def test_ghz_2_3():
"""Produces the 3-qubit GHZ state: `1/sqrt(2) * (|000> + |111>)`."""
e_0, e_1 = basis(2, 0), basis(2, 1)
expected_res = 1 / np.sqrt(2) * (tensor(e_0, e_0, e_0) +
tensor(e_1, e_1, e_1))
res = ghz(2, 3).toarray()
bool_mat = np.isclose(res, expected_res)
np.testing.assert_equal(np.all(bool_mat), True)
def test_ghz_4_7():
r"""
The following generates the following GHZ state in `(C^4)^{\otimes 7}`.
`1/sqrt(30) * (|0000000> + 2|1111111> + 3|2222222> + 4|3333333>)`.
"""
e0_4 = np.array([[1], [0], [0], [0]])
e1_4 = np.array([[0], [1], [0], [0]])
e2_4 = np.array([[0], [0], [1], [0]])
e3_4 = np.array([[0], [0], [0], [1]])
expected_res = (1 / np.sqrt(30) *
(tensor(e0_4, e0_4, e0_4, e0_4, e0_4, e0_4, e0_4) +
2 * tensor(e1_4, e1_4, e1_4, e1_4, e1_4, e1_4, e1_4) +
3 * tensor(e2_4, e2_4, e2_4, e2_4, e2_4, e2_4, e2_4) +
4 * tensor(e3_4, e3_4, e3_4, e3_4, e3_4, e3_4, e3_4)))
res = ghz(4, 7, np.array([1, 2, 3, 4]) / np.sqrt(30)).toarray()
bool_mat = np.isclose(res, expected_res)
np.testing.assert_equal(np.all(bool_mat), True)
def test_ghz_invalid_coeff():
"""Tests for invalid coefficients."""
with np.testing.assert_raises(ValueError):
ghz(2, 3, [1, 2, 3, 4, 5])
def test_ghz_invalid_qubits():
"""Tests for invalid number of qubits."""
with np.testing.assert_raises(ValueError):
ghz(2, 1)
def test_ghz_invalid_dim():
"""Tests for invalid dimensions."""
with np.testing.assert_raises(ValueError):
ghz(1, 2)