[GRASS5] i.fft segemntation fault

Stephan Holl sholl at gmx.net
Fri Jun 11 06:48:55 EDT 2004

Hello Glynn, 

On Thu, 10 Jun 2004 19:08:08 +0100 Glynn Clements
<glynn.clements at virgin.net> wrote:

> The memory requirements could be reduced to two doubles per cell
> (without scaling up to a power of two) if i.fft used FFTW directly,
> rather than using the fft() interface. Or to two floats per cell if
> FFTW was built to use float instead of double.
As this seems to be an option for reducing the memory-needs a little, is
this a doable task? I think it would be benefit when FFTW is used
directly instead of fft(). Correct me when I am wrong, please...

If so, how much work would that be?

> > so the only possible solution would be tiling the map into smaller
> > pices which fit into my RAM (768MB) and calculating the fft on the
> > small tiles.
> Or, if you don't need the highest frequencies, just reduce the region
> resolution.

Thanks for the suggestion, as I need the resolution this is no option.

	Stephan Holl

Stephan Holl

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