Source code for qolumbina.programs.parity.parity_qubit

# This code is developed through cross-language conversion from 
# https://github.com/MgcosA/Code_of_Testing_Oracle_Quantum_Program_Article/blob/master/qolumbina/programs/Parity.qs
# 
# In detail, the raw program is written in Q#, and we rewrite it in Qiskit.

from qiskit import QuantumCircuit, QuantumRegister


# ---------- benchmark registration ----------
from ..benchmark_registry import register_benchmark
from pathlib import Path
@register_benchmark(
    Path(__file__).stem,
    family=Path(__file__).resolve().parent.name,
    description="Parity oracle (qubit version)",
    class_name="ParityQubit",
    source={
        "repo": "https://github.com/MgcosA/Code_of_Testing_Oracle_Quantum_Program_Article/blob/master/",
        "file": "qolumbina/programs/Parity.qs",
        "sdk": "Q#",
        "available_doc": True
    },
    testability_refactoring=[
        "Cross-language translation", 
        "Structure reorganization"
    ] 
)
def create_parity_qubit(input_qubits):
    return ParityQubit(input_qubits=input_qubits)   



class ParityQubit(QuantumCircuit):
    r"""
    Qubit version of the parity oracle.
    """
    def __init__(self, input_qubits: int, name: str | None = None):
        r"""
        Args:
            input_qubits: Number of input qubits :math:`n`.
            name: Optional name of the circuit.
        """

        # ---------- registers ----------
        q_input = QuantumRegister(input_qubits, "q")
        q_target = QuantumRegister(1, "target")

        super().__init__(q_input, q_target, name=name or "ParityQubit")
        self._input_qubits = input_qubits
        self._build()

    def _build(self):
        qs = self.qregs[0]
        qtarget = self.qregs[1][0]

        for q in qs:
            # Correpsond to CNOT(qs[i], qtarget)
            self.cx(q, qtarget)