def test_mcx_gates(self, num_ctrl_qubits):
"""Test the mcx gates."""
backend = BasicAer.get_backend('statevector_simulator')
reference = np.zeros(2 ** (num_ctrl_qubits + 1))
reference[-1] = 1
for gate in [MCXGrayCode(num_ctrl_qubits),
MCXRecursive(num_ctrl_qubits),
MCXVChain(num_ctrl_qubits, False),
MCXVChain(num_ctrl_qubits, True),
]:
with self.subTest(gate=gate):
circuit = QuantumCircuit(gate.num_qubits)
if num_ctrl_qubits > 0:
circuit.x(list(range(num_ctrl_qubits)))
circuit.append(gate, list(range(gate.num_qubits)), [])
statevector = execute(circuit, backend).result().get_statevector()
# account for ancillas
if hasattr(gate, 'num_ancilla_qubits') and gate.num_ancilla_qubits > 0:
corrected = np.zeros(2 ** (num_ctrl_qubits + 1), dtype=complex)
for i, statevector_amplitude in enumerate(statevector):
i = int(bin(i)[2:].zfill(circuit.num_qubits)[gate.num_ancilla_qubits:], 2)
corrected[i] += statevector_amplitude
statevector = corrected
np.testing.assert_array_almost_equal(statevector.real, reference)
def test_cnot(self):
"""Test different cnot gates (ccnot, mcx, etc)"""
qr = QuantumRegister(6, "q")
circuit = QuantumCircuit(qr)
circuit.x(0)
circuit.cx(0, 1)
circuit.ccx(0, 1, 2)
circuit.append(XGate().control(3, ctrl_state="010"), [qr[2], qr[3], qr[0], qr[1]])
circuit.append(MCXGate(num_ctrl_qubits=3, ctrl_state="101"), [qr[0], qr[1], qr[2], qr[4]])
circuit.append(MCXVChain(3, dirty_ancillas=True), [qr[0], qr[1], qr[2], qr[3], qr[5]])
self.circuit_drawer(circuit, filename="cnot.png")