def test_open_control_cy_unrolling(self):
"""test unrolling of open control gates when gate is in basis"""
qc = QuantumCircuit(2)
qc.cy(0, 1, ctrl_state=0)
dag = circuit_to_dag(qc)
unroller = Unroller(['u3', 'cy'])
uqc = dag_to_circuit(unroller.run(dag))
ref_circuit = QuantumCircuit(2)
ref_circuit.u3(np.pi, 0, np.pi, 0)
ref_circuit.cy(0, 1)
ref_circuit.u3(np.pi, 0, np.pi, 0)
self.assertEqual(uqc, ref_circuit)
def decompose(self):
"""Call a decomposition pass on this circuit,
to decompose one level (shallow decompose).
Returns:
QuantumCircuit: a circuit one level decomposed
"""
from qiskit.transpiler.passes.decompose import Decompose
from qiskit.converters.circuit_to_dag import circuit_to_dag
from qiskit.converters.dag_to_circuit import dag_to_circuit
pass_ = Decompose()
decomposed_dag = pass_.run(circuit_to_dag(self))
return dag_to_circuit(decomposed_dag)
def test_composite(self):
"""Test composite gate count."""
qreg = QuantumRegister(self.num_ctrl + self.num_target)
qc = QuantumCircuit(qreg, name='composite')
qc.append(self.grx.control(self.num_ctrl), qreg)
qc.append(self.gry.control(self.num_ctrl), qreg)
qc.append(self.gry, qreg[0:self.gry.num_qubits])
qc.append(self.grz.control(self.num_ctrl), qreg)
dag = circuit_to_dag(qc)
unroller = Unroller(['u3', 'cx'])
uqc = dag_to_circuit(unroller.run(dag))
self.log.info('%s gate count: %d', uqc.name, uqc.size())
self.assertTrue(uqc.size() <= 93) # this limit could be changed
def test_rotation_gates(self):
"""Test controlled rotation gates"""
import qiskit.extensions.standard.u1 as u1
import qiskit.extensions.standard.rx as rx
import qiskit.extensions.standard.ry as ry
import qiskit.extensions.standard.rz as rz
num_ctrl = 2
num_target = 1
qreg = QuantumRegister(num_ctrl + num_target)
theta = pi / 2
gu1 = u1.U1Gate(theta)
grx = rx.RXGate(theta)
gry = ry.RYGate(theta)
grz = rz.RZGate(theta)
ugu1 = ac._unroll_gate(gu1, ['u1', 'u3', 'cx'])
ugrx = ac._unroll_gate(grx, ['u1', 'u3', 'cx'])
ugry = ac._unroll_gate(gry, ['u1', 'u3', 'cx'])
ugrz = ac._unroll_gate(grz, ['u1', 'u3', 'cx'])
ugrz.params = grz.params
cgu1 = ugu1.control(num_ctrl)
cgrx = ugrx.control(num_ctrl)
cgry = ugry.control(num_ctrl)
cgrz = ugrz.control(num_ctrl)
for gate, cgate in zip([gu1, grx, gry, grz], [cgu1, cgrx, cgry, cgrz]):
with self.subTest(i=gate.name):
if gate.name == 'rz':
iden = Operator.from_label('I')
zgen = Operator.from_label('Z')
op_mat = (np.cos(0.5 * theta) * iden -
1j * np.sin(0.5 * theta) * zgen).data
else:
op_mat = Operator(gate).data
ref_mat = Operator(cgate).data
cop_mat = _compute_control_matrix(op_mat, num_ctrl)
self.assertTrue(
matrix_equal(cop_mat, ref_mat, ignore_phase=True))
cqc = QuantumCircuit(num_ctrl + num_target)
cqc.append(cgate, cqc.qregs[0])
dag = circuit_to_dag(cqc)
unroller = Unroller(['u3', 'cx'])
uqc = dag_to_circuit(unroller.run(dag))
self.log.info('%s gate count: %d', cgate.name, uqc.size())
self.log.info('\n%s', str(uqc))
# these limits could be changed
if gate.name == 'ry':
self.assertTrue(uqc.size() <= 32)
elif gate.name == 'rz':
self.assertTrue(uqc.size() <= 40)
else:
self.assertTrue(uqc.size() <= 20)
qc = QuantumCircuit(qreg, name='composite')
qc.append(grx.control(num_ctrl), qreg)
qc.append(gry.control(num_ctrl), qreg)
qc.append(gry, qreg[0:gry.num_qubits])
qc.append(grz.control(num_ctrl), qreg)
dag = circuit_to_dag(qc)
unroller = Unroller(['u3', 'cx'])
uqc = dag_to_circuit(unroller.run(dag))
print(uqc.size())
self.log.info('%s gate count: %d', uqc.name, uqc.size())
self.assertTrue(uqc.size() <= 93) # this limit could be changed
def layer_parser(circ, two_qubit_gate='cx', coupling_map=None):
"""
Tranforms general circuits into a nice form for a qotp.
