FFTW 3.3.8: Installation on Unix

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10.1 Installation on Unix

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FFTW comes with a configure program in the GNU style. Chris@82: Installation can be as simple as: Chris@82: Chris@82:

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./configure
Chris@82: make
Chris@82: make install
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This will build the uniprocessor complex and real transform libraries Chris@82: along with the test programs. (We recommend that you use GNU Chris@82: make if it is available; on some systems it is called Chris@82: gmake.) The “make install” command installs the fftw Chris@82: and rfftw libraries in standard places, and typically requires root Chris@82: privileges (unless you specify a different install directory with the Chris@82: --prefix flag to configure). You can also type Chris@82: “make check” to put the FFTW test programs through their paces. Chris@82: If you have problems during configuration or compilation, you may want Chris@82: to run “make distclean” before trying again; this ensures that Chris@82: you don’t have any stale files left over from previous compilation Chris@82: attempts. Chris@82:

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The configure script chooses the gcc compiler by default, Chris@82: if it is available; you can select some other compiler with: Chris@82:

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./configure CC="<the name of your C compiler>"
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The configure script knows good CFLAGS (C compiler flags) Chris@82: Chris@82: for a few systems. If your system is not known, the configure Chris@82: script will print out a warning. In this case, you should re-configure Chris@82: FFTW with the command Chris@82:

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./configure CFLAGS="<write your CFLAGS here>"
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and then compile as usual. If you do find an optimal set of Chris@82: CFLAGS for your system, please let us know what they are (along Chris@82: with the output of config.guess) so that we can include them in Chris@82: future releases. Chris@82:

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configure supports all the standard flags defined by the GNU Chris@82: Coding Standards; see the INSTALL file in FFTW or Chris@82: the GNU web page. Chris@82: Note especially --help to list all flags and Chris@82: --enable-shared to create shared, rather than static, libraries. Chris@82: configure also accepts a few FFTW-specific flags, particularly: Chris@82:

