The Program

Three programs were done to study the attractor, all of them in ForTran, writing results in matlab files.

To Download the code click here

The Three Programs : User's Guide

The first program is obtained by compiling calcul_unique.f. It does the computation of the serie for one set of parameters asked just after the program is launched.
The second program, obtained after compilation of calcul_tous.f does the same computation, but for a range of lambda and beta specified.
The third program, called master and slave, are used after using make. They need PVM to run. It does the same thing as the second program, but using n processors, and writing n files at a time.

All programs can export Matlab files or standard text files in the format "x y". Matlab files are executed ubder Matlab abd automatically plot the result, storing the coordinates of the points in a matrix A, and a matrix B.

Known bugs :
*The program tends to crash if asked to calculate very large simulations (over 30000 for calcul_unique, and over 10000 for the parallel version)

The codes

Direct computing

The algorithm is very simple. It is a loop over the number of iterations asked by the user, storing the coordinates of the series in two vectors. The vectors, once build are then stored in a result file.

Compute many parameters

The algorithm is a modified version of the direct computing program. It loops over the direct computing program, feeding it with different lambda and betas, in a standard loop :

do while beta less than beta max

lambda=lambda start