Args:
circ (QuantumCircuit): A generic quantum circuit
two_qubit_gate (str): a flag as to which 2 qubit
gate to compile with, can be cx or cz
coupling_map (list): some particular device topology as list
of list (e.g. [[0,1],[1,2],[2,0]])
Returns:
dict: A dictionary of the parsed layers with the following keys:
``singlequbit_layers`` (lsit): a list of circuits describing
the single qubit gates
``cz_layers`` (list): a list of circuits describing the cz layers
``meas_layer`` (QuantumCircuit): a circuit describing the final measurement
Raises:
QiskitError: If a circuit element is not implemented in qotp
"""
# transpile to single qubits and cx
# TODO: replace cx with cz when that is available
circ_internal = transpile(circ,
optimization_level=2,
basis_gates=['u1', 'u2', 'u3', 'cx'],
coupling_map=coupling_map)
# quantum and classial registers
qregs = circ_internal.qregs[0]
cregs = circ_internal.cregs[0]
# conatiners for the eventual output passed to the accred code
singlequbitlayers = [
QuantumCircuit(qregs, cregs),
QuantumCircuit(qregs, cregs)
]
twoqubitlayers = [QuantumCircuit(qregs, cregs)]
measlayer = QuantumCircuit(qregs, cregs)
# some flags for simplicity
current2qs = []
# loop through circuit (best to use the dag object)
dag_internal = circuit_to_dag(circ_internal)
for dag_layer in dag_internal.layers():
circuit_layer = dag_to_circuit(dag_layer['graph'])
for circelem, qsub, csub in circuit_layer:
n = circelem.name
if n == "barrier":
# if a barrier separates any two qubit gates
# start a new layer
if current2qs != []:
singlequbitlayers.append(QuantumCircuit(qregs, cregs))
twoqubitlayers.append(QuantumCircuit(qregs, cregs))
current2qs = []
singlequbitlayers[-2].append(circelem, qsub, csub)
elif n in ('u1', 'u2', 'u3'):
# single qubit gate
q = qsub[0]
if q in current2qs:
singlequbitlayers[-1].append(circelem, qsub, csub)
else:
singlequbitlayers[-2].append(circelem, qsub, csub)
elif n == "cx":
# cx indices
q_0 = qsub[0]
q_1 = qsub[1]
# check if new cnot satisfies overlap criteria
if q_0 in current2qs or q_1 in current2qs:
singlequbitlayers.append(QuantumCircuit(qregs, cregs))
twoqubitlayers.append(QuantumCircuit(qregs, cregs))
current2qs = []
if two_qubit_gate == 'cx':
# append cx
twoqubitlayers[-1].cx(q_0, q_1)
elif two_qubit_gate == 'cz':
# append and correct to cz with h gates
twoqubitlayers[-1].cz(q_0, q_1)
singlequbitlayers[-1].h(qsub[1])
singlequbitlayers[-2].h(qsub[1])
else:
raise QiskitError(
"Two qubit gate {0}".format(two_qubit_gate) +
" is not implemented in qotp")
# add to current
current2qs.append(q_0)
current2qs.append(q_1)
elif n == "measure":
measlayer.append(circelem, qsub, csub)
else:
raise QiskitError("Circuit element {0}".format(n) +
" is not implemented in qotp")
if current2qs == []:
del singlequbitlayers[-1]
del twoqubitlayers[-1]
for ind, circlayer in enumerate(singlequbitlayers):
singlequbitlayers[ind] = transpile(circlayer,
basis_gates=['u1', 'u2', 'u3'])
parsedlayers = {
'singlequbitlayers': singlequbitlayers,
'twoqubitlayers': twoqubitlayers,
'measlayer': measlayer,
'twoqubitgate': two_qubit_gate,
'qregs': qregs,
'cregs': cregs
}
return parsedlayers
n_qubits = int(math.log(dim, 2))
converter.n_qubits = n_qubits
n_cnots = (n_layers // 2) * (n_qubits // 2) + ((n_qubits - 1) // 2) * (
(n_layers + 1) // 2)
r = RewriteTket(Circuit(n_qubits), [], [])
r.set_target_unitary(unitary)
skips = []
circuit, distance = approximate_scipy(unitary, n_layers, r, [])
for k in range(10):
new_skip = random.choice([i for i in range(n_cnots) if i not in skips])
print("maybe I will skip", new_skip)
new_circ, new_d = approximate_scipy(unitary, n_layers, r,
skips + [new_skip])
if new_d <= distance: # or random.random() < (1 - new_d + distance) / (5 * k + 1):
print("skipping", new_skip)
circuit, distance, skips = new_circ, new_d, skips + [new_skip]
else:
print("not skipping", new_skip)
print(circuit.n_gates, circuit.n_gates_of_type(OpType.CX))
if distance < 0.01:
print("returning early", distance)
return circuit, r.fidelity(circuit)
print(distance)
return circuit, r.fidelity(circuit)
circuit, fid = approximate_scipy(unitary, n_layers, r)
print("final fidelity", fid)
print(circuit.n_gates, circuit.n_gates_of_type(OpType.CX))
print(dag_to_circuit(tk_to_dagcircuit(circuit)))
def run(self, dag):
"""Run the Unroller pass on `dag`.
