| Re: Using FFTW with IDL?? [message #37326] |
Tue, 09 December 2003 16:06 |
Richard French
Messages: 173
Registered: December 2000
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Senior Member |
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On 12/9/03 11:32 AM, in article
330af58b.0312090832.64a41e2c@posting.google.com, "Jeff" <jnettle1@utk.edu>
wrote:
> Just out of curiosity, why would you use this kind of dll over IDL's fft
> function?
>
> Cheers,
> Jeff
>
1) You can do REAL FFTs rather then complex ones, cutting the size of the
arrays in half, which can be significant for very large arrays that press
the limits of available RAM;
2) For large arrays, the FFTs are about three times faster, using FFTW, in
the applications I use.
I've succeeded in getting FFTW2.3.1 working on Solaris and COMPAQ Tru64,
using a DLM to make the routine callable from IDL. What I have NOT succeeded
in doing is getting FFTW3.0 working with a DLM under MAC OS X. I can't
successfully compile the DLM. I get error messages:
ld: warning multiple definitions of symbol _XauDisposeAuth
/usr/X11R6/lib/libX11.6.dylib(AuDispose.o) definition of _XauDisposeAuth
/usr/X11R6/lib/libXp.6.dylib(AuDispose.o) definition of _XauDisposeAuth
ld: warning multiple definitions of symbol _XauReadAuth
/usr/X11R6/lib/libX11.6.dylib(AuRead.o) definition of _XauReadAuth
/usr/X11R6/lib/libXp.6.dylib(AuRead.o) definition of _XauReadAuth
ld: /usr/local/lib/libfftw3.a(q1_3.o) has external relocation entries in
non-writable section (__TEXT,__text) for symbols:
restFP
saveFP
make[1]: *** [rfftwnd.so] Error 1
make: *** [all] Error 2
I have not been able to figure out how to load what is libidl.so in Solaris
but which appears to be a host of other shared object libraries under Mac OS
X.
Dick French
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| Re: Using FFTW with IDL?? [message #37341 is a reply to message #37326] |
Tue, 09 December 2003 08:32  |
jnettle1
Messages: 27
Registered: January 2001
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Junior Member |
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Just out of curiosity, why would you use this kind of dll over IDL's fft function?
Cheers,
Jeff
"Brian" <brian.huether@NOdlrSPAM.de> wrote in message news:<c9adde4a2a413838f2ae58b9b2a76664@news.teranews.com>...
> Hi,
>
> I am fairly new to IDL, and when it comes to calling external code, I am
> pretty clueless. I downloaded the windows binary from www.fftw.org. But now
> what? As I understand, the first thing one must do is create a "plan" that
> fftw uses to optimize its speed on a given platform. So does the fftw3.dll
> provide all this functionality? What is the calling convention like? Is
> someone willing to post a short tutorial that details the process (i.e. a
> tutorial that goes through the steps of creating the "plan", executing the
> fft, reusing the plan)?
>
> thanks,
>
> brian
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