Much of the stuff that is supposed to be on this page has not yet moved over from the old website.
Software
April 6th, 2009
Patrick Stein
Common Lisp vs. C/ASM: Battle FFT
October 16th, 2009
Patrick Stein
Dr. David McClain of Refined Audiometrics sent me his code for interfacing with the Apple vDSP library. Here it is along with a Makefile that I put together for it: vdsp-wrapper.tar.gz. I have not actually run the code myself. I started to convert his Lispworks FLI code to CFFI code, but bailed [...]
Adventures in Package Dependencies
October 14th, 2009
Patrick Stein
A variety of people have asked how the speed of my Lisp Fourier Transform Library compares to an FFI call to the FFTW Library. I downloaded the FFTW Library, built it, and installed it. Then, I tried to get someone else’s FFI wrappers for the FFTW Library going. I worked on this [...]
Lisp Fourier Transform Library Faster Yet (v1.3)
October 13th, 2009
Patrick Stein
I released version 1.3 of my Common Lisp Fourier Transform library today. It is significantly faster than yesterday’s version. On my MacBook Pro in SBCL 1.0.30 with a 512 by 512 by 16 array, version 1.3 takes 3.74 seconds where version 1.2 took 9.77 seconds and version 1.0 took 25.31 seconds. For a breakdown [...]
Lisp Fourier Transform Library Faster
October 12th, 2009
Patrick Stein
I released version 1.2 of my Common Lisp Fourier Transform library today. It is significantly faster than the old version. On my MacBook Pro in SBCL 1.0.30 with a 512 by 512 by 16 array, version 1.2 takes 9.77 seconds where version 1.0 took 25.31 seconds. Version 1.2 consed 2.4M while version [...]
Public Domain Fourier Transform Library for Common Lisp
October 7th, 2009
Patrick Stein
In response to my recent post about genetically selecting cosine waves for image approximation, several reddit commentors said that I should just have taken the Fourier transform, kept the largest 100 coefficients and did the inverse Fourier transform. [I haven't run the RMS calculation on the result yet, but visually, it looks pretty nice [...]