dag_to_circuit¶

dag_to_circuit(dag)[source]¶

Build a QuantumCircuit object from a DAGCircuit.

Parameters: dag (DAGCircuit) – the input dag.
Returns: the circuit representing the input dag.
Return type: QuantumCircuit

Example

from qiskit import QuantumRegister, ClassicalRegister, QuantumCircuit
from qiskit.dagcircuit import DAGCircuit
from qiskit.converters import circuit_to_dag
from qiskit.circuit.library.standard_gates import CHGate, U2Gate, CXGate
from qiskit.converters import dag_to_circuit
%matplotlib inline

q = QuantumRegister(3, 'q')
c = ClassicalRegister(3, 'c')
circ = QuantumCircuit(q, c)
circ.h(q[0])
circ.cx(q[0], q[1])
circ.measure(q[0], c[0])
circ.rz(0.5, q[1]).c_if(c, 2)
dag = circuit_to_dag(circ)
circuit = dag_to_circuit(dag)
circuit.draw()

     ┌───┐     ┌─┐           
q_0: ┤ H ├──■──┤M├───────────
     └───┘┌─┴─┐└╥┘┌─────────┐
q_1: ─────┤ X ├─╫─┤ RZ(0.5) ├
          └───┘ ║ └────┬────┘
q_2: ───────────╫──────┼─────
                ║   ┌──┴──┐  
c_0: ═══════════╩═══╡     ╞══
                    │     │  
c_1: ═══════════════╡ = 2 ╞══
                    │     │  
c_2: ═══════════════╡     ╞══
                    └─────┘