Development/FFTW
| Description | Content |
|---|---|
| module load | numlib/fftw |
| Availability | bwUniCluster | BwForCluster_Chemistry |
| License | GPL | License and Copyright |
| Citing | Authors |
| Links | FFTW Homepage | Documentation |
| Graphical Interface | No |
Description
FFTW is a C subroutine library for computing the discrete Fourier transform (DFT) in one or more dimensions, of arbitrary input size, and of both real and complex data (as well as of even/odd data, i.e. the discrete cosine/sine transforms or DCT/DST). We believe that FFTW, which is free software, should become the FFT library of choice for most applications.
More infos about FFTW
This package provides three versions of the fftw3 library depending on precision:
- libfft3
- libfftw3f
- libfftw3l for double, single and long-double precision libraries
Documentation
Online
Local
- info fftw3
- man fftw-wisdom
- man fftw-wisdom-to-conf
See also documentation folder pointed to by shell variable $FFTW_DOC_DIR.
Versions and Availability
A list of versions currently available on all bwHPC-C5-Clusters can be obtained from the
Cluster Information System CIS
{{#widget:Iframe |url=https://cis-hpc.uni-konstanz.de/prod.cis/bwUniCluster/numlib/fftw |width=99% |height=200 |border=0 }} On the command line interface of any bwHPC cluster you'll get a list of available versions by using the command 'module avail chem/gamess'.
$ module avail chem/gamess ------------------------ /opt/bwhpc/common/modulefiles ------------------------- chem/gamess/12052014
Loading the Module
Load the fftw module, and, if needed, the corresponding openmpi and compiler module. You can load the default version of 'FFTW with the command 'module load numlib/fftw'.
$ module load numlib/fftw Loading module dependency 'compiler/intel/13.1'.
The module will try to load modules it needs to function (e.g. compiler, mpi, numlibs).
If loading the module fails, check if you have already loaded one of those modules with
the command 'module list'.
If you wish to load a specific (older) version (if available), you can do so using e.g.
'module load numlib/fftw/'version' to load the version you desires.
$ module avail numlib/fftw ------------------------ /opt/bwhpc/common/modulefiles ------------------------- numlib/fftw/3.3.3-impi-4.1.1-gnu-4.4 numlib/fftw/3.3.3-impi-4.1.1-intel-13.1(default) $ $ module load numlib/fftw/3.3.3-impi-4.1.1-gnu-4.4 $ module list Currently Loaded Modulefiles: 1) numlib/fftw/3.3.3-impi-4.1.1-gnu-4.4
Beware! Compiler, MPI-module and numerical library must fit!
Hints for compiling and linking
FFTW Specific Environments
To see a list of all FFTW environments set by the 'module load'-command use the command
'module display numlib/fftw'.
After having loaded the appropriate module(s), you can use several environment variables to compile and link your application.
$ module display numlib/fftw ------------------------------------------------------------------- /opt/bwhpc/common/modulefiles/numlib/fftw/3.3.3-impi-4.1.1-intel-13.1: FTW_VERSION = 3.3.3-impi-4.1.1-intel-13.1 FFTW_HOME = /opt/bwhpc/common/numlib/fftw/3.3.3-impi-4.1.1-intel-13.1 FFTW_BIN_DIR = /opt/bwhpc/common/numlib/fftw/3.3.3-impi-4.1.1-intel-13.1/bin FFTW_INC_DIR = /opt/bwhpc/common/numlib/fftw/3.3.3-impi-4.1.1-intel-13.1/include FFTW_LIB_DIR = /opt/bwhpc/common/numlib/fftw/3.3.3-impi-4.1.1-intel-13.1/lib FFTW_STA_DIR = /opt/bwhpc/common/numlib/fftw/3.3.3-impi-4.1.1-intel-13.1/lib FFTW_SHA_DIR = (empty) FFTW_MAN_DIR = /opt/bwhpc/common/numlib/fftw/3.3.3-impi-4.1.1-intel-13.1/share/man FFTW_INF_DIR = /opt/bwhpc/common/numlib/fftw/3.3.3-impi-4.1.1-intel-13.1/share/info FFTW_DOC_DIR = /opt/bwhpc/common/numlib/fftw/3.3.3-impi-4.1.1-intel-13.1/doc FFTW_EXA_DIR = /opt/bwhpc/common/numlib/fftw/3.3.3-impi-4.1.1-intel-13.1/examples FFTW_WWW = http://www.fftw.org/ PATH = /opt/bwhpc/common/numlib/fftw/3.3.3-impi-4.1.1-intel-13.1/bin:$PATH MANPATH = /opt/bwhpc/common/numlib/fftw/3.3.3-impi-4.1.1-intel-13.1/share/man:$MANPATH INFOPATH = /opt/bwhpc/common/numlib/fftw/3.3.3-impi-4.1.1-intel-13.1/share/info:$INFOPATH LD_LIBRARY_PATH = /opt/bwhpc/common/numlib/fftw/3.3.3-impi-4.1.1-intel-13.1/lib:$LD_LIBRARY_PATH [...]
Compile a Serial Program
$ gcc example.c -o example -I$FFTW_INC_DIR -L$FFTW_LIB_DIR -lfftw3 -lm
with POSIX Threads
Compile program with support for POSIX threads.
$ gcc example.c -o example -I$FFTW_INC_DIR -L$FFTW_LIB_DIR -lfftw3_threads -lfftw3 -lpthread -lm
Compile program with support for OpenMP threads
$ gcc example.c -o example -fopenmp -I$FFTW_INC_DIR -L$FFTW_LIB_DIR -lfftw3_omp -lfftw3 -lm
Compile program with support for MPI
$ mpicc example.c -o example -I$FFTW_INC_DIR -L$FFTW_LIB_DIR -lfftw3_mpi -lfftw3 -lm
Run program with MPI support
$ mpirun -n <ncpu> ./example
(Replace <ncpu> by number of processor cores.)
Replace -lfftw3, -lfftw3_threads, etc. by -lfftw3f, -lfftw3f_threads, etc. for single precision and by -lfftw3l, -lfftw3l_threads etc. for long-double precision codes, respectively.
These commands will compile your program with dynamic fftw library versions in which case you also have to have the fftw module loaded for running the program. Alternatively, you may want to link your program with static fftw library versions. With static fftw libraries it is only necessary to load the fftw module for compiling but not for executing the program.
Compile program with static fftw library versions
Example for POSIX threads support
$ gcc example.c -o example -I$FFTW_INC_DIR $FFTW_LIB_DIR/{libfftw3_threads.a,libfftw3.a} -lpthread -lm
or:
$ gcc example.c -o example -I$FFTW_INC_DIR -L$FFTW_LIB_DIR -Wl,-Bstatic -lfftw3 -lfftw3_threads \
-Wl,-Bdynamic -lpthread -lm
Environment variables $FFTW_INC_DIR, $FFTW_LIB_DIR etc. are available after loading the module.
Sample Code
Sample code for various test cases is provided in folder pointed to by environment variable $FFTW_EXA_DIR.
$ module list Currently Loaded Modulefiles: 1) compiler/intel/13.1 2) numlib/fftw/3.3.3-impi-4.1.1-intel-13.1(default) $ ls -F $FFTW_EXA_DIR ex_mpi_2d.c ex_serial_1d.c fftw3f-test.c ex_ompthreads_2d.c ex_serial_2d.c fftw3l-test.c ex_pthreads_2d.c ex_serial_3d.c fftw3-test.c $ echo $FFTW_EXA_DIR /opt/bwhpc/common/numlib/fftw/3.3.3-impi-4.1.1-intel-13.1/examples