Args:
dag (DAGCircuit): input dag
Raises:
QiskitError: if unable to unroll given the basis due to undefined
decomposition rules (such as a bad basis) or excessive recursion.
Returns:
DAGCircuit: output unrolled dag
"""
if self.basis is None:
return dag
# Walk through the DAG and expand each non-basis node
basic_insts = ["measure", "reset", "barrier", "snapshot", "delay"]
for node in dag.op_nodes():
if getattr(node.op, "_directive", False):
continue
if node.name in basic_insts:
# TODO: this is legacy behavior.Basis_insts should be removed that these
# instructions should be part of the device-reported basis. Currently, no
# backend reports "measure", for example.
continue
if node.name in self.basis: # If already a base, ignore.
if isinstance(node.op, ControlledGate) and node.op._open_ctrl:
pass
else:
continue
if isinstance(node.op, ControlFlowOp):
unrolled_blocks = []
for block in node.op.blocks:
dag_block = circuit_to_dag(block)
unrolled_dag_block = self.run(dag_block)
unrolled_circ_block = dag_to_circuit(unrolled_dag_block)
unrolled_blocks.append(unrolled_circ_block)
node.op = node.op.replace_blocks(unrolled_blocks)
continue
try:
phase = node.op.definition.global_phase
rule = node.op.definition.data
except (TypeError, AttributeError) as err:
raise QiskitError(
f"Error decomposing node of instruction '{node.name}': {err}. "
f"Unable to define instruction '{node.name}' in the given basis."
) from err
# Isometry gates definitions can have widths smaller than that of the
# original gate, in which case substitute_node will raise. Fall back
# to substitute_node_with_dag if an the width of the definition is
# different that the width of the node.
while rule and len(rule) == 1 and len(node.qargs) == len(
rule[0].qubits) == 1:
if rule[0].operation.name in self.basis:
dag.global_phase += phase
dag.substitute_node(node, rule[0].operation, inplace=True)
break
try:
phase += rule[0].operation.definition.global_phase
rule = rule[0].operation.definition.data
except (TypeError, AttributeError) as err:
raise QiskitError(
f"Error decomposing node of instruction '{node.name}': {err}. "
f"Unable to define instruction '{rule[0].operation.name}' in the basis."
) from err
else:
if not rule:
if rule == []: # empty node
dag.remove_op_node(node)
dag.global_phase += phase
continue
# opaque node
raise QiskitError(
"Cannot unroll the circuit to the given basis, %s. "
"No rule to expand instruction %s." %
(str(self.basis), node.op.name))
decomposition = circuit_to_dag(node.op.definition)
unrolled_dag = self.run(
decomposition) # recursively unroll ops
dag.substitute_node_with_dag(node, unrolled_dag)
return dag
def ha_mapping(
quantum_circuit: QuantumCircuit,
initial_mapping: ty.Dict[Qubit, int],
hardware: IBMQHardwareArchitecture,
swap_cost_heuristic: ty.Callable[
[
IBMQHardwareArchitecture, # Hardware information
QuantumLayer, # Current front layer
ty.List[DAGNode], # Topologically sorted list of nodes
int, # Index of the first non-processed gate.
ty.Dict[Qubit, int], # The mapping before applying the tested SWAP/Bridge
ty.Dict[Qubit, int], # The initial mapping
ty.Dict[Qubit, int], # The trans mapping
numpy.ndarray, # The distance matrix between each qubits
TwoQubitGate, # The SWAP/Bridge we want to rank
],
float,
] = sabre_heuristic,
get_candidates: ty.Callable[
[QuantumLayer, IBMQHardwareArchitecture, ty.Dict[Qubit, int], ty.Dict[Qubit, int], ty.Dict[Qubit, int], ty.Set[str],],
ty.List[TwoQubitGate],
] = get_all_swap_bridge_candidates,
get_distance_matrix: ty.Callable[
[IBMQHardwareArchitecture], numpy.ndarray
] = get_distance_matrix_swap_number_and_error,
) -> ty.Tuple[QuantumCircuit, ty.Dict[Qubit, int]]:
"""Map the given quantum circuit to the hardware topology provided.
:param quantum_circuit: the quantum circuit to map.
:param initial_mapping: the initial mapping used to start the iterative mapping
algorithm.
:param hardware: hardware data such as connectivity, gate time, gate errors, ...
:param swap_cost_heuristic: the heuristic cost function that will estimate the cost
of a given SWAP/Bridge according to the current state of the circuit.
:param get_candidates: a function that takes as input the current front
layer and the hardware description and that returns a list of tuples
representing the SWAP/Bridge that should be considered by the heuristic.
:param get_distance_matrix: a function that takes as first (and only) parameter the
hardware representation and that outputs a numpy array containing the cost of
performing a SWAP between each pair of qubits.
:return: The final circuit along with the mapping obtained at the end of the
iterative procedure.
"""
_adapt_quantum_circuit_and_mapping_arity(quantum_circuit, initial_mapping, hardware)
# Creating the internal data structures that will be used in this function.
dag_circuit = circuit_to_dag(quantum_circuit)
distance_matrix = get_distance_matrix(hardware)
resulting_dag_quantum_circuit = _create_empty_dagcircuit_from_existing(dag_circuit)
current_mapping = initial_mapping
explored_mappings: ty.Set[str] = set()
# Sorting all the quantum operations in topological order once for all.
# May require significant memory on large circuits...
topological_nodes: ty.List[DAGNode] = list(dag_circuit.topological_op_nodes())
current_node_index = 0
# Creating the initial front layer.
front_layer = QuantumLayer()
current_node_index = update_layer(
front_layer, topological_nodes, current_node_index
)
trans_mapping = initial_mapping.copy()
# Start of the iterative algorithm
while not front_layer.is_empty():
execute_gate_list = QuantumLayer()
for op in front_layer.ops:
if hardware.can_natively_execute_operation(op, current_mapping):
execute_gate_list.add_operation(op)
# Delaying the remove operation because we do not want to remove from
# a container we are iterating on.
# front_layer.remove_operation(op)
if not execute_gate_list.is_empty():
front_layer.remove_operations_from_layer(execute_gate_list)
execute_gate_list.apply_back_to_dag_circuit(
resulting_dag_quantum_circuit, initial_mapping, trans_mapping
)
# Empty the explored mappings because at least one gate has been executed.
explored_mappings.clear()
else:
inverse_mapping = {val: key for key, val in initial_mapping.items()}
# We cannot execute any gate, that means that we should insert at least
# one SWAP/Bridge to make some gates executable.
# First list all the SWAPs/Bridges that may help us make some gates
# executable.
swap_candidates = get_candidates(
front_layer, hardware, initial_mapping, current_mapping, trans_mapping, explored_mappings
)
# Then rank the SWAPs/Bridge and take the best one.
best_swap_qubits = None
best_cost = float("inf")
for potential_swap in swap_candidates:
cost = swap_cost_heuristic(
hardware,
front_layer,
topological_nodes,
current_node_index,
current_mapping,
initial_mapping,
trans_mapping,
distance_matrix,
potential_swap,
)
if cost < best_cost:
