# FFTW

Presented by Chaiwoot Boonyasiriwat
## Introduction

FFTW is a public library for computing the discrete Fourier transform
in one or more dimensions. Their benchmarks show that FFTW is the fastest
public FFT software. This is crucial for codes with large computational
loads. You might want to make every step of your code run as fast as possible.
For more information go to the website:
FFTW
## Example Codes

Currently, I have an example code in Fortran 90. If you want some examples
in C or Fortran 77, please tell me. CHPC only installed FFTW on the clusters.
Therefore, you have to log in to a cluster to compile and run the code.
Once you have downloaded the following files, type "make". An executable
file "fft" will be generated. You can simply type "fft" to run it.
If you get an error about PathScale compiler, do the following.
source /uufs/CLUSTER/sys/pkg/pscale/std/etc/pscale.csh

where CLUSTER is your current cluster name, e.g., "landscapearch.arches".
**Fortran 90**