A lightweight C# wrapper for native FFTW.
- Unmanaged function calls to main FFTW functions for both single and double precision
- Basic managed wrappers for FFTW plans and unmanaged arrays
- Test program that demonstrates basic functionality
The native libraries are no longer distributed with this project. Up-to-date versions can be obtained on conda. The current conda package (version 3.3.9, Feb 2021) has no SIMD features enabled. You can download a custom package with SSE2 enabled here. For an official (but outdated) package go to the FFTW downloads. Be aware that the DLLs provided in the official package must be renamed to fftw3.dll and fftw3f.dll respectively (or alternatively, the library names in both NativeMethods.cs files can be adapted).
The FFT benchmark fftbench compares a selection of managed libraries (Accord, AForge, Exocortex, Lomont, MathNet, NAudio, NWaves) with FFTW. The benchmark was originally written for a CodeProject article Comparison of FFT Implementations for .NET. Here's an example output. The first column displays the relative speedup (slowdown) compared to Exocortex:
FFT size: 2^12 (4096)
Repeat: 80
[13/13] Done
FFTWF (real): 0.2 [min: 13.07, max: 23.09, mean: 13.91, stddev: 1.58]
FFTW (real): 0.3 [min: 22.45, max: 29.72, mean: 23.13, stddev: 1.16]
FFTW: 0.6 [min: 44.38, max: 54.68, mean: 46.08, stddev: 2.33]
Exocortex (real): 1.0 [min: 73.41, max: 87.08, mean: 74.40, stddev: 1.71]
Lomont (real): 1.2 [min: 83.59, max: 145.93, mean: 91.67, stddev: 8.83]
NWaves (real): 1.6 [min: 108.90, max: 134.05, mean: 121.49, stddev: 5.93]
NWaves: 1.8 [min: 131.83, max: 160.96, mean: 133.78, stddev: 3.88]
Lomont: 2.2 [min: 161.74, max: 179.24, mean: 165.22, stddev: 3.96]
NAudio: 2.3 [min: 165.75, max: 302.79, mean: 169.82, stddev: 15.28]
Exocortex: 2.4 [min: 171.52, max: 193.15, mean: 175.00, stddev: 4.60]
AForge: 3.1 [min: 224.57, max: 264.78, mean: 228.89, stddev: 5.33]
Accord: 4.0 [min: 286.49, max: 352.00, mean: 298.92, stddev: 12.66]
Math.NET: 4.9 [min: 331.12, max: 441.35, mean: 360.87, stddev: 17.33]
Timing in microseconds.
One of the earliest .NET open-source FFT projects and - as the benchmark confirms - still one of the best performing. The copy provided here was updated to .NET standard 2.0 and uses the System.Numerics.Complex type. Exocortex.DSP is distributed under the BSD license.