# FFTW/fftw3

DO NOT CHECK OUT THESE FILES FROM GITHUB UNLESS YOU KNOW WHAT YOU ARE DOING. (See below.)

Repository: https://github.com/FFTW/fftw3
Canonical: https://ross.abutalabs.com/products/fftw3
Language: C
License: GPL-2.0
License Family: copyleft
Last push: 2026-06-10T11:17:52+00:00

## Health v2 (maintenance only)
Score: 62/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 86, release rhythm 8, longevity 100
- inputs: {"age_days": 4917, "days_push": 84, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 3102, forks 716 (observed 2026-08-28T04:07:43.615466+00:00)

## What it is
FFTW is a widely used C library for computing discrete Fourier transforms (DFTs), known for its speed and adaptive code generation. This repository is the source generator; most users should download official release tarballs from fftw.org instead.

## Use cases
- compute fast fourier transforms in c
- signal processing fft library
- spectral analysis of audio or sensor data
- solve pdes with spectral methods
- fast convolution and correlation
- image frequency-domain filtering

## When to choose
- you need a high-performance, well-tested FFT implementation in C/C++
- you need transforms of arbitrary sizes with multi-dimensional support
- you want a mature library with bindings in many languages

## When to avoid
- you want to build directly from this GitHub repo - it contains only generated-code generators
- you need GPU-accelerated FFTs (consider cuFFT)
- you need a permissive license - FFTW is GPL-2.0 (commercial licenses available)

## Facets
- artifact type: library
- maturity: stable
- function: math, developer-tools
- domain: performance, cross-platform
- platform: windows, cpp, c, cross-platform
- tags: fft, fourier-transform, signal-processing, numerical-computing, scientific-computing, algorithms, linux, macos

## Member repositories
- FFTW/fftw3 (main) score 62

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:43.615466+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:46:19.907841+00:00, confidence not recorded.
  - readme: https://github.com/FFTW/fftw3 (fetched 2026-08-28T04:07:43.615466+00:00, sha 40c93160c155)
- Data as of 2026-08-30T08:39:29.467469+00:00.