can GMP FFT be accessed directly?

Paul Zimmermann Paul.Zimmermann at
Fri Dec 16 06:01:10 CET 2005

   Date: Wed, 14 Dec 2005 19:20:01 -0800
   From: David Hillman <dhi at>


   I'm wondering whether it is possible currently for a user to access the 
   GMP FFT directly. That is: intercept the results after the convolution 
   and before the last step where things are added at the appropriate digit 
   place and carrying is done and so forth.

   If so, how? (I didn't see this in the manual.) And if not, wouldn't that 
   be a good idea? (For people who want to do convolution, and not 


I wrote an interface that enables you to perform the direct and inverse
transforms separately, together with the pointwise multiplies: (FFT patch for gmp-4.1.4)

Note however that this patch uses non-public functions of GMP, thus it is
not sure it will work in future versions!

Paul Zimmermann

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