def test_cat_state_error(self, setup_eng, cutoff, bsize, pure, tol):
"""Test that the cat_state function raises an error for a complex
argument"""
alpha = 0.3j + 0.4
p = 1
with pytest.raises(ValueError, match="cannot be complex"):
ket = utils.cat_state(alpha, p, fock_dim=cutoff)
def test_odd_cat_state(self, tol):
"""test correct even cat state returned"""
a = 0.212
cutoff = 10
p = 1
state = utils.cat_state(a, p, fock_dim=cutoff)
n = np.arange(cutoff)
expected = np.exp(-0.5 * np.abs(a)**2) * a**n / np.sqrt(
fac(n)) - np.exp(-0.5 * np.abs(-a)**2) * (-a)**n / np.sqrt(fac(n))
expected /= np.linalg.norm(expected)
assert np.allclose(state, expected, atol=tol, rtol=0)
def test_odd_cat_state(self, a, cutoff, tol):
"""test correct odd cat state returned"""
p = 1
state = utils.cat_state(a, p, fock_dim=cutoff)
# For the analytic expression, cast the integer parameter to float so
# that there's no overflow
a = float(a)
n = np.arange(cutoff)
expected = np.exp(-0.5 * np.abs(a)**2) * a**n / np.sqrt(
fac(n)) - np.exp(-0.5 * np.abs(-a)**2) * (-a)**n / np.sqrt(fac(n))
expected /= np.linalg.norm(expected)
assert np.allclose(state, expected, atol=tol, rtol=0)
def test_cat_state(self, setup_eng, hbar, cutoff, bsize, pure, tol):
"""Test cat state function matches Fock backends"""
eng, prog = setup_eng(1)
a = 0.32 + 0.1j
p = 0.43
with prog.context as q:
ops.Catstate(a, p) | q[0]
state = eng.run(prog)
ket = utils.cat_state(a, p, fock_dim=cutoff)
if not pure:
expected = state.dm()
ket = np.tile(np.outer(ket, ket.conj()), (bsize, 1, 1))
else:
expected = state.ket()
ket = np.tile(ket, (bsize, 1))
assert np.allclose(expected, ket, atol=tol, rtol=0)