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Chris@82: --enable-float: Produces a single-precision version of FFTW Chris@82: (float) instead of the default double-precision (double). Chris@82: See Precision. Chris@82: Chris@82:
Chris@82: --enable-long-double: Produces a long-double precision version of Chris@82: FFTW (long double) instead of the default double-precision Chris@82: (double). The configure script will halt with an error Chris@82: message if long double is the same size as double on your Chris@82: machine/compiler. See Precision. Chris@82: Chris@82:
Chris@82: --enable-quad-precision: Produces a quadruple-precision version Chris@82: of FFTW using the nonstandard __float128 type provided by Chris@82: gcc 4.6 or later on x86, x86-64, and Itanium architectures, Chris@82: instead of the default double-precision (double). The Chris@82: configure script will halt with an error message if the Chris@82: compiler is not gcc version 4.6 or later or if gcc’s Chris@82: libquadmath library is not installed. See Precision. Chris@82: Chris@82:
Chris@82: --enable-threads: Enables compilation and installation of the Chris@82: FFTW threads library (see Multi-threaded FFTW), which provides a Chris@82: simple interface to parallel transforms for SMP systems. By default, Chris@82: the threads routines are not compiled. Chris@82: Chris@82:
--enable-openmp: Like --enable-threads, but using OpenMP Chris@82: compiler directives in order to induce parallelism rather than Chris@82: spawning its own threads directly, and installing an ‘fftw3_omp’ library Chris@82: rather than an ‘fftw3_threads’ library (see Multi-threaded FFTW). You can use both --enable-openmp and --enable-threads Chris@82: since they compile/install libraries with different names. By default, Chris@82: the OpenMP routines are not compiled. Chris@82: Chris@82:
--with-combined-threads: By default, if --enable-threads Chris@82: is used, the threads support is compiled into a separate library that Chris@82: must be linked in addition to the main FFTW library. This is so that Chris@82: users of the serial library do not need to link the system threads Chris@82: libraries. If --with-combined-threads is specified, however, Chris@82: then no separate threads library is created, and threads are included Chris@82: in the main FFTW library. This is mainly useful under Windows, where Chris@82: no system threads library is required and inter-library dependencies Chris@82: are problematic. Chris@82: Chris@82:
Chris@82: --enable-mpi: Enables compilation and installation of the FFTW Chris@82: MPI library (see Distributed-memory FFTW with MPI), which provides Chris@82: parallel transforms for distributed-memory systems with MPI. (By Chris@82: default, the MPI routines are not compiled.) See FFTW MPI Installation. Chris@82: Chris@82:
Chris@82: --disable-fortran: Disables inclusion of legacy-Fortran Chris@82: wrapper routines (see Calling FFTW from Legacy Fortran) in the standard Chris@82: FFTW libraries. These wrapper routines increase the library size by Chris@82: only a negligible amount, so they are included by default as long as Chris@82: the configure script finds a Fortran compiler on your system. Chris@82: (To specify a particular Fortran compiler foo, pass Chris@82: F77=foo to configure.) Chris@82: Chris@82:
--with-g77-wrappers: By default, when Fortran wrappers are Chris@82: included, the wrappers employ the linking conventions of the Fortran Chris@82: compiler detected by the configure script. If this compiler is Chris@82: GNU g77, however, then two versions of the wrappers are Chris@82: included: one with g77’s idiosyncratic convention of appending Chris@82: two underscores to identifiers, and one with the more common Chris@82: convention of appending only a single underscore. This way, the same Chris@82: FFTW library will work with both g77 and other Fortran Chris@82: compilers, such as GNU gfortran. However, the converse is not Chris@82: true: if you configure with a different compiler, then the Chris@82: g77-compatible wrappers are not included. By specifying Chris@82: --with-g77-wrappers, the g77-compatible wrappers are Chris@82: included in addition to wrappers for whatever Fortran compiler Chris@82: configure finds. Chris@82: Chris@82: Chris@82:
--with-slow-timer: Disables the use of hardware cycle counters, Chris@82: and falls back on gettimeofday or clock. This greatly Chris@82: worsens performance, and should generally not be used (unless you don’t Chris@82: have a cycle counter but still really want an optimized plan regardless Chris@82: of the time). See Cycle Counters. Chris@82: Chris@82:
--enable-sse (single precision), Chris@82: --enable-sse2 (single, double), Chris@82: --enable-avx (single, double), Chris@82: --enable-avx2 (single, double), Chris@82: --enable-avx512 (single, double), Chris@82: --enable-avx-128-fma, Chris@82: --enable-kcvi (single), Chris@82: --enable-altivec (single), Chris@82: --enable-vsx (single, double), Chris@82: --enable-neon (single, double on aarch64), Chris@82: --enable-generic-simd128, Chris@82: and Chris@82: --enable-generic-simd256: Chris@82: Chris@82:
Enable various SIMD instruction sets. You need compiler that supports Chris@82: the given SIMD extensions, but FFTW will try to detect at runtime Chris@82: whether the CPU supports these extensions. That is, you can compile Chris@82: with--enable-avx and the code will still run on a CPU without AVX Chris@82: support. Chris@82:
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- - These options require a compiler supporting SIMD extensions, and Chris@82: compiler support is always a bit flaky: see the FFTW FAQ for a list of Chris@82: compiler versions that have problems compiling FFTW. Chris@82:
- - Because of the large variety of ARM processors and ABIs, FFTW Chris@82: does not attempt to guess the correct gcc flags for generating Chris@82: NEON code. In general, you will have to provide them on the command line. Chris@82: This command line is known to have worked at least once: Chris@82:
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```
./configure --with-slow-timer --host=arm-linux-gnueabi \
Chris@82:   --enable-single --enable-neon \
Chris@82:   "CC=arm-linux-gnueabi-gcc -march=armv7-a -mfloat-abi=softfp"
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```
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To force configure to use a particular C compiler foo Chris@82: (instead of the default, usually gcc), pass CC=foo to the Chris@82: configure script; you may also need to set the flags via the variable Chris@82: CFLAGS as described above. Chris@82: Chris@82:

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