Re: FFT Speed

*To*: mathgroup at smc.vnet.net*Subject*: [mg121982] Re: FFT Speed*From*: roby <roby.nowak at gmail.com>*Date*: Sat, 8 Oct 2011 05:31:57 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <j6mf50$7hu$1@smc.vnet.net>

On 7 Okt., 11:01, to <todu... at gmail.com> wrote: > 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. Well, you may avoid the Flatten: Map[Fourier[#, FourierParameters -> {1, -1}] &,data,{2}] no idea what speed gain (if any) this will give. Regards Robert