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MathGroup Archive 2011

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FFT Speed

  • To: mathgroup at smc.vnet.net
  • Subject: [mg121961] FFT Speed
  • From: to <todummy at gmail.com>
  • Date: Fri, 7 Oct 2011 04:48:40 -0400 (EDT)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com

I have a 3D matrix with dimensions {355,647,8}.  For each {x,y} I need
to compute the FFT along the z dimension, i.e. 355*647 FFTs of 8
elements each.  The fastest way I found to do this was

Partition[Map[Fourier[#, FourierParameters -> {1, -1}] &,
Flatten[data, 1]], dimx];

I was wondering if there are faster ways to do this.  The reason I ask
is because another package for numerical computations can do this a
lot faster compared to my solution (nearly two orders of magnitude
faster !)

I tried using ParallelMap but this makes things even slower.



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