Re: [patch] Use fftw if available

[Trond Varslot]

Hello,
I think it would be a great idea to give the option of using FFTW if this is 
installed on the computer. It should be included in the main octave tree, 
though, and not distributed as a separate patch. Octave is able to use BLAS and 
LAPACK. FFTW should be treated the same way.

Now, my problems emerged when trying your patch out. It applies fine, but 
somehow I get lots of compilation errors of the sort

>/usr/src/build/octave-2.1.33/liboctave/dMatrix.cc:761: undefined reference to 
>`cffti_'
>/usr/src/build/octave-2.1.33/liboctave/dMatrix.cc:764: undefined reference to 
>`cfftf_'
>/usr/src/build/octave-2.1.33/liboctave/dMatrix.cc:776: undefined reference to 
>`cffti_'
>/usr/src/build/octave-2.1.33/liboctave/dMatrix.cc:783: undefined reference to 
>`cfftf_'
>../liboctave/liboctave.a(dMatrix.o): In function `Matrix::ifourier2d(void) 
>const':
>/usr/src/build/octave-2.1.33/liboctave/dMatrix.cc:821: undefined reference to 
>`cffti_'
>/usr/src/build/octave-2.1.33/liboctave/dMatrix.cc:824: undefined reference to 
>`cfftb_'
>/usr/src/build/octave-2.1.33/liboctave/dMatrix.cc:839: undefined reference to 
>`cffti_'
>/usr/src/build/octave-2.1.33/liboctave/dMatrix.cc:846: undefined reference to 
>`cfftb_'
>collect2: ld returned 1 exit status
>make[2]: *** [octave] Error 1
>make[2]: Leaving directory `/usr/src/build/octave-2.1.33/src'
>make[1]: *** [src] Error 2
>make[1]: Leaving directory `/usr/src/build/octave-2.1.33'
>make: *** [all] Error 2

I have not had time to look into what causes these problems, but octave 
compiles nicely without your patch, so it must be introducing something.
Which version of octave was this patch done against? Which version of fftw did 
you use? I tried this on octave-2.1.33 with fftw-2.1.3.

I would really like to try it out, as I am currently doing some work which 
depends rather heavily on fft.


Yours sincerely
Trond Varslot.