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slight restructuring, clean up

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This commit is contained in:
Mark Borgerding
2003-08-09 14:22:30 +00:00
parent db556661ed
commit b95e3ea18a
6 changed files with 24 additions and 193 deletions
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README
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@ -12,10 +12,14 @@ USAGE:
void * cfg = kiss_fft_alloc( nfft ,inverse_fft );
while ...
...
... // put kth sample in cx_buf_in_out[k].r and cx_buf_in_out[k].i
kiss_fft( cfg , cx_buf_in_out );
...
... // transformed
free(cfg);
Note: frequency-domain data is stored from dc to 2pi.
so cx_buf_in_out[0] is the dc bin of the FFT
and cx_buf_in_out[nfft/2] is the Nyquist bin
Declarations are in "kiss_fft.h", along with a brief description of the
two functions you'll need to use. Code definitions are in kiss_fft.c, along
@ -53,8 +57,8 @@ last bit of performance.
PERFORMANCE:
(on Athlon XP 2100+, with gcc 2.96, optimization O3, float data type)
Kiss performed 1000 1024-pt ffts in 136 ms. This translates to 7.5 Msamples/s.
Just for comparison, it took md5sum 160 ms to process the same amount of data
Kiss performed 1000 1024-pt ffts in 110 ms of cpu time (132ms real time).
For comparison, it took md5sum 160ms cputime to process the same amount of data
DO NOT:
... use Kiss if you need the absolute fastest fft in the world
@ -67,13 +71,16 @@ UNDER THE HOOD:
addressing is corrected as the last step in the transform. No scaling is done.
LICENSE:
BSD, see COPYING for details.
BSD, see COPYING for details. Basically, "free to use, give credit where due, no guarantees"
TODO:
Make the fixed point scaling and bit shifts more easily configurable.
Document/revisit the input/output fft scaling
See if the fixed point code can be optimized a little without adding complexity.
*) Add sample code for parallel ffts (stereo) packed into re,im components of time sequence.
*) Add simple windowing function, e.g. Hamming : w(i)=.54-.46*cos(2pi*i/(n-1))
*) Could mixed-radix FFTs be made simple enough to stand by the KISS principle?
*) Make the fixed point scaling and bit shifts more easily configurable.
*) Document/revisit the input/output fft scaling
*) See if the fixed point code can be optimized a little without adding complexity.
AUTHOR:
Mark Borgerding
mark@borgerding.net
Mark@Borgerding.net