def test_controlled_phase(self, tol):
"""Test the CZ symplectic transform."""
s = 0.543
S = controlled_phase(s)
# test that S = R_2(pi/2) CX(s) R_2(pi/2)^\dagger
R2 = block_diag(np.identity(2), rotation(np.pi/2))[:, [0, 2, 1, 3]][[0, 2, 1, 3]]
expected = R2 @ controlled_addition(s) @ R2.conj().T
assert S == pytest.approx(expected, abs=tol)
# test that S[x1, x2, p1, p2] -> [x1, x2, p1+sx2, p2+sx1]
x1 = 0.5432
x2 = -0.453
p1 = 0.154
p2 = -0.123
out = S @ np.array([x1, x2, p1, p2])*np.sqrt(2*hbar)
expected = np.array([x1, x2, p1+s*x2, p2+s*x1])*np.sqrt(2*hbar)
assert out == pytest.approx(expected, abs=tol)
def test_controlled_phase(self):
"""Test the CZ symplectic transform."""
self.logTestName()
s = 0.543
S = controlled_phase(s)
# test that S = R_2(pi/2) CX(s) R_2(pi/2)^\dagger
R2 = block_diag(np.identity(2), rotation(np.pi/2))[:, [0, 2, 1, 3]][[0, 2, 1, 3]]
expected = R2 @ controlled_addition(s) @ R2.conj().T
self.assertAllAlmostEqual(S, expected, delta=self.tol)
# test that S[x1, x2, p1, p2] -> [x1, x2, p1+sx2, p2+sx1]
x1 = 0.5432
x2 = -0.453
p1 = 0.154
p2 = -0.123
out = S @ np.array([x1, x2, p1, p2])*np.sqrt(2*hbar)
expected = np.array([x1, x2, p1+s*x2, p2+s*x1])*np.sqrt(2*hbar)
self.assertAllAlmostEqual(out, expected, delta=self.tol)