Source code for qiskit_nature.second_q.drivers.gaussiand.gaussian_log_driver

# This code is part of a Qiskit project.
#
# (C) Copyright IBM 2020, 2023.
#
# This code is licensed under the Apache License, Version 2.0. You may
# obtain a copy of this license in the LICENSE.txt file in the root directory
# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
#
# Any modifications or derivative works of this code must retain this
# copyright notice, and modified files need to carry a notice indicating
# that they have been altered from the originals.

""" Gaussian Log Driver """

from __future__ import annotations

from typing import Union
import logging

from qiskit_nature import QiskitNatureError
import qiskit_nature.optionals as _optionals

from ..base_driver import BaseDriver
from .gaussian_utils import run_g16
from .gaussian_log_result import GaussianLogResult

logger = logging.getLogger(__name__)


@_optionals.HAS_GAUSSIAN.require_in_instance
class GaussianLogDriver(BaseDriver):
    """Gaussian™ 16 log driver.

    Qiskit Nature driver using the Gaussian™ 16 program that provides the log
    back, via :class:`GaussianLogResult`, for access to the log and data recorded there.

    See http://gaussian.com/gaussian16/

    This driver does not use Gaussian 16 interfacing code, as certain data such as forces
    properties are not present in the MatrixElement file. The log is returned as a
    :class:`GaussianLogResult` allowing it to be parsed for whatever data may be of interest.
    This result class also contains ready access to certain data within the log.
    """

    def __init__(self, jcf: Union[str, list[str]]) -> None:
        r"""
        Args:
            jcf: A job control file conforming to Gaussian™ 16 format. This can
                be provided as a single string with '\\n' line separators or as a list of
                strings.
        Raises:
            QiskitNatureError: Invalid Input
        """
        if not isinstance(jcf, list) and not isinstance(jcf, str):
            raise QiskitNatureError(f"Invalid input for Gaussian Log Driver '{jcf}'")

        if isinstance(jcf, list):
            jcf = "\n".join(jcf)

        self._jcf = jcf
        super().__init__()

    def run(self) -> GaussianLogResult:  # type: ignore[override]
        """Runs the driver to produce a result given the supplied job control file.

        Returns:
            A log file result.

        Raises:
            QiskitNatureError: Missing output log
        """
        # The job control file, needs to end with a blank line to be valid for
        # Gaussian to process it. We simply add the blank line here if not.
        cfg = self._jcf
        while not cfg.endswith("\n\n"):
            cfg += "\n"

        logger.debug(
            "User supplied job control file raw: '%s'",
            cfg.replace("\r", "\\r").replace("\n", "\\n"),
        )
        logger.debug("User supplied job control file\n%s", cfg)

        all_text = run_g16(cfg)
        if not all_text:
            raise QiskitNatureError("Failed to capture log from stdout")

        return GaussianLogResult(all_text)