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FFTW comes with a configure program in the GNU style.
Installation can be as simple as:
./configure make make install
This will build the uniprocessor complex and real transform libraries
along with the test programs. (We recommend that you use GNU
make if it is available; on some systems it is called
gmake.) The "make install" command installs the fftw
and rfftw libraries in standard places, and typically requires root
privileges (unless you specify a different install directory with the
--prefix flag to configure). You can also type
"make check" to put the FFTW test programs through their paces.
If you have problems during configuration or compilation, you may want
to run "make distclean" before trying again; this ensures that
you don't have any stale files left over from previous compilation
attempts.
The configure script chooses the gcc compiler by default,
if it is available; you can select some other compiler with:
./configure CC="<the name of your C compiler>"
The configure script knows good CFLAGS (C compiler flags)
for a few systems. If your system is not known, the configure
script will print out a warning. In this case, you should re-configure
FFTW with the command
./configure CFLAGS="<write your CFLAGS here>"and then compile as usual. If you do find an optimal set of
CFLAGS for your system, please let us know what they are (along
with the output of config.guess) so that we can include them in
future releases.
configure supports all the standard flags defined by the GNU
Coding Standards; see the INSTALL file in FFTW or
the GNU web page.
Note especially --help to list all flags and
--enable-shared to create shared, rather than static, libraries.
configure also accepts a few FFTW-specific flags, particularly:
--enable-float: Produces a single-precision version of FFTW
(float) instead of the default double-precision (double).
See Precision.
--enable-long-double: Produces a long-double precision version of
FFTW (long double) instead of the default double-precision
(double). The configure script will halt with an error
message is long double is the same size as double on your
machine/compiler. See Precision.
--enable-threads: Enables compilation and installation of the
FFTW threads library (see Multi-threaded FFTW), which provides a
simple interface to parallel transforms for SMP systems. (By default,
the threads routines are not compiled.)
--with-openmp, --with-sgimp: In conjunction with
--enable-threads, causes the multi-threaded FFTW library to use
OpenMP or SGI MP compiler directives in order to induce parallelism,
rather than spawning its own threads directly. (Useful especially for
programs already employing such directives, in order to minimize
conflicts between different parallelization mechanisms.)
--disable-fortran: Disables inclusion of Fortran-callable wrapper
routines (see Calling FFTW from Fortran) in the standard FFTW
libraries. These wrapper routines increase the library size by only a
negligible amount, so they are included by default as long as the
configure script finds a Fortran compiler on your system.
--with-slow-timer: Disables the use of hardware cycle counters,
and falls back on gettimeofday or clock. This greatly
worsens performance, and should generally not be used (unless you don't
have a cycle counter but still really want an optimized plan regardless
of the time). See Cycle Counters.
--enable-sse, --enable-sse2, --enable-k7,
--enable-altivec: Enable the compilation of SIMD code for SSE
(Pentium III+), SSE2 (Pentium IV+), 3dNow! (AMD K7 and others), or
AltiVec (PowerPC G4+). SSE, 3dNow!, and AltiVec only work with
--enable-float (above), while SSE2 only works in double precision
(the default). The resulting code will still work on earlier
CPUs lacking the SIMD extensions (SIMD is automatically disabled,
although the FFTW library is still larger).
--enable-k7 (which uses
assembly), require a compiler supporting SIMD extensions, and compiler
support is still a bit flaky. We have tested SIMD with gcc
versions 3.x (which miscompile AltiVec permutations on Linux, but we
have an assembly workaround) and with Intel's icc 6.0 (which
misaligns SSE constants, but we have a workaround). Some 3.x versions
of gcc crash during compilation, and gcc 2.95 miscompiles
AltiVec on MacOS X.
gcc, you may have to use the
-mabi=altivec option when compiling any code that links to FFTW,
in order to properly align the stack; otherwise, FFTW could crash when
it tries to use an AltiVec feature. (This is not necessary on MacOS X.)
gcc, you should use a version of gcc that
properly aligns the stack when compiling any code that links to FFTW.
By default, gcc 2.95 and later versions align the stack as
needed, but you should not use the -Os option or the
-mpreferred-stack-boundary option with an argument less than 4.
To force configure to use a particular C compiler (instead of the
default, usually gcc), set the environment variable CC to
the name of the desired compiler before running configure; you
may also need to set the flags via the variable CFLAGS.