Source code for pynegf

import ctypes
import ctypes.util
import logging
import typing

# Package imports.
from .pynegf import PyNegf


class Settings(dict):
    """
    A global setting dictionary.
    """
    def __init__(self) -> None:
        """
        Construct the settings dictionary.
        """
        # Populate first with all defaults.
        self.update(self.defaults())

    @staticmethod
    def defaults() -> typing.Dict[str, typing.Any]:
        """
        Returns a dictionary of default settings. The available settings are:

        `negf_path`: path of libnegf
        `blas_path`: path of libblas
        `lapack_path`: path of liblapack
        """
        defaults = {}
        # Populate the default paths.
        for lib in ('negf', 'blas', 'lapack'):
            defaults[lib + '_path'] = ctypes.util.find_library(lib)

        return defaults


# Initialize global settings.
settings = Settings()

# Set log level temporarily hardcoded.
logging.getLogger().setLevel(logging.INFO)


def load_dependencies() -> typing.Dict[str, ctypes.CDLL]:
    """
    Load at module level the ctypes dependencies.

    Returns:
        A dictionary containing the loaded library instances.
    """

    # Load libraries
    error_message = (
        "lib{0} was not found. Provide a path in pynegf.settings['{0}_path'] "
        " and run >>>pynegf.dependencies = pynegf.load_dependencies()")

    try:
        blas_cdll = ctypes.CDLL(
            settings['blas_path'],
            mode=ctypes.RTLD_GLOBAL)
    except OSError:
        blas_cdll = None
        logging.warning(error_message.format('blas'))

    try:
        lapack_cdll = ctypes.CDLL(
            settings['lapack_path'],
            mode=ctypes.RTLD_GLOBAL)
    except OSError:
        lapack_cdll = None
        logging.warning(error_message.format('lapack'))

    try:
        negf_cdll = ctypes.CDLL(settings['negf_path'])
    except OSError:
        negf_cdll = None
        logging.warning(error_message.format('negf'))

    dependencies = {
        'negf': negf_cdll,
        'blas': blas_cdll,
        'lapack': lapack_cdll}

    return dependencies


dependencies = load_dependencies()


def cdll_libnegf() -> ctypes.CDLL:
    """
    Return:
        The loaded CDLL object
    """
    return dependencies['negf']