Developer Reference

  • 2021.2
  • 03/26/2021
  • Public Content
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Multi-threaded FFTW

This section discusses multi-threaded FFTW wrappers only. MPI FFTW wrappers, available only with
Intel® oneAPI Math Kernel Library
for the Linux* and Windows* operating systems, are described in
a separate section
.
Unlike the original FFTW interface, every computational function in the FFTW2 interface to
Intel® oneAPI Math Kernel Library
provides multithreaded computation by default, with the maximum number of threads permitted in FFT functions (see "Techniques to Set the Number of Threads" in
Intel® oneAPI Math Kernel Library
Developer Guide
). To limit the number of threads, call the threaded FFTW computational functions:
void fftw_threads(int
nthreads
, fftw_plan
plan
, int
howmany
, fftw_complex
*in
, int
istride
, int
idist
, fftw_complex
*out
, int
ostride
, int
odist
);
void fftw_threads_one(int
nthreads
, rfftwnd_plan
plan
, fftw_complex
*in
, fftw_complex
*out
);
...
void rfftwnd_threads_real_to_complex( int
nthreads
, rfftwnd_plan
plan
, int
howmany
, fftw_real
*in
, int
istride
, int
idist
, fftw_complex
*out
, int
ostride
, int
odist
);
Compared to its non-threaded counterpart, every threaded computational function has
threads_
as the second part of its name and additional first parameter
nthreads
. Set the
nthreads
parameter to the thread limit to ensure that the computation requires at most that number of threads.
Product and Performance Information
Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.
Notice revision #20201201

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.