coonfit.parallel_helpers
========================

.. py:module:: coonfit.parallel_helpers

.. autoapi-nested-parse::

   Internal worker functions for parallelized regression computations.

   This module contains the individual job functions executed by worker processes
   in the ``coonfit`` parallel pipeline. These functions are not part of the
   public API and are called exclusively by :mod:`~coonfit.parallel`.

   Worker functions cover:

   - **Matrix aggregation**: Combining partial ``X.T @ X`` or beta matrices
     received from a multiprocessing queue (:func:`_combine_matrices`).
   - **Partial products**: Computing ``X.T @ X`` and beta coefficients for a
     single spatial block (:func:`_partial_transposed_product`,
     :func:`_partial_optimal_betas`).
   - **Predictor validation**: Counting valid pixels per predictor band and
     checking that each band meets the minimum contribution threshold
     (:func:`_process_band_count_valid`, :func:`_check_predictor_consistency`).
   - **Model prediction**: Applying fitted regression weights to a spatial block
     to produce model output values (:func:`_block_model_prediction`).
   - **Goodness-of-fit**: Partially computing the sum of squared residuals (SSR)
     and total sum of squares (SST) for RMSE and R² evaluation
     (:func:`_block_ssr`, :func:`_block_sst`).