def run_dag_opt(self):
"""
It runs the substitution algorithm and creates the optimized DAGCircuit().
"""
self._substitution()
dag_dep_opt = DAGDependency()
dag_dep_opt.name = self.circuit_dag_dep.name
qregs = list(self.circuit_dag_dep.qregs.values())
cregs = list(self.circuit_dag_dep.cregs.values())
for register in qregs:
dag_dep_opt.add_qreg(register)
for register in cregs:
dag_dep_opt.add_creg(register)
already_sub = []
if self.substitution_list:
# Loop over the different matches.
for group in self.substitution_list:
circuit_sub = group.circuit_config
template_inverse = group.template_config
pred = group.pred_block
qubit = group.qubit_config[0]
if group.clbit_config:
clbit = group.clbit_config[0]
else:
clbit = []
# First add all the predecessors of the given match.
for elem in pred:
node = self.circuit_dag_dep.get_node(elem)
inst = node.op.copy()
inst.condition = node.condition
dag_dep_opt.add_op_node(inst, node.qargs, node.cargs)
already_sub.append(elem)
already_sub = already_sub + circuit_sub
# Then add the inverse of the template.
for index in template_inverse:
all_qubits = self.circuit_dag_dep.qubits
qarg_t = group.template_dag_dep.get_node(index).qindices
qarg_c = [qubit[x] for x in qarg_t]
qargs = [all_qubits[x] for x in qarg_c]
all_clbits = self.circuit_dag_dep.clbits
carg_t = group.template_dag_dep.get_node(index).cindices
if all_clbits and clbit:
carg_c = [clbit[x] for x in carg_t]
cargs = [all_clbits[x] for x in carg_c]
else:
cargs = []
node = group.template_dag_dep.get_node(index)
inst = node.op.copy()
inst.condition = node.condition
dag_dep_opt.add_op_node(inst.inverse(), qargs, cargs)
# Add the unmatched gates.
for node_id in self.unmatched_list:
node = self.circuit_dag_dep.get_node(node_id)
inst = node.op.copy()
inst.condition = node.condition
dag_dep_opt.add_op_node(inst, node.qargs, node.cargs)
dag_dep_opt._add_successors()
# If there is no valid match, it returns the original dag.
else:
dag_dep_opt = self.circuit_dag_dep
self.dag_dep_optimized = dag_dep_opt
self.dag_optimized = dagdependency_to_dag(dag_dep_opt)
def run(self, dag):
"""
Args:
dag(DAGCircuit): DAG circuit.
Returns:
DAGCircuit: optimized DAG circuit.
Raises:
TranspilerError: If the template has not the right form or
if the output circuit acts differently as the input circuit.
"""
circuit_dag = dag
circuit_dag_dep = dag_to_dagdependency(circuit_dag)
circuit = dagdependency_to_circuit(circuit_dag_dep)
operator_ini = Operator(circuit)
for template in self.template_list:
if not isinstance(template, QuantumCircuit):
raise TranspilerError('A template is a Quantumciruit().')
identity = np.identity(2**template.num_qubits, dtype=complex)
comparison = np.allclose(Operator(template).data, identity)
if not comparison:
raise TranspilerError(
'A template is a Quantumciruit() that performs the identity.'
)
if template.num_qubits > len(circuit_dag_dep.qubits):
raise TranspilerError(
'A template should have equal or less number of qubit'
' compared to the circuit.')
template_dag_dep = circuit_to_dagdependency(template)
template_m = TemplateMatching(circuit_dag_dep, template_dag_dep,
self.heuristics_qubits_param,
self.heuristics_backward_param)
template_m.run_template_matching()
matches = template_m.match_list
if matches:
maximal = MaximalMatches(matches)
maximal.run_maximal_matches()
max_matches = maximal.max_match_list
substitution = TemplateSubstitution(
max_matches, template_m.circuit_dag_dep,
template_m.template_dag_dep)
substitution.run_dag_opt()
circuit_dag_dep = substitution.dag_dep_optimized
circuit_intermediate = dagdependency_to_circuit(
circuit_dag_dep)
opertator_intermediate = Operator(circuit_intermediate)
if operator_ini != opertator_intermediate:
raise TranspilerError(
'A failure happened during the substitution.')
else:
continue
circuit_dag = dagdependency_to_dag(circuit_dag_dep)
return circuit_dag