# Building FFTW

**This file documents the use of the x86 Open64 Compiler Suite.**

© 2009 Advanced Micro Devices, Inc.

### FFTW Info

FFTW stands for Fastest Fourier Transform in the
West. 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).
To build FFTW, you will need to download the source, build it with the
suggested flags, and install it. These steps, and any known
limitations, are described in the sections below.

Download:
FFTW (version 2.1.5).

### Building FFTW

In brief, the following steps are sufficient to build Namd and its
dependent applications from the command line:

Part 1, fftw:

>mkdir ~/fftw
>cd ~/fftw
>mkdir src
>cd src

copy the tar file to this directory, then proceed with the following
on the command line:

>tar -xvjf fftw-3.1.3.tar.bz2
>cd fftw-3.1.3
>export CC=opencc F77=openf90 CFLAGS=-O3 FFLAGS=-O3
>export MY_FFTW_PATH=~/fftw
>./configure --enable-float --enable-type-prefix --enable-static \
--prefix=$MY_FFTW_PATH
>make
>make install

### Known Limitations

There are no known limitations.