Development/FFTW

The main documentation is available via module help numlib/mkl on the cluster. Most software modules for applications provide working example batch scripts.

Description	Content
module load	numlib/mkl
License	Commercial. See EULA.
Citing	n/a
Links	Intel MKL Homepage | FFTW Homepage
Graphical Interface	No

Description

The Fastest Fourier Transform in the West (FFTW) is a software library for computing discrete Fourier transforms 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). FFTW was developed by Matteo Frigo and Steven G. Johnson at the Massachusetts Institute of Technology.

The Intel Math Kernel Library (Intel MKL) offers FFTW2 (for version 2.x) and FFTW3 (for version 3.x) interfaces to the Intel MKL Fast Fourier Transform and Trigonometric Transform functionality. These interfaces enable applications using FFTW to gain performance with Intel MKL without changing the application source code. Therefore, it is highly recommended to use Intel MKL instead of a separate FFTW installation.

FAQ

Q: Why does no separate FFTW module exist on the cluster?

A: MKL is more performant (see Figure on the right). Therefore, we would like to advice you that you use MKL and decided not to offer a separate FFTW installation.

Q: Why does my code complain about argument of type "long double *" is incompatible with parameter of type "double *" ?

A: The interfaces do not support long double precision because Intel MKL FFT functions operate only on single- and double-precision floating point data types. For the very rare case that you need extended data types, please contact 'compchem [at] bwhpc.de' or submit a trouble ticket at https://www.bwhpc.de/supportportal.

Useful links

• Documentation (english)
• Wikipedia article (german)
• Wikipedia article (english)

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