def test_objective_function(self):
"""Test if ``objective`` functions priorities metrics correctly."""
qc = QuantumCircuit(4)
qc.dcx(0, 1)
qc.cx(2, 3)
qc.dcx(0, 2)
qc.cx(1, 3)
qc.dcx(0, 1)
qc.cx(2, 3)
coupling = CouplingMap(FakeLima().configuration().coupling_map)
dep_opt = BIPMapping(coupling,
objective="depth",
qubit_subset=[0, 1, 3, 4])(qc)
err_opt = BIPMapping(
coupling,
objective="gate_error",
qubit_subset=[0, 1, 3, 4],
backend_prop=FakeLima().properties(),
)(qc)
# depth = number of su4 layers (mirrored gates have to be consolidated as single su4 gates)
pm_ = PassManager(
[Collect2qBlocks(),
ConsolidateBlocks(basis_gates=["cx"])])
dep_opt = pm_.run(dep_opt)
err_opt = pm_.run(err_opt)
self.assertLessEqual(dep_opt.depth(), err_opt.depth())
# count CNOTs after synthesized
dep_opt = UnitarySynthesis(basis_gates=["cx"])(dep_opt)
err_opt = UnitarySynthesis(basis_gates=["cx"])(err_opt)
self.assertGreater(dep_opt.count_ops()["cx"],
err_opt.count_ops()["cx"])
def test_swaps_in_dummy_steps(self):
"""Test the case when swaps are inserted in dummy steps."""
circuit = QuantumCircuit(4)
circuit.cx(0, 1)
circuit.cx(2, 3)
circuit.h([0, 1, 2, 3])
circuit.barrier()
circuit.cx(0, 3)
circuit.cx(1, 2)
circuit.barrier()
circuit.cx(0, 2)
circuit.cx(1, 3)
coupling = CouplingMap.from_line(4)
property_set = {}
actual = BIPMapping(coupling, objective="depth")(circuit, property_set)
self.assertEqual(7, actual.depth())
CheckMap(coupling)(actual, property_set)
self.assertTrue(property_set["is_swap_mapped"])
# no swaps before the first barrier
for inst, _, _ in actual.data:
if isinstance(inst, Barrier):
break
self.assertFalse(isinstance(inst, SwapGate))
def test_no_swap_multi_layer(self):
"""Can find the best layout for a circuit with multiple layers."""
coupling = CouplingMap([[0, 1], [1, 2], [2, 3]])
qr = QuantumRegister(4, name="qr")
circuit = QuantumCircuit(qr)
circuit.cx(qr[1], qr[0])
circuit.cx(qr[0], qr[3])
property_set = {}
actual = BIPMapping(coupling, objective="depth")(circuit, property_set)
self.assertEqual(2, actual.depth())
CheckMap(coupling)(actual, property_set)
self.assertTrue(property_set["is_swap_mapped"])
def test_multi_cregs(self):
"""Test for multiple ClassicalRegisters."""
# ┌───┐ ░ ┌─┐
# qr_0: ──■────────────┤ X ├─░─┤M├─────────
# ┌─┴─┐ ┌───┐└─┬─┘ ░ └╥┘┌─┐
# qr_1: ┤ X ├──■──┤ H ├──■───░──╫─┤M├──────
# └───┘┌─┴─┐└───┘ ░ ║ └╥┘┌─┐
# qr_2: ──■──┤ X ├───────────░──╫──╫─┤M├───
# ┌─┴─┐└───┘ ░ ║ ║ └╥┘┌─┐
# qr_3: ┤ X ├────────────────░──╫──╫──╫─┤M├
# └───┘ ░ ║ ║ ║ └╥┘
# c: 2/════════════════════════╩══╬══╩══╬═
# 0 ║ 1 ║
# ║ ║
# d: 2/═══════════════════════════╩═════╩═
# 0 1
qr = QuantumRegister(4, "qr")
cr1 = ClassicalRegister(2, "c")
cr2 = ClassicalRegister(2, "d")
circuit = QuantumCircuit(qr, cr1, cr2)
circuit.cx(qr[0], qr[1])
circuit.cx(qr[2], qr[3])
circuit.cx(qr[1], qr[2])
circuit.h(qr[1])
circuit.cx(qr[1], qr[0])
circuit.barrier(qr)
circuit.measure(qr[0], cr1[0])
circuit.measure(qr[1], cr2[0])
circuit.measure(qr[2], cr1[1])
circuit.measure(qr[3], cr2[1])
coupling = CouplingMap([[0, 1], [0, 2], [2, 3]]) # linear [1, 0, 2, 3]
property_set = {}
actual = BIPMapping(coupling, objective="depth")(circuit, property_set)
self.assertEqual(5, actual.depth())
CheckMap(coupling)(actual, property_set)
self.assertTrue(property_set["is_swap_mapped"])
def test_multi_cregs(self):
"""Test for multiple ClassicalRegisters."""
qr = QuantumRegister(4, "qr")
cr1 = ClassicalRegister(2, "c")
cr2 = ClassicalRegister(2, "d")
circuit = QuantumCircuit(qr, cr1, cr2)
circuit.cx(qr[0], qr[1])
circuit.cx(qr[2], qr[3])
circuit.cx(qr[1], qr[2])
circuit.h(qr[1])
circuit.cx(qr[1], qr[0])
circuit.barrier(qr)
circuit.measure(qr[0], cr1[0])
circuit.measure(qr[1], cr2[0])
circuit.measure(qr[2], cr1[1])
circuit.measure(qr[3], cr2[1])
coupling = CouplingMap([[0, 1], [0, 2], [2, 3]]) # linear [1, 0, 2, 3]
property_set = {}
actual = BIPMapping(coupling, objective="depth")(circuit, property_set)
self.assertEqual(5, actual.depth())
CheckMap(coupling)(actual, property_set)
self.assertTrue(property_set["is_swap_mapped"])
def test_swaps_in_dummy_steps(self):
"""Test the case when swaps are inserted in dummy steps."""
# ┌───┐ ░ ░
# q_0: ──■──┤ H ├─░───■────────░───■───────
# ┌─┴─┐├───┤ ░ │ ░ │
# q_1: ┤ X ├┤ H ├─░───┼────■───░───┼────■──
# └───┘├───┤ ░ │ ┌─┴─┐ ░ ┌─┴─┐ │
# q_2: ──■──┤ H ├─░───┼──┤ X ├─░─┤ X ├──┼──
# ┌─┴─┐├───┤ ░ ┌─┴─┐└───┘ ░ └───┘┌─┴─┐
# q_3: ┤ X ├┤ H ├─░─┤ X ├──────░──────┤ X ├
# └───┘└───┘ ░ └───┘ ░ └───┘
circuit = QuantumCircuit(4)
circuit.cx(0, 1)
circuit.cx(2, 3)
circuit.h([0, 1, 2, 3])
circuit.barrier()
circuit.cx(0, 3)
circuit.cx(1, 2)
circuit.barrier()
circuit.cx(0, 2)
circuit.cx(1, 3)
coupling = CouplingMap.from_line(4)
property_set = {}
actual = BIPMapping(coupling, objective="depth")(circuit, property_set)
self.assertEqual(7, actual.depth())
CheckMap(coupling)(actual, property_set)
self.assertTrue(property_set["is_swap_mapped"])
# no swaps before the first barrier
for inst, _, _ in actual.data:
if isinstance(inst, Barrier):
break
self.assertFalse(isinstance(inst, SwapGate))