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FFTW Frequently Asked Questions with Answers
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FFTW Frequently Asked Questions with Answers
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This is the list of Frequently Asked Questions about FFTW, a
collection of fast C routines for computing the Discrete Fourier
Transform in one or more dimensions.
<h1>
Index
</h1>
<ul>
<li><b><font size="+2"><a href="section1.html" rel=subdocument>Section 1. Introduction and General Information
</a></font></b>
<li><a href="section1.html#whatisfftw" rel=subdocument>Q1.1. What is FFTW?
</a>
<li><a href="section1.html#whereisfftw" rel=subdocument>Q1.2. How do I obtain FFTW?
</a>
<li><a href="section1.html#isfftwfree" rel=subdocument>Q1.3. Is FFTW free software?
</a>
<li><a href="section1.html#nonfree" rel=subdocument>Q1.4. What is this about non-free licenses?
</a>
<br><br><li><b><font size="+2"><a href="section2.html" rel=subdocument>Section 2. Installing FFTW
</a></font></b>
<li><a href="section2.html#systems" rel=subdocument>Q2.1. Which systems does FFTW run on?
</a>
<li><a href="section2.html#runOnDOS" rel=subdocument>Q2.2. Does FFTW run on DOS/Windows?
</a>
<li><a href="section2.html#compilerCrashes" rel=subdocument>Q2.3. My compiler crashes when compiling FFTW.
</a>
<li><a href="section2.html#solarisSucks" rel=subdocument>Q2.4. FFTW does not compile on Solaris, complaining about
<code>const
</code>.
</a>
<li><a href="section2.html#languages" rel=subdocument>Q2.5. Which language is FFTW written in?
</a>
<li><a href="section2.html#fortran" rel=subdocument>Q2.6. Can I call FFTW from FORTRAN?
</a>
<li><a href="section2.html#cplusplus" rel=subdocument>Q2.7. Can I call FFTW from C++?
</a>
<li><a href="section2.html#whynotfortran" rel=subdocument>Q2.8. Why isn't FFTW written in FORTRAN/C++?
</a>
<li><a href="section2.html#singleprec" rel=subdocument>Q2.9. How do I compile FFTW to run in single precision?
</a>
<br><br><li><b><font size="+2"><a href="section3.html" rel=subdocument>Section 3. Using FFTW
</a></font></b>
<li><a href="section3.html#slow" rel=subdocument>Q3.1. FFTW seems really slow.
</a>
<li><a href="section3.html#conventions" rel=subdocument>Q3.2. FFTW gives results different from my old
FFT.
</a>
<li><a href="section3.html#savePlans" rel=subdocument>Q3.3. Can I save FFTW's plans?
</a>
<li><a href="section3.html#whyscaled" rel=subdocument>Q3.4. Why does your inverse transform return a scaled
result?
</a>
<li><a href="section3.html#centerorigin" rel=subdocument>Q3.5. How can I make FFTW put the origin (zero frequency) at the center of
its output?
</a>
<li><a href="section3.html#imageaudio" rel=subdocument>Q3.6. How do I FFT an image/audio file in
<i>foobar
</i> format?
</a>
<li><a href="section3.html#linkfails" rel=subdocument>Q3.7. My program does not link (on Unix).
</a>
<br><br><li><b><font size="+2"><a href="section4.html" rel=subdocument>Section 4. Internals of FFTW
</a></font></b>
<li><a href="section4.html#howworks" rel=subdocument>Q4.1. How does FFTW work?
</a>
<li><a href="section4.html#whyfast" rel=subdocument>Q4.2. Why is FFTW so fast?
</a>
<li><a href="section4.html#wisdom" rel=subdocument>Q4.3. What is this
<code>wisdom
</code> thing?
</a>
<li><a href="section4.html#whywisdom" rel=subdocument>Q4.4. Why do you use
<code>wisdom
</code>? I just wanted to save a plan.
</a>
<br><br><li><b><font size="+2"><a href="section5.html" rel=subdocument>Section 5. Known bugs
</a></font></b>
<li><a href="section5.html#rfftwndbug" rel=subdocument>Q5.1. FFTW 1.1 crashes in rfftwnd on Linux.
</a>
<li><a href="section5.html#fftwmpibug" rel=subdocument>Q5.2. The MPI transforms in FFTW 1.2 give incorrect results/leak
memory.
</a>
<li><a href="section5.html#testsingbug" rel=subdocument>Q5.3. The test programs in FFTW 1.2.1 fail when I change FFTW to use single
precision.
</a>
<li><a href="section5.html#teststoobig" rel=subdocument>Q5.4. The test program in FFTW 1.2.1 fails for n
>
46340.
</a>
<li><a href="section5.html#linuxthreads" rel=subdocument>Q5.5. The threaded code fails on Linux Redhat 5.0
</a>
<li><a href="section5.html#bigrfftwnd" rel=subdocument>Q5.6. FFTW 2.0's rfftwnd fails for rank
> 1 transforms with a final
dimension
>= 65536.
</a>
<li><a href="section5.html#primebug" rel=subdocument>Q5.7. FFTW 2.0's complex transforms give the wrong results with prime
factors 17 to 97.
</a>
<li><a href="section5.html#mpichbug" rel=subdocument>Q5.8. FFTW 2.1.1's MPI test programs crash with
MPICH.
</a>
</ul><hr>
<address>
<A href="http://theory.lcs.mit.edu/~fftw/">Matteo Frigo and Steven G. Johnson
</A> /
<A href="mailto:fftw@theory.lcs.mit.edu">fftw@theory.lcs.mit.edu
</A>
- 18 May 1999
</address><br>
Extracted from FFTW Frequently Asked Questions with Answers,
Copyright
© 1999 Massachusetts Institute of Technology.
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