blender_rules.rst

Model Blender Rules

Blending models relies on rules to define how to evaluate all the input values for a model attribute in order to determine the final output value. These rules then get specified in the model schema for each attribute.

The rules get interpreted and applied as list or array operations that work on the set of input values for each attribute. The full set of pre-defined rules includes

import numpy as np
# translation dictionary for function entries from rules files
blender_funcs = {'first': first,
                  'last': last,
                  'float_one': float_one,
                  'int_one': int_one,
                  'zero': zero,
                  'multi': multi,
                  'multi?': multi1,
                  'mean': np.mean,
                  'sum': np.sum,
                  'max': np.max,
                  'min': np.min,
                  'stddev': np.std,
                  'mintime': mintime,
                  'maxtime': maxtime,
                  'mindate': mindate,
                  'maxdate': maxdate,
                  'mindatetime': mindatetime,
                  'maxdatetime': maxdatetime}

The rules that should be referenced in the model schema definition are the keys defined for jwst.model_blender.blender_rules.blender_funcs listed above. This definition illustrates how several rules are simply interfaces for numpy array operations, while others are defined internally to model_blender.

.. automodapi:: jwst.model_blender.blendrules
  :no-inheritance-diagram: