def test_two_qubit_decomposition_1_cnot(self, U, wires):
"""Test that a two-qubit matrix using one CNOT is correctly decomposed."""
U = _convert_to_su4(np.array(U))
assert _compute_num_cnots(U) == 1
obtained_decomposition = two_qubit_decomposition(U, wires=wires)
assert len(obtained_decomposition) == 5
with qml.tape.QuantumTape() as tape:
for op in obtained_decomposition:
qml.apply(op)
obtained_matrix = get_unitary_matrix(tape, wire_order=wires)()
assert check_matrix_equivalence(U, obtained_matrix, atol=1e-7)
def test_two_qubit_decomposition_tensor_products(self, U_pair, wires):
"""Test that a two-qubit tensor product matrix is correctly decomposed."""
U = _convert_to_su4(
qml.math.kron(np.array(U_pair[0]), np.array(U_pair[1])))
assert _compute_num_cnots(U) == 0
obtained_decomposition = two_qubit_decomposition(U, wires=wires)
assert len(obtained_decomposition) == 2
with qml.tape.QuantumTape() as tape:
for op in obtained_decomposition:
qml.apply(op)
obtained_matrix = get_unitary_matrix(tape, wire_order=wires)()
assert check_matrix_equivalence(U, obtained_matrix, atol=1e-7)
def test_two_qubit_decomposition_3_cnots(self, U, wires):
"""Test that a two-qubit matrix using 3 CNOTs is correctly decomposed."""
U = _convert_to_su4(np.array(U))
assert _compute_num_cnots(U) == 3
obtained_decomposition = two_qubit_decomposition(U, wires=wires)
assert len(obtained_decomposition) == 10
with qml.tape.QuantumTape() as tape:
for op in obtained_decomposition:
qml.apply(op)
obtained_matrix = get_unitary_matrix(tape, wire_order=wires)()
# We check with a slightly great tolerance threshold here simply because the
# test matrices were copied in here with reduced precision.
assert check_matrix_equivalence(U, obtained_matrix, atol=1e-7)