ParityQC の「Parity Twine Optimizer」で、市場の分断問題を解決しましょう

import tempfile

from collections.abc import Callable
from pathlib import Path

import numpy as np
import requests

from qiskit_addon_opt_mapper import OptimizationProblem
from qiskit_addon_opt_mapper.converters import OptimizationProblemToQubo
from qiskit_ibm_catalog import QiskitFunctionsCatalog

catalog = QiskitFunctionsCatalog(channel="ibm_quantum_platform")
function = catalog.load("parityqc/parity-twine-optimizer")

def load_market_split_problem(instance_name: str) -> OptimizationProblem:
    """Load and formulate a market split optimization problem from an QOBLIB instance.

    The QOBLIB library can be found here:
    https://github.com/ZIB-AOPT/QOBLIB.

    Args:
        instance_name: Name of the market split instance to load as specified by the .dat file
            in the QOBLIB repo.

    Returns:
        The output OptimizationProblem containing the loaded market split problem.
    """

    problem_matrix, problem_vector = fetch_and_parse(
        instance_name, "01-marketsplit", parse_marketsplit_dat
    )

    # Create optimization problem
    optimization_problem = OptimizationProblem(instance_name)

    # Add binary variables (one for each market)
    optimization_problem.binary_var_list(problem_matrix.shape[1])

    # Add equality constraints (one for each product)
    for idx, rhs in enumerate(problem_vector):
        optimization_problem.linear_constraint(
            problem_matrix[idx, :], sense="==", rhs=rhs
        )

    # Convert to QUBO with penalty parameter
    return OptimizationProblemToQubo(penalty=1).convert(optimization_problem)

def fetch_and_parse(instance_name: str, problem: str, parse_func: Callable):
    """Generic function to fetch and parse data from QOBLIB repository.

    Args:
        instance_name: Name of the instance to fetch.
        problem: Category of the problem (e.g., '01-marketsplit', '07-independentset').
        parse_func: Function used to parse the downloaded file
            (e.g., parse_marketsplit_dat, parse_gph_file).

    Returns:
        Result of `parse_func` - either (np.ndarray, np.ndarray) for marketsplit
        or nx.Graph for MIS.
    """
    base_url = (
        "https://raw.githubusercontent.com/ZIB-AOPT/QOBLIB/refs/heads/main/"
    )
    url = (
        base_url
        + problem
        + "/instances/"
        + instance_name
        + (".dat" if problem == "01-marketsplit" else ".gph")
    )

    try:
        response = requests.get(url, timeout=30)
        response.raise_for_status()

        with tempfile.NamedTemporaryFile(
            mode="w",
            suffix=".dat" if problem == "01-marketsplit" else ".gph",
            delete=False,
            encoding="utf-8",
        ) as temp_file:
            temp_file.write(response.text)
            temp_file_path = temp_file.name

        try:
            return parse_func(temp_file_path)
        finally:
            Path(temp_file_path).unlink(missing_ok=True)

    except requests.RequestException as e:
        print(f"Error fetching data from repository: {e}")
    except (ValueError, OSError) as e:
        print(f"Error processing data: {e}")
        return None


def parse_marketsplit_dat(filename: str) -> tuple[np.ndarray, np.ndarray]:
    """Parse a market split problem from a .dat file format.

    Args:
        filename: Path to the .dat file.

    Returns:
        Tuple of (A, b) where:
            - A: (m, n) array of coefficients.
            - b: (m,) array of target values.

    Raises:
        ValueError: If file format is invalid or file is empty.
    """
    with Path(filename).open(encoding="utf-8") as f:
        lines = [
            line.strip()
            for line in f
            if line.strip() and not line.startswith("#")
        ]

    if not lines:
        raise ValueError("Empty or invalid .dat file")

    # First line: m n (number of products and markets)
    try:
        m, n = map(int, lines[0].split())
    except (ValueError, IndexError) as e:
        raise ValueError(
            "Invalid file format: first line must contain 'm n' integers"
        ) from e

    if len(lines) < m + 1:
        raise ValueError(
            f"File contains {len(lines)} lines but expected {m + 1} lines"
        )

    # Next m lines: each row of A followed by corresponding element of b
    mat_a = []
    vec_b = []

    for i in range(1, m + 1):
        try:
            values = list(map(int, lines[i].split()))
        except ValueError as e:
            raise ValueError(f"Invalid integer values in line {i + 1}") from e

        if len(values) != n + 1:
            raise ValueError(
                f"Line {i + 1} contains {len(values)} values but expected {n + 1}"
            )

        mat_a.append(values[:-1])  # First n values: product sales per market
        vec_b.append(values[-1])  # Last value: target sales for this product

    return np.array(mat_a), np.array(vec_b)

ms_instance = "ms_04_050_001"

ms_problem = load_market_split_problem(ms_instance)

def optimization_problem_to_json(
    problem: OptimizationProblem,
) -> dict[str, float]:
    """
    Converts an unconstrained quadratic OptimizationProblem in terms of binary or spin variables
    to the JSON input format of the Parity Twine Qiskit Function.

    Args:
        problem: The optimization problem to convert to JSON.

    Returns:
        The JSON input format of the given problem.
    """
    ising, constant = problem.to_ising()
    output = {"()": float(constant)}
    for op, coefficient in zip(ising.paulis, ising.coeffs, strict=True):
        # Invert the label strings because Qiskit has opposite convention
        qubits = tuple(
            num
            for num, pauli in enumerate(op.to_label()[::-1])
            if pauli == "Z"
        )
        output[str(qubits)] = float(coefficient)
    return output

json_ms_problem = optimization_problem_to_json(ms_problem)

options = {
    "shots": 100000,
    "postprocessing_level": 1,
    "transpile_only": False,
    "job_tags": ["market_split"],
}

function_job = function.run(
    problem=json_ms_problem,
    variable_type="spin",
    backend_name="ibm_phoenix",
    options=options,
)
print(f"Job ID: {function_job.job_id}")

# Monitor the job status
function_job.status()

# Retrieve the job result if the status is DONE
result = function_job.result()

result