def test_optimize_cliffords(self):
"""Test OptimizeCliffords pass."""
rng = np.random.default_rng(1234)
for _ in range(20):
# Create several random Cliffords
cliffs = [random_clifford(3, rng) for _ in range(5)]
# The first circuit contains these cliffords
qc1 = QuantumCircuit(5)
for cliff in cliffs:
qc1.append(cliff, [4, 0, 2])
self.assertEqual(qc1.count_ops()["clifford"], 5)
# The second circuit is obtained by running the OptimizeCliffords pass.
qc2 = PassManager(OptimizeCliffords()).run(qc1)
self.assertEqual(qc2.count_ops()["clifford"], 1)
# The third circuit contains the decompositions of Cliffods.
qc3 = QuantumCircuit(5)
for cliff in cliffs:
qc3.append(cliff.to_circuit(), [4, 0, 2])
self.assertNotIn("clifford", qc3.count_ops())
# Check that qc1, qc2 and qc3 and their decompositions are all equivalent.
self.assertTrue(Operator(qc1).equiv(Operator(qc1.decompose())))
self.assertTrue(Operator(qc2).equiv(Operator(qc2.decompose())))
self.assertTrue(Operator(qc3).equiv(Operator(qc3.decompose())))
self.assertTrue(Operator(qc1).equiv(Operator(qc2)))
self.assertTrue(Operator(qc1).equiv(Operator(qc3)))
def test_can_combine_cliffords(self):
"""Test that we can combine a pair of Cliffords over the same qubits
using OptimizeCliffords transpiler pass."""
cliff1 = self.create_cliff1()
cliff2 = self.create_cliff2()
cliff3 = self.create_cliff3()
# Create a circuit with two consective cliffords
qc1 = QuantumCircuit(4)
qc1.append(cliff1, [3, 1, 2])
qc1.append(cliff2, [3, 1, 2])
self.assertEqual(qc1.count_ops()["clifford"], 2)
# Run OptimizeCliffords pass, and check that only one Clifford remains
qc1opt = PassManager(OptimizeCliffords()).run(qc1)
self.assertEqual(qc1opt.count_ops()["clifford"], 1)
# Create the expected circuit
qc2 = QuantumCircuit(4)
qc2.append(cliff3, [3, 1, 2])
# Check that all possible operators are equal
self.assertTrue(Operator(qc1).equiv(Operator(qc1.decompose())))
self.assertTrue(Operator(qc1opt).equiv(Operator(qc1opt.decompose())))
self.assertTrue(Operator(qc1).equiv(Operator(qc1opt)))
self.assertTrue(Operator(qc2).equiv(Operator(qc2.decompose())))
self.assertTrue(Operator(qc1opt).equiv(Operator(qc2)))
