High Performance Computing Using Serial Applications: Exploiting Tools Of The Queue System.

Abstract

During the last years we have been witnesses to an impressive growth in the calculation
power of computational systems. Furthermore, software tools and programming languages have followed
these advances providing new techniques and programming paradigms to use the installed hardware in
more efficient ways, including the use of parallel programming. Unfortunately, to take full advantage
of the power of these computational systems it is necessary, in most cases, to rewrite and optimize
our older routines and, more often than not, to attack the problem again from scratch. Nowadays it is
usual for many people working in research institutions to have access to a cluster of computers managed
by an intelligent queue system. This tool allows to manage the load and the different users priorities
efficiently. In this work we show how it is possible to continue using our old and reliable routines,
written in any language, and, at the same time, to take advantage of a simple distribution technique to
reduce dramatically the computational time. We will show several examples where we have applied this
technique emphasizing the fact that it is not necessary to modify substantially our original programs.
These examples comprise different problems in collision physics, some of them including Monte Carlo
approaches, and processes in laser-atom and molecule interactions, in which it is necessary to deal with
Fourier Transforms techniques.