Re: Where is fft.m file

[David Bateman]

I think you need to understand a little more about octave, and where files
are. A short tutorial, is that octave can have functions implemented in either

  * a dot-m file, which is a file with the .m extension. These files 
   contain code written with the matlab/octave language itself.

  * an oct-file, which is a file with surprise the .oct extension. This is
   the equivalent of the matlab .mex file, and is ode written in a compilable
   language that allows optimum performance. As the oct-file is compiled it
   is binary and is useless for you to understand the code, you need the source
   of the oct-file which in your case is in src/DLD-FUNCTIONS/fft.cc, or on the
   web at

   
http://www.octave.org/cgi-bin/viewcvs.cgi/octave/src/DLD-FUNCTIONS/fft.cc?rev=HEAD&view=auto

The code in fft.cc in fact calls the methods of NDArray and
ComplexNDArray like ::fourier or ::ifourier which can be found in
liboctave/dNDArray.cc or liboctave/CNDArray.cc. Now, the reason
Octave's FFT is so fast is that octave uses the FFTW library to do the
fft's rather than do anything itself. So the code in Octave itself
won't tell you why its fast. All it might tell you is how to use
FFTW....

D.


According to Rahul Sanghavi <address@hidden> (on 08/04/04):
> Hi Ganesh
>  
> I cann't find fft.m file. so pls get me the path of fft.m file because i see
> this code & understand how actually fft work fast compare to dft.Because i
> already written code for dft it take good time but octave inbuilt fft inst.
> take hardly 1 sec. so i try to find this code but unfortunately they give only
> fft.oct. So pls help me.
>  
> Regards
>  
> Rahul Sanghavi
> System Engineer
> Tectona SoftSolutions Pvt. Ltd.
> 101, Rajsi, Rajvansh Complex,
> Bodakdev, Ahmedabad - 380 054
> Gujarat, INDIA
> Phone No.+91- 79- 26852006
> Fax No.    +91- 79- 26844192

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