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FFT usage

Posted: Wed May 15, 2019 12:15 pm
by jcharris
Is there any function within Code_Saturne which computes an FFT? Would it be possible to call it from a user subroutine?

Obviously it would be possible to write a custom FFT function into a user subroutine, likely overly long or inefficient in the process, but if it (or a library that contained an FFT) was already used elsewhere in the code, it might be nice to use.

(I have some existing code which could be interesting to use as a boundary condition or initial condition, and which is probably a bit "heavy" to write into a pre-processing script, but could be put as a user subroutine if an FFT existed.)

Re: FFT usage

Posted: Thu May 16, 2019 3:04 pm
by Yvan Fournier

There is no built-in function, but this has been done in user subroutines on several occasions, usually with the fftw library.

I have some relatively recent example from a colleague's intern which did good work but which I have not had the time to check out yet. Other colleague's (mainly the turbulence specialists) may have other examples available.

I'll check.

Best regards,