best_cost = cost
best_swap_qubits = potential_swap
# We now have our best SWAP/Bridge, let's perform it!
current_mapping = best_swap_qubits.update_mapping(current_mapping)
if isinstance(best_swap_qubits, SwapTwoQubitGate):
control, target = current_mapping[best_swap_qubits.left], current_mapping[best_swap_qubits.right]
swap_control, swap_target = inverse_mapping[control], inverse_mapping[target]
best_swap_qubits = SwapTwoQubitGate(
swap_control, swap_target
)
#print("swap gates is :", best_swap_qubits.left, best_swap_qubits.right)
trans_mapping[best_swap_qubits.left], trans_mapping[best_swap_qubits.right] = (
trans_mapping[best_swap_qubits.right],
trans_mapping[best_swap_qubits.left],
)
else:
#print("brige gate is :", best_swap_qubits.left, best_swap_qubits.middle, best_swap_qubits.right)
pass
explored_mappings.add(mapping_to_str(current_mapping))
best_swap_qubits.apply(resulting_dag_quantum_circuit, front_layer, initial_mapping, trans_mapping)
# Anyway, update the current front_layer
current_node_index = update_layer(
front_layer, topological_nodes, current_node_index
)
# We are done here, we just need to return the results
# resulting_dag_quantum_circuit.draw(scale=1, filename="qcirc.dot")
resulting_circuit = dag_to_circuit(resulting_dag_quantum_circuit)
return resulting_circuit, current_mapping
def ha_mapping_paper_compliant(
quantum_circuit: QuantumCircuit,
initial_mapping: ty.Dict[Qubit, int],
hardware: IBMQHardwareArchitecture,
swap_cost_and_effect_heuristic: ty.Callable[
[
IBMQHardwareArchitecture, # Hardware information
QuantumLayer, # Current front layer
ty.List[DAGNode], # Topologically sorted list of nodes
int, # Index of the first non-processed gate.
ty.Dict[Qubit, int], # The mapping before applying the tested SWAP/Bridge
ty.Dict[Qubit, int], # The initial mapping
ty.Dict[Qubit, int], # The trans mapping
numpy.ndarray, # The distance matrix between each qubits
TwoQubitGate, # The SWAP/Bridge we want to rank
],
ty.Tuple[
float, # Cost of the SWAP pair
float, # Effect of the SWAP pair on the other gates
],
] = sabre_heuristic_with_effect,
get_candidates: ty.Callable[
[QuantumLayer, IBMQHardwareArchitecture, ty.Dict[Qubit, int], ty.Set[str],],
ty.List[SwapTwoQubitGate],
] = get_all_swap_candidates,
get_distance_matrix: ty.Callable[
[IBMQHardwareArchitecture], numpy.ndarray
] = get_distance_matrix_swap_number_and_error,
) -> ty.Tuple[QuantumCircuit, ty.Dict[Qubit, int]]:
"""Map the given quantum circuit to the hardware topology provided.
This implementation uses the exact same algorithm described in the associated
scientific paper. Another implementation using a different method to choose
between SWAP and Bridge is available as `:py:func:`~hamap.mapping.ha_mapping`.
:param quantum_circuit: the quantum circuit to map.
:param initial_mapping: the initial mapping used to start the iterative mapping
algorithm.
:param hardware: hardware data such as connectivity, gate time, gate errors, ...
:param swap_cost_and_effect_heuristic: the heuristic cost function that will
estimate the cost of a given SWAP according to the current state of the circuit
and the effect of the SWAP on the following quantum gates. The two floats
should be returned as a tuple (cost, effect).
:param get_candidates: a function that takes as input the current front
layer and the hardware description and that returns a list of tuples
representing the SWAP that should be considered by the heuristic.
:param get_distance_matrix: a function that takes as first (and only) parameter the
hardware representation and that outputs a numpy array containing the cost of
performing a SWAP between each pair of qubits.
:return: The final circuit along with the mapping obtained at the end of the
iterative procedure.
"""
_adapt_quantum_circuit_and_mapping_arity(quantum_circuit, initial_mapping, hardware)
# Creating the internal data structures that will be used in this function.
dag_circuit = circuit_to_dag(quantum_circuit)
distance_matrix = get_distance_matrix(hardware)
resulting_dag_quantum_circuit = _create_empty_dagcircuit_from_existing(dag_circuit)
current_mapping = initial_mapping
explored_mappings: ty.Set[str] = set()
# Sorting all the quantum operations in topological order once for all.
# May require significant memory on large circuits...
topological_nodes: ty.List[DAGNode] = list(dag_circuit.topological_op_nodes())
current_node_index = 0
# Creating the initial front layer.
front_layer = QuantumLayer()
current_node_index = update_layer(
front_layer, topological_nodes, current_node_index
)
swap_distance_matrix = get_distance_matrix_swap_number(hardware)
trans_mapping = initial_mapping.copy()
# Start of the iterative algorithm
while not front_layer.is_empty():
execute_gate_list = QuantumLayer()
for op in front_layer.ops:
if hardware.can_natively_execute_operation(op, current_mapping):
execute_gate_list.add_operation(op)
