[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Working patch for FFTW 3.0.x and Nd FFT's

From: Daniel J Sebald
Subject: Re: Working patch for FFTW 3.0.x and Nd FFT's
Date: Tue, 17 Feb 2004 10:21:37 -0600
User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.2) Gecko/20021120 Netscape/7.01

David Bateman wrote:

According to Daniel J Sebald <address@hidden> (on 02/16/04):
Any ramifications of fft_wisdom not being correct on server environments?

Do the fft_wisdom functions remove the existing wisdom files at the very end of the trial and error process? Otherwise mistakingly running the command could lead to anguish.

This is a difficult issue. The way I treated it was

1) The system wisdom file (usually in /etc/fftw/wisdom) is imported at startup. Hopefully, the user won't install an incorrect wisdom file here. 2) The fft_wisdom command can import or export wisdom files. These can
  be used to override the system wisdom if needed
3) There is a flag to 'fft_wisdom' that forces it to overwrite a wisdom file even if it exists.
4) Furthemore, if 'fft_wisdom([257 257])' for example is called, the process
  is to create an octave temporary file in $(TMPDIR)/oct-*. Invoke with
  'system' the command 'fftw-wisdom -n -o $(TMPDIR)/oct-*'. The '-n' forces
  the process to not use the system wisdom, so that bad wisdom can also
  be overridden in this manner. The temporrary file is deleted when octave
  exits and so won't be reused.

There are still ways the user can import bad wisdom, for instance calling
fft_wisdom('file') thinking that 'file' doesn't exist, when it does and
contains wisdom for anotehr platform. Do you think it is worth splitting
fft_wisdom into three commands? fft_save_wisdom, fft_load_wisdom and fft_create_wisdom?

No, probably not. It is common for the meaning of an Octave function to be dependent upon the type of variable passed into it, or not passed in.

would set up Octave to use a wisdom file other than the default, fine.

fft_wisdom()  -- prints the contents of the wisdom file?
would run wisdom and overwrite the default file.  Maybe this is a bit dodgy.

save 'mywisdom.wis' fft_wisdom();
I'm not sure about the saving portion of it.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]