[LAD] malloc in fftw

Folderol folderol at ukfsn.org
Wed Apr 7 11:28:42 UTC 2010

On Wed, 07 Apr 2010 21:25:10 +1000
cal <cal at graggrag.com> wrote:

> Maarten de Boer wrote:
> > Hi,
> > 
> > I suppose that many of you are or might be using fftw for real-time audio processing, and I think the following information may be of your interest.
> > 
> > I just came to realize that fftw_execute calls malloc. This happens even though you create a 'plan' where you pass fftw_malloc preallocated input and output buffers.
> > [ ... ]
> > I wrote the fftw developers and they confirmed the memory allocation takes place. They suggested the following:
> > 
> >> Try planning with the undocumented flag FFTW_NO_BUFFERING, which will
> >> prevent the use of malloc() in common cases.  This is not
> >> foolproof---some transforms are very hard to do without additional
> >> buffers, but if all you are trying to do is vanilla out-of-place 1D
> >> transforms without large prime factors it should work.
> Very interesting ... yoshimi still works with it in play, though it'll take a good
> deal more testing (and some thinking) to see if it makes a difference in my case.
> Thanks for that!
> cheers, Cal

I wondered if you would pick up on this. I was about to send you an
email :)

Will J Godfrey
Say you have a poem and I have a tune.
Exchange them and we can both have a poem, a tune, and a song.

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