[GRASS5] i.fft segemntation fault

[Glynn Clements]

Otto Dassau wrote:

> I tried to use i.fft in GRASS 5.3 (CVS) but only get errors like:
> 
> a) Starting FFT...
> fftw: BUG in executor: invalid plan
> 
> b) Starting FFT...
> Speicherzugriffsfehler (segmentation fault)
> 
> Does this module work at all?

Yes.

> Is there a special way to use it?

No.

> I installed fftw RPMs. Is this version broken?
> 
> fftw-2.1.3-1102  ?
> fftw-devel-2.1.3-1102   ?

Maybe. The code which actually uses FFTW is:

	plan = fftw2d_create_plan(
		dimc, dimr,
		(i_sign < 0) ? FFTW_FORWARD : FFTW_BACKWARD,
		FFTW_ESTIMATE | FFTW_IN_PLACE);

	fftwnd_one(plan, data, data);

	fftwnd_destroy_plan(plan);

Examining the source code of FFTW 2.1.3 indicates that the above error
message always corresponds to an invalid plan type. According to the
documentation, fftw2d_create_plan() will always return either a valid
plan or NULL (and NULL would result in a segfault).

-- 
Glynn Clements <glynn.clements at virgin.net>