)).real
else:
state = utils.random_numpy_complex(8)
norm = np.sum(np.abs(state)**2)
target_ev = np.sum(state.conj() * matrix.dot(state)).real
np.testing.assert_allclose(h.expectation(state), target_ev)
np.testing.assert_allclose(h.expectation(state, True), target_ev / norm)