def test_crx_decomposition_correctness(self, phi, tol): """Test that the decomposition of the controlled X qubit rotation is correct""" expected = CRotx(phi) obtained = np.kron(I, Rotz(-np.pi / 2)) @ CNOT @ np.kron( I, Roty(-phi / 2)) @ CNOT @ np.kron(I, Roty(phi / 2)) @ np.kron( I, Rotz(np.pi / 2)) assert np.allclose(expected, obtained, atol=tol, rtol=0)
def test_qnode_fanout(self, qubit_device_1_wire, tol): """Tests that qnodes can compute the correct function when the same parameter is used in multiple gates.""" @qml.qnode(qubit_device_1_wire, interface='torch') def circuit(reused_param, other_param): qml.RX(reused_param, wires=[0]) qml.RZ(other_param, wires=[0]) qml.RX(reused_param, wires=[0]) return qml.expval(qml.PauliZ(0)) thetas = torch.linspace(-2 * np.pi, 2 * np.pi, 7) for reused_param in thetas: for theta in thetas: other_param = theta**2 / 11 y_eval = circuit(reused_param, other_param) Rx = Rotx(reused_param.numpy()) Rz = Rotz(other_param.numpy()) zero_state = np.array([1., 0.]) final_state = (Rx @ Rz @ Rx @ zero_state) y_true = expZ(final_state) assert np.allclose(y_eval, y_true, atol=tol, rtol=0)
def test_multiple_expectation_different_wires(self, qubit_device_2_wires, tol): """Tests that qnodes return multiple expectation values.""" a, b, c = torch.tensor(0.5), torch.tensor(0.54), torch.tensor(0.3) @qml.qnode(qubit_device_2_wires, interface='torch') def circuit(x, y, z): qml.RX(x, wires=[0]) qml.RZ(y, wires=[0]) qml.CNOT(wires=[0, 1]) qml.RY(y, wires=[0]) qml.RX(z, wires=[0]) return qml.expval(qml.PauliY(0)), qml.expval(qml.PauliZ(1)) res = circuit(a, b, c) out_state = np.kron(Rotx(c.numpy()), I) @ np.kron(Roty(b.numpy()), I) @ CNOT \ @ np.kron(Rotz(b.numpy()), I) @ np.kron(Rotx(a.numpy()), I) @ np.array([1, 0, 0, 0]) ex0 = np.vdot(out_state, np.kron(Y, I) @ out_state) ex1 = np.vdot(out_state, np.kron(I, Z) @ out_state) ex = np.array([ex0, ex1]) assert np.allclose(ex, res.numpy(), atol=tol, rtol=0)