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All of the FFTW threads code is located in the threads
Chris@10: subdirectory of the FFTW package. On Unix systems, the FFTW threads
Chris@10: libraries and header files can be automatically configured, compiled,
Chris@10: and installed along with the uniprocessor FFTW libraries simply by
Chris@10: including --enable-threads in the flags to the configure
Chris@10: script (see Installation on Unix), or --enable-openmp to use
Chris@10: OpenMP threads.
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The threads routines require your operating system to have some sort
Chris@10: of shared-memory threads support. Specifically, the FFTW threads
Chris@10: package works with POSIX threads (available on most Unix variants,
Chris@10: from GNU/Linux to MacOS X) and Win32 threads. OpenMP threads, which
Chris@10: are supported in many common compilers (e.g. gcc) are also supported,
Chris@10: and may give better performance on some systems. (OpenMP threads are
Chris@10: also useful if you are employing OpenMP in your own code, in order to
Chris@10: minimize conflicts between threading models.) If you have a
Chris@10: shared-memory machine that uses a different threads API, it should be
Chris@10: a simple matter of programming to include support for it; see the file
Chris@10: threads/threads.c for more detail.
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You can compile FFTW with both --enable-threads and
Chris@10: --enable-openmp at the same time, since they install libraries
Chris@10: with different names (‘fftw3_threads’ and ‘fftw3_omp’, as
Chris@10: described below). However, your programs may only link to one
Chris@10: of these two libraries at a time.
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Ideally, of course, you should also have multiple processors in order to Chris@10: get any benefit from the threaded transforms. Chris@10: Chris@10: Chris@10: Chris@10: