fft-test

Mercurial revision 5786:5c8b45563631 | 2026-08-04

Description

fft-test is a utility developed as part of the T-UGO tools (2006-2011) under the Unstructured Ocean Grid initiative. It tests the equivalence between FFT implementations in the FFTPACK and GSL (GNU Scientific Library) libraries.

This tool is primarily intended for validation and comparison purposes, ensuring consistency between the two FFT libraries.

Note: This program does not accept command-line arguments. It runs predefined tests internally.

Output

The program will output the results of the FFT transformations for both libraries, allowing you to compare their equivalence. Example output:

vvv --- n=5 j=4 --- vvv
FFTPACK results
0
0
0
0
1

GSL FFT results
1 
0.309017 
0.951057 
-0.809017 
0.587785 
^^^ --- n=5 j=4 --- ^^^

Notes

  1. Dependencies:

  • FFTPACK: A widely used library for computing Fast Fourier Transforms (FFTs).

  • GSL (GNU Scientific Library): A numerical library for C and C++ programmers, providing FFT routines for real data.

  1. Test Cases:

  • The program tests FFT transformations for arrays of sizes n=4 and n=5.

  • For each size, it tests impulse responses (e.g., value = 1 if i == j, else 0).

  1. Output Interpretation:

  • The output displays the FFT results for both libraries side by side.

  • Users can visually compare the results to ensure equivalence.

  1. Purpose:

  • This tool is not intended for production use but rather for debugging and validation of FFT implementations.

See Also