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FFTW comes with a configure program in the GNU style.
Chris@10: Installation can be as simple as:
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./configure Chris@10: make Chris@10: make install Chris@10:Chris@10:
This will build the uniprocessor complex and real transform libraries
Chris@10: along with the test programs. (We recommend that you use GNU
Chris@10: make if it is available; on some systems it is called
Chris@10: gmake.) The “make install” command installs the fftw
Chris@10: and rfftw libraries in standard places, and typically requires root
Chris@10: privileges (unless you specify a different install directory with the
Chris@10: --prefix flag to configure). You can also type
Chris@10: “make check” to put the FFTW test programs through their paces.
Chris@10: If you have problems during configuration or compilation, you may want
Chris@10: to run “make distclean” before trying again; this ensures that
Chris@10: you don't have any stale files left over from previous compilation
Chris@10: attempts.
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The configure script chooses the gcc compiler by default,
Chris@10: if it is available; you can select some other compiler with:
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./configure CC="<the name of your C compiler>" Chris@10:Chris@10:
The configure script knows good CFLAGS (C compiler flags)
Chris@10: for a few systems. If your system is not known, the configure
Chris@10: script will print out a warning. In this case, you should re-configure
Chris@10: FFTW with the command
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./configure CFLAGS="<write your CFLAGS here>" Chris@10:Chris@10:
and then compile as usual. If you do find an optimal set of
Chris@10: CFLAGS for your system, please let us know what they are (along
Chris@10: with the output of config.guess) so that we can include them in
Chris@10: future releases.
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configure supports all the standard flags defined by the GNU
Chris@10: Coding Standards; see the INSTALL file in FFTW or
Chris@10: the GNU web page.
Chris@10: Note especially --help to list all flags and
Chris@10: --enable-shared to create shared, rather than static, libraries.
Chris@10: configure also accepts a few FFTW-specific flags, particularly:
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--enable-float: Produces a single-precision version of FFTW
Chris@10: (float) instead of the default double-precision (double).
Chris@10: See Precision.
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Chris@10: --enable-long-double: Produces a long-double precision version of
Chris@10: FFTW (long double) instead of the default double-precision
Chris@10: (double). The configure script will halt with an error
Chris@10: message if long double is the same size as double on your
Chris@10: machine/compiler. See Precision.
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Chris@10: --enable-quad-precision: Produces a quadruple-precision version
Chris@10: of FFTW using the nonstandard __float128 type provided by
Chris@10: gcc 4.6 or later on x86, x86-64, and Itanium architectures,
Chris@10: instead of the default double-precision (double). The
Chris@10: configure script will halt with an error message if the
Chris@10: compiler is not gcc version 4.6 or later or if gcc's
Chris@10: libquadmath library is not installed. See Precision.
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Chris@10: --enable-threads: Enables compilation and installation of the
Chris@10: FFTW threads library (see Multi-threaded FFTW), which provides a
Chris@10: simple interface to parallel transforms for SMP systems. By default,
Chris@10: the threads routines are not compiled.
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Chris@10: --enable-openmp: Like --enable-threads, but using OpenMP
Chris@10: compiler directives in order to induce parallelism rather than
Chris@10: spawning its own threads directly, and installing an ‘fftw3_omp’ library
Chris@10: rather than an ‘fftw3_threads’ library (see Multi-threaded FFTW). You can use both --enable-openmp and --enable-threads
Chris@10: since they compile/install libraries with different names. By default,
Chris@10: the OpenMP routines are not compiled.
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Chris@10: --with-combined-threads: By default, if --enable-threads
Chris@10: is used, the threads support is compiled into a separate library that
Chris@10: must be linked in addition to the main FFTW library. This is so that
Chris@10: users of the serial library do not need to link the system threads
Chris@10: libraries. If --with-combined-threads is specified, however,
Chris@10: then no separate threads library is created, and threads are included
Chris@10: in the main FFTW library. This is mainly useful under Windows, where
Chris@10: no system threads library is required and inter-library dependencies
Chris@10: are problematic.
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Chris@10: --enable-mpi: Enables compilation and installation of the FFTW
Chris@10: MPI library (see Distributed-memory FFTW with MPI), which provides
Chris@10: parallel transforms for distributed-memory systems with MPI. (By
Chris@10: default, the MPI routines are not compiled.) See FFTW MPI Installation.
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Chris@10: --disable-fortran: Disables inclusion of legacy-Fortran
Chris@10: wrapper routines (see Calling FFTW from Legacy Fortran) in the standard
Chris@10: FFTW libraries. These wrapper routines increase the library size by
Chris@10: only a negligible amount, so they are included by default as long as
Chris@10: the configure script finds a Fortran compiler on your system.
Chris@10: (To specify a particular Fortran compiler foo, pass
Chris@10: F77=foo to configure.)
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Chris@10: --with-g77-wrappers: By default, when Fortran wrappers are
Chris@10: included, the wrappers employ the linking conventions of the Fortran
Chris@10: compiler detected by the configure script. If this compiler is
Chris@10: GNU g77, however, then two versions of the wrappers are
Chris@10: included: one with g77's idiosyncratic convention of appending
Chris@10: two underscores to identifiers, and one with the more common
Chris@10: convention of appending only a single underscore. This way, the same
Chris@10: FFTW library will work with both g77 and other Fortran
Chris@10: compilers, such as GNU gfortran. However, the converse is not
Chris@10: true: if you configure with a different compiler, then the
Chris@10: g77-compatible wrappers are not included. By specifying
Chris@10: --with-g77-wrappers, the g77-compatible wrappers are
Chris@10: included in addition to wrappers for whatever Fortran compiler
Chris@10: configure finds.
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Chris@10: --with-slow-timer: Disables the use of hardware cycle counters,
Chris@10: and falls back on gettimeofday or clock. This greatly
Chris@10: worsens performance, and should generally not be used (unless you don't
Chris@10: have a cycle counter but still really want an optimized plan regardless
Chris@10: of the time). See Cycle Counters.
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Chris@10: --enable-sse, --enable-sse2, --enable-avx,
Chris@10: --enable-altivec, --enable-neon: Enable the compilation of
Chris@10: SIMD code for SSE (Pentium III+), SSE2 (Pentium IV+), AVX (Sandy Bridge,
Chris@10: Interlagos), AltiVec (PowerPC G4+), NEON (some ARM processors). SSE,
Chris@10: AltiVec, and NEON only work with --enable-float (above). SSE2
Chris@10: works in both single and double precision (and is simply SSE in single
Chris@10: precision). The resulting code will still work on earlier CPUs
Chris@10: lacking the SIMD extensions (SIMD is automatically disabled, although
Chris@10: the FFTW library is still larger).
Chris@10: gcc, you may have to use the
Chris@10: -mabi=altivec option when compiling any code that links to FFTW,
Chris@10: in order to properly align the stack; otherwise, FFTW could crash when
Chris@10: it tries to use an AltiVec feature. (This is not necessary on MacOS X.)
Chris@10: gcc, you should use a version of gcc that
Chris@10: properly aligns the stack when compiling any code that links to FFTW.
Chris@10: By default, gcc 2.95 and later versions align the stack as
Chris@10: needed, but you should not compile FFTW with the -Os option or the
Chris@10: -mpreferred-stack-boundary option with an argument less than 4.
Chris@10: gcc flags for generating
Chris@10: NEON code. In general, you will have to provide them on the command line.
Chris@10: This command line is known to have worked at least once:
Chris@10: ./configure --with-slow-timer --host=arm-linux-gnueabi \ Chris@10: --enable-single --enable-neon \ Chris@10: "CC=arm-linux-gnueabi-gcc -march=armv7-a -mfloat-abi=softfp" Chris@10:Chris@10:
To force configure to use a particular C compiler foo
Chris@10: (instead of the default, usually gcc), pass CC=foo to the
Chris@10: configure script; you may also need to set the flags via the variable
Chris@10: CFLAGS as described above.
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