Extracts the fitted contrasts as a long data frame (one row per
contrast x voxel), optionally prefixed with the job id so results stack
cleanly across subjects. Surfaces template-level contrasts (those passed to
fmri_template(), applied by run_job()) when present, otherwise the
model's formula-embedded contrasts via coef(). Returns a zero-row frame
when no contrasts are defined.
Value
A reducer function suitable for fmri_template().
See also
Other reducers:
reduce_betas(),
reduce_identity(),
reduce_write_results()