Parallel FFTs in Molsim

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Name Parallel FFTs in Molsim
Description Performance improvement of the SPME in Molsim
Project financing   SNIC
Is active yes
Start date 2012-04
End date


Molsim deploys an SMPE (smooth particle mesh Ewald) algorithm to evaluate the long range interactions. When deploying a larger number of processors the original implementation of the FFT proved to be a performance bottle neck. The project takes a two stage approach to the problem:

  • Replacing the originally deployed FFT library (compiled Fortran-source) with the high performance library FFTW
  • Upgrading the original serial transformation with an parallel transformation using MPI

The replacement of the FFT library with FFTW has been accomplished in July 2012. When comparing the performance to the originally deployed FFT library, FFTW turned out to be 4.5 times faster.

The parallisation of the Fourier transformation routines is ongoing.


Joachim Hein (LUNARC)LUNARCApplication expertParallel programming
Performance optimisation