In Qiskit, they have the concept of a Toffoli gate (
ccx). However, the following code throws an error:
from qiskit import QuantumCircuit, ClassicalRegister, QuantumRegister from qiskit import execute, Aer q1 = QuantumRegister(2) qctrl = QuantumRegister(1) c = ClassicalRegister(2) qc = QuantumCircuit(q1, qctrl, c) qc.x(q1) qc.ccx(q1, q1, qctrl) qc.measure(q1, c) backend_sim = Aer.get_backend('qasm_simulator') job_sim = execute(qc, backend_sim) result_sim = job_sim.result() print(result_sim.get_counts(qc))
According to my knowledge and research, this should produce the output
111 but instead I get an error message:
qiskit.qiskiterror.QiskitError: "QuantumRegister(1, 'q0') is not a tuple. A qubit should be formated as a tuple."
This seems like a bug with Qiskit to me. Am I wrong? And if so, how can I fix my code?