# Delaying the remove operation because we do not want to remove from
# a container we are iterating on.
# front_layer.remove_operation(op)
if not execute_gate_list.is_empty():
front_layer.remove_operations_from_layer(execute_gate_list)
execute_gate_list.apply_back_to_dag_circuit(
resulting_dag_quantum_circuit, initial_mapping, trans_mapping
)
# Empty the explored mappings because at least one gate has been executed.
explored_mappings.clear()
else:
# We cannot execute any gate, that means that we should insert at least
# one SWAP/Bridge to make some gates executable.
# First list all the SWAPs/Bridges that may help us make some gates
# executable.
inverse_mapping = {val: key for key, val in initial_mapping.items()}
swap_candidates = get_candidates(
front_layer, hardware, current_mapping, explored_mappings
)
# Then rank the SWAPs/Bridge and take the best one.
best_swap_qubits = None
best_cost = float("inf")
best_effect = 0.0
for potential_swap in swap_candidates:
cost, swap_effect = swap_cost_and_effect_heuristic(
hardware,
front_layer,
topological_nodes,
current_node_index,
current_mapping,
initial_mapping,
trans_mapping,
distance_matrix,
potential_swap,
)
if cost < best_cost:
best_cost = cost
best_effect = swap_effect
best_swap_qubits = potential_swap
# We now have our best SWAP, let's check if a Bridge is not better
# if (
# best_effect < 0
# and swap_distance_matrix[best_swap_qubits.left][best_swap_qubits.right]
# == 2
# ):
# i, j = best_swap_qubits
# common_neighbours = set(hardware.neighbors(i)) & set(
# hardware.neighbors(j)
# )
# if len(common_neighbours) < 1:
# raise RuntimeError("Less than one common neighbour")
# common_neighbour = list(common_neighbours)[0]
# best_gate = BridgeTwoQubitGate(i, common_neighbour, j)
if best_effect < 0:
inverse_trans_mapping = {val: key for key, val in trans_mapping.items()}
for op in front_layer.ops:
if len(op.qargs) < 2:
# We just pass 1 qubit gates because they do not participate in the
# Bridge operation
continue
if len(op.qargs) != 2:
logger.warning("A 3-qubit or more gate has been found in the circuit.")
continue
control, target = op.qargs
control_index = initial_mapping[inverse_trans_mapping[initial_mapping[control]]]
target_index = initial_mapping[inverse_trans_mapping[initial_mapping[target]]]
for _, potential_middle_index in hardware.out_edges(control_index):
for _, potential_target_index in hardware.out_edges(potential_middle_index):
if potential_target_index == target_index:
best_swap_qubits = BridgeTwoQubitGate(
inverse_trans_mapping[initial_mapping[control]],
inverse_mapping[potential_middle_index],
inverse_trans_mapping[initial_mapping[target]],
)
current_mapping = best_swap_qubits.update_mapping(current_mapping)
if isinstance(best_swap_qubits, SwapTwoQubitGate):
control, target = current_mapping[best_swap_qubits.left], current_mapping[best_swap_qubits.right]
swap_control, swap_target = inverse_mapping[control], inverse_mapping[target]
best_swap_qubits = SwapTwoQubitGate(
swap_control, swap_target
)
#print("swap gates is :", best_swap_qubits.left, best_swap_qubits.right)
trans_mapping[best_swap_qubits.left], trans_mapping[best_swap_qubits.right] = (
trans_mapping[best_swap_qubits.right],
trans_mapping[best_swap_qubits.left],
)
else:
#print("brige gate is :", best_swap_qubits.left, best_swap_qubits.middle, best_swap_qubits.right)
pass
explored_mappings.add(mapping_to_str(current_mapping))
best_swap_qubits.apply(resulting_dag_quantum_circuit, front_layer, initial_mapping, trans_mapping)
# Anyway, update the current front_layer
current_node_index = update_layer(
front_layer, topological_nodes, current_node_index
)
# We are done here, we just need to return the results
# resulting_dag_quantum_circuit.draw(scale=1, filename="qcirc.dot")
resulting_circuit = dag_to_circuit(resulting_dag_quantum_circuit)
return resulting_circuit, current_mapping
