def test_keep_layout(self):
"""After a swap, the following gates also change the wires.
qr0:---.---[H]--
|
qr1:---|--------
|
qr2:--(+)-------
CouplingMap map: [0]--[1]--[2]
qr0:--X-----------
|
qr1:--X---.--[H]--
|
qr2:-----(+)------
"""
coupling = CouplingMap([[1, 0], [1, 2]])
qr = QuantumRegister(3, 'q')
circuit = QuantumCircuit(qr)
circuit.cx(qr[0], qr[2])
circuit.h(qr[0])
dag = circuit_to_dag(circuit)
expected = QuantumCircuit(qr)
expected.swap(qr[0], qr[1])
expected.cx(qr[1], qr[2])
expected.h(qr[1])
pass_ = BasicSwap(coupling)
after = pass_.run(dag)
self.assertEqual(circuit_to_dag(expected), after)
def test_a_single_swap(self):
""" Adding a swap
q0:-------
q1:--(+)--
|
q2:---.---
CouplingMap map: [1]--[0]--[2]
q0:--X---.---
| |
q1:--X---|---
|
q2:-----(+)--
"""
coupling = CouplingMap([[0, 1], [0, 2]])
qr = QuantumRegister(3, 'q')
circuit = QuantumCircuit(qr)
circuit.cx(qr[1], qr[2])
dag = circuit_to_dag(circuit)
expected = QuantumCircuit(qr)
expected.swap(qr[1], qr[0])
expected.cx(qr[0], qr[2])
pass_ = BasicSwap(coupling)
after = pass_.run(dag)
self.assertEqual(circuit_to_dag(expected), after)
def test_initial_layout_in_different_qregs(self):
""" Using an initial_layout, and with several qregs
0:q1_0:--(+)--
|
1:q0_0:---|---
|
2:q2_0:---.---
CouplingMap map: [0]--[1]--[2]
0:q1_0:--X-------
|
1:q0_0:--X---.---
|
2:q2_0:-----(+)--
"""
coupling = CouplingMap([[0, 1], [1, 2]])
qr0 = QuantumRegister(1, 'q0')
qr1 = QuantumRegister(1, 'q1')
qr2 = QuantumRegister(1, 'q2')
circuit = QuantumCircuit(qr0, qr1, qr2)
circuit.cx(qr1[0], qr2[0])
dag = circuit_to_dag(circuit)
layout = Layout({qr1[0]: 0, qr0[0]: 1, qr2[0]: 2})
expected = QuantumCircuit(qr0, qr1, qr2)
expected.swap(qr1[0], qr0[0])
expected.cx(qr0[0], qr2[0])
pass_ = BasicSwap(coupling, initial_layout=layout)
after = pass_.run(dag)
self.assertEqual(circuit_to_dag(expected), after)
def test_initial_layout(self):
""" Using an initial_layout
0:q1:--(+)--
|
1:q0:---|---
|
2:q2:---.---
CouplingMap map: [0]--[1]--[2]
0:q1:--X-------
|
1:q0:--X---.---
|
2:q2:-----(+)--
"""
coupling = CouplingMap([[0, 1], [1, 2]])
qr = QuantumRegister(3, 'q')
circuit = QuantumCircuit(qr)
circuit.cx(qr[1], qr[2])
dag = circuit_to_dag(circuit)
layout = Layout({qr[1]: 0, qr[0]: 1, qr[2]: 2})
expected = QuantumCircuit(qr)
expected.swap(qr[1], qr[0])
expected.cx(qr[0], qr[2])
pass_ = BasicSwap(coupling, initial_layout=layout)
after = pass_.run(dag)
self.assertEqual(circuit_to_dag(expected), after)
def test_far_swap_with_gate_the_middle(self):
""" A far swap with a gate in the middle.
q0:--(+)-------.--
| |
q1:---|--------|--
|
q2:---|--------|--
| |
q3:---.--[H]--(+)-
CouplingMap map: [0]--[1]--[2]--[3]
q0:-------(+)-------.---
| |
q1:-----X--.--[H]--(+)--
|
q2:--X--X---------------
|
q3:--X------------------
"""
coupling = CouplingMap([[0, 1], [1, 2], [2, 3]])
qr = QuantumRegister(4, 'q')
circuit = QuantumCircuit(qr)
circuit.cx(qr[3], qr[0])
circuit.h(qr[3])
circuit.cx(qr[0], qr[3])
dag = circuit_to_dag(circuit)
expected = QuantumCircuit(qr)
expected.swap(qr[3], qr[2])
expected.swap(qr[2], qr[1])
expected.cx(qr[1], qr[0])
expected.h(qr[1])
expected.cx(qr[0], qr[1])
pass_ = BasicSwap(coupling)
after = pass_.run(dag)
self.assertEqual(circuit_to_dag(expected), after)
def test_far_swap(self):
""" A far swap that affects coming CXs.
qr0:--(+)---.--
| |
qr1:---|----|--
| |
qr2:---|----|--
| |
qr3:---.---(+)-
CouplingMap map: [0]--[1]--[2]--[3]
qr0:--X--------------
|
qr1:--X--X-----------
|
qr2:-----X--(+)---.--
| |
qr3:---------.---(+)-
"""
coupling = CouplingMap([[0, 1], [1, 2], [2, 3]])
qr = QuantumRegister(4, 'q')
circuit = QuantumCircuit(qr)
circuit.cx(qr[0], qr[3])
circuit.cx(qr[3], qr[0])
dag = circuit_to_dag(circuit)
expected = QuantumCircuit(qr)
expected.swap(qr[0], qr[1])
expected.swap(qr[1], qr[2])
expected.cx(qr[2], qr[3])
expected.cx(qr[3], qr[2])
pass_ = BasicSwap(coupling)
after = pass_.run(dag)
self.assertEqual(circuit_to_dag(expected), after)
def test_trivial_case(self):
"""No need to have any swap, the CX are distance 1 to each other
q0:--(+)-[U]-(+)-
| |
q1:---.-------|--
|
q2:-----------.--
CouplingMap map: [1]--[0]--[2]
"""
coupling = CouplingMap([[0, 1], [0, 2]])
qr = QuantumRegister(3, 'q')
circuit = QuantumCircuit(qr)
circuit.cx(qr[0], qr[1])
circuit.h(qr[0])
circuit.cx(qr[0], qr[2])
dag = circuit_to_dag(circuit)
pass_ = BasicSwap(coupling)
after = pass_.run(dag)
self.assertEqual(dag, after)
def test_trivial_in_same_layer(self):
""" No need to have any swap, two CXs distance 1 to each other, in the same layer
q0:--(+)--
|
q1:---.---
q2:--(+)--
|
q3:---.---
CouplingMap map: [0]--[1]--[2]--[3]
"""
coupling = CouplingMap([[0, 1], [1, 2], [2, 3]])
qr = QuantumRegister(4, 'q')
circuit = QuantumCircuit(qr)
circuit.cx(qr[2], qr[3])
circuit.cx(qr[0], qr[1])
dag = circuit_to_dag(circuit)
pass_ = BasicSwap(coupling)
after = pass_.run(dag)
self.assertEqual(dag, after)
def test_swap_between_qregs(self):
""" Adding a swap affecting different qregs
virtual physical
qr0_0: [0] -------
qr1_0: [1] --(+)--
|
qr1_1: [2] ---.---
CouplingMap map: [1]--[0]--[2]
virtual physical
qr0_0: [0] --X-(+)--
| |
qr1_0: [1] --X--|---
|
qr1_1: [2] -----.---
"""
coupling = CouplingMap([[0, 1], [0, 2]])
qr0 = QuantumRegister(1, 'qr0')
qr1 = QuantumRegister(2, 'qr1')
circuit = QuantumCircuit(qr0, qr1)
circuit.cx(qr1[0], qr1[1])
dag = circuit_to_dag(circuit)
expected = QuantumCircuit(qr0, qr1)
expected.swap(qr1[0], qr0[0])
expected.cx(qr0[0], qr1[1])
pass_ = BasicSwap(coupling)
after = pass_.run(dag)
self.assertEqual(circuit_to_dag(expected), after)
