GPL-2 payload for niimath's optional -spm_coreg and -spm_deface commands — a C port of SPM's spm_coreg rigid-body coregistration (John Ashburner, Wellcome Centre for Human Neuroimaging). Used as the src/GPL git submodule of niimath.
niimath itself is BSD-2-Clause. Building it with this module (make GPL=1 / cmake -DENABLE_GPL=ON) produces a GPL-2 combined-work binary; the default niimath build does not include this code and stays BSD-2-Clause.
The module computes only the rigid transform (estimate). niimath's own BSD code applies it (reslice / mask warp / header rewrite). Files: cost hist2 loaduint8 matrix powell reslice smooth spm_coreg (+ headers) and the niimath glue spmcoreg_niimath.
See LICENSE (GNU GPL-2) and NOTICE (SPM attribution).