"""Helper gates for circuit knitting."""
from qiskit import QuantumCircuit, transpile
from qiskit.circuit import CircuitInstruction, Gate
# define the cut location marker
cut = QuantumCircuit(1, name="Cut")
cut = cut.to_instruction(label="Cut")
cut.definition = None
cutCZ = QuantumCircuit(2, name="CutCZ")
cutCZ = cutCZ.to_instruction(label="CutCZ")
cutCZ.definition = None
[docs]
def cutGate(gate: Gate, control: int, target: int) -> dict:
"""Return a cutCZ circuit with the same parameters as the input gate."""
if gate.num_qubits != 2:
raise ValueError("Input gate must be a 2-qubit gate.")
if control == target:
raise ValueError("Control and target qubits must be different.")
if control < 0 or target < 0:
raise ValueError("Control and target qubits must be non-negative.")
qc = QuantumCircuit(2, name=f"cut{gate.name.upper()}")
if control > target:
loccontrol = 1
loctarget = 0
else:
loccontrol = 0
loctarget = 1
qc.append(gate, [loccontrol, loctarget])
tr = transpile(qc, basis_gates=["cz", "r", "h", "s", "sdg", "x", "y", "z"])
for ind, instr in enumerate(tr.data):
if instr.operation.name == "cz":
tr.data.pop(ind)
test = CircuitInstruction(
operation=cutCZ,
qubits=tr.qubits,
)
tr.data.insert(ind, test)
return {"instruction": tr.to_instruction(label="CutGate"),
"qargs":[control, target]}
# define measurements for different bases
xmeas = QuantumCircuit(1, 1, name="x-meas")
xmeas.h(0)
xmeas.measure(0, 0)
ymeas = QuantumCircuit(1, 1, name="y-meas")
ymeas.sdg(0)
ymeas.h(0)
ymeas.measure(0, 0)
idmeas = QuantumCircuit(1, name="id-meas")
idmeas.id(0)
zmeas = QuantumCircuit(1, 1, name="z-meas")
zmeas.measure(0, 0)
# define initialization operations
zero_init = QuantumCircuit(1, name="0-init")
zero_init.id(0)
one_init = QuantumCircuit(1, name="1-init")
one_init.x(0)
plus_init = QuantumCircuit(1, name="'+'-init")
plus_init.h(0)
minus_init = QuantumCircuit(1, name="'-'-init")
minus_init.h(0)
minus_init.z(0)
i_plus_init = QuantumCircuit(1, name="'i+'-init")
i_plus_init.h(0)
i_plus_init.s(0)
i_minus_init = QuantumCircuit(1, name="'i-'-init")
i_minus_init.h(0)
i_minus_init.z(0)
i_minus_init.s(0)
sdg = QuantumCircuit(1, 1, name="sdg")
sdg.sdg(0)
s = QuantumCircuit(1, 1, name="s")
s.s(0)
z = QuantumCircuit(1, 1, name="z")
z.z(0)
sdg_meas = QuantumCircuit(1, 1, name="sdg_meas")
sdg_meas.sdg(0)
sdg_meas.measure(0, 0)
