Source code for eva.transforms.channel_stats

# (C) Copyright 2021-2022 NOAA/NWS/EMC
#
# (C) Copyright 2021-2022 United States Government as represented by the Administrator of the
# National Aeronautics and Space Administration. All Rights Reserved.
#
# This software is licensed under the terms of the Apache Licence Version 2.0
# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.


# --------------------------------------------------------------------------------------------------


from math import sqrt
import re
from statistics import mean

from eva.utilities.config import get
from eva.utilities.logger import Logger
from eva.transforms.transform_utils import parse_for_dict, split_collectiongroupvariable
from eva.transforms.transform_utils import replace_cgv
from eva.utilities.utils import remove_list_duplicates
from eva.utilities.utils import remove_empty_from_list_of_strings


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def channel_stats(config, data_collections):
    """
    Calculates statistical measures for data variables along a specified dimension.

    Args:
        config (dict): A configuration dictionary containing transformation parameters.
        data_collections (DataCollections): An instance of the DataCollections class containing
        input data.

    Returns:
        None

    This function calculates statistical measures for specified channel data variables within the
    provided data collections. It iterates over the specified collections, groups, and variables,
    and calculates statistical measures as defined in the 'statistic list' expressions within the
    configuration. The resulting variables are added to the data collections.

    Example:
        ::

                config = {
                    'collections': [...],
                    'groups': [...],
                    'variables': [...],
                    'variable_name': 'data_variable',
                    'statistic list': ['Mean', 'Std', 'Count'],
                    'statistic_dimension': 'Location'
                }
                channel_stats(config, data_collections)
    """

    # Create a logger
    logger = Logger('ChannelStatsTransform')

    # Define default stat functions to calculate
    if 'statistic list' in config:
        stat_functions = get(config, logger, 'statistic list')
    else:
        stat_functions = ['Mean', 'Std', 'Count', 'Median', 'Min', 'Max']

    # Parse the for dictionary
    [collections, groups, variables] = parse_for_dict(config, logger)

    # Parse config for the expression and new collection/group/variable naming
    variable_name_template = get(config, logger, 'variable_name')

    # Parse config for the channel dimension name
    stat_dim = get(config, logger, 'statistic_dimension', 'Location')

    # Loop over the templates
    for collection in collections:
        for group in groups:
            for variable in variables:

                if variable == 'Latitude' or variable == 'Longitude':
                    continue
                # Replace collection, group, variable in template
                [variable_name] = replace_cgv(logger, collection, group, variable,
                                              variable_name_template)

                # Extract the data from the collections
                cgv = split_collectiongroupvariable(logger, variable_name)
                exp_var_data = data_collections.get_variable_data_array(cgv[0], cgv[1], cgv[2])

                for stat_function in stat_functions:
                    function_name = getattr(exp_var_data, stat_function.lower())
                    result = function_name(dim=stat_dim)
                    # Add the new field to the data collections
                    cgv = split_collectiongroupvariable(logger, variable_name)
                    data_collections.add_variable_to_collection(cgv[0], cgv[1]+stat_function,
                                                                cgv[2], result)

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