Clearer licensing documentation #728
Description
Discussed in #727
Originally posted by iboB August 28, 2025
The code in this repo is (mostly) under the Apache 2.0 license
HOWEVER:
- The CPU version relies on one of:
- FFTW3 which is GPLv2 with option to buy a proprietary license from MIT
- ducc which is GPLv2 with some BSD elements, but if ducc is used, it's not just the BSD elements, but GPLv2 licensed code too. ducc doesn't seem to provide an alternative to GPLv2
- The GPU version uses cufft, which is subject to the standard NVIDIA math lib license.
Not clearly documenting these facts may be a bit misleading to users, who might carelessly assume that finufft is entirely Apache 2.0, whereas, depending on the configuration, it "carries" one of several copyleft licenses with it.
I think this information should be more prominently displayed in the docs and readme.