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cannam@167:All of the FFTW threads code is located in the threads
cannam@167: subdirectory of the FFTW package. On Unix systems, the FFTW threads
cannam@167: libraries and header files can be automatically configured, compiled,
cannam@167: and installed along with the uniprocessor FFTW libraries simply by
cannam@167: including --enable-threads in the flags to the configure
cannam@167: script (see Installation on Unix), or --enable-openmp to use
cannam@167: OpenMP threads.
cannam@167:
cannam@167:
The threads routines require your operating system to have some sort
cannam@167: of shared-memory threads support. Specifically, the FFTW threads
cannam@167: package works with POSIX threads (available on most Unix variants,
cannam@167: from GNU/Linux to MacOS X) and Win32 threads. OpenMP threads, which
cannam@167: are supported in many common compilers (e.g. gcc) are also supported,
cannam@167: and may give better performance on some systems. (OpenMP threads are
cannam@167: also useful if you are employing OpenMP in your own code, in order to
cannam@167: minimize conflicts between threading models.) If you have a
cannam@167: shared-memory machine that uses a different threads API, it should be
cannam@167: a simple matter of programming to include support for it; see the file
cannam@167: threads/threads.c for more detail.
cannam@167:
You can compile FFTW with both --enable-threads and
cannam@167: --enable-openmp at the same time, since they install libraries
cannam@167: with different names (‘fftw3_threads’ and ‘fftw3_omp’, as
cannam@167: described below). However, your programs may only link to one
cannam@167: of these two libraries at a time.
cannam@167:
Ideally, of course, you should also have multiple processors in order to cannam@167: get any benefit from the threaded transforms. cannam@167:
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