Re: Working patch for FFTW 3.0.x and Nd FFT's

[David Bateman]

According to Daniel J Sebald <address@hidden> (on 02/18/04):
> 
> That was sort of my original concern, about the user getting stuck in 
> some situation he or she doesn't know what is going on.  (I'm wondering 
> what could possibly be taking 12 hours, but that's a different matter.)

FFTW tests all possible ways it knows of to do a particular FFT and this
stores the information on the best one for the current architecture.
With the command "fftw-wisdom -c -v -o /etc/fftw/wisdom" it tests about
8 different ways FFTW might be called to do a particular FFT for the
following FFT sizes


     "1", "2", "4", "8", "16", "32", "64", "128", "256", "512", "1024",
     "2048", "4096", "8192", "16384", "32768", "65536", "131072",
     "262144", "524288", "1048576",

     "10", "100", "1000", "10000", "100000", "1000000",

     "2x2", "4x4", "8x8", "10x10", "16x16", "32x32", "64x64", "100x100",
     "128x128", "256x256", "512x512", "1000x1000", "1024x1024",

     "2x2x2", "4x4x4", "8x8x8", "10x10x10", "16x16x16", "32x32x32",
     "64x64x64", "100x100x100"

So its a lot of work.

> Why not the name fft_wisdom as opposed to fftw_wisdom?  I realize that 
> FFTW is being used, but if later some other FFT package is used then 
> fft_wisdom could still apply.  (I may have come in late on this discussion.)

My original patch had fft_wisdom, John preferred fftw_wisdom. He has CVS
write access, so he has the last say :-)

D.

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David Bateman                                address@hidden
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