Arithmetic

Applies arithmetic transformations to data variables within the provided data collections. It iterates over the specified collections, groups, and variables, and applies arithmetic expressions as defined in the ‘equals’ expression within the configuration. The resulting variables are added to the data collections.

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

Returns:
    None

This is an example of the config dictionary:

Example:
    config = {
        'collections': [...],
        'groups': [...],
        'variables': [...],
        'new name': 'result_variable',
        'equals': '(${collection}::${group}::${var1} + ${collection}::${group}::${var2}) / 2'
    }

The configuration components are defined as:

• new name: name of the resulting variable which will be added to data_collections

• equals: the result of the arithmetic expression applied to the specified variables within data_collections

Arithmetic filter for batch processing

To apply the arithmetic filter to a yaml for batch processing:

transforms:

  - transform: arithmetic
    new name: collection_name::new_group_name::${variable}
    equals: collection_name::curr_group_1::${variable}-collection_name::curr_group_2::${variable}
    for:
      variable: *variables

variables are defined in datasets and are referenced in the transform filter. equals is an arithmetic expression (+, -, /, *) with groups that can be found in the collection labeled collection_name.

Arithmetic filter for interactive processing

To apply the arithmetic filter during an eva interactive session:

    expression = 'curr_group_1-curr_group_2'
    EvaInteractive.arithmetic(new_group_name, expression, collection_name)

The parameters for arithmetic are

• new_group_name: new name to label transformed group

• expression: arithmetic expression using groups currently in collection

• collection_name: name of the collection that contains group to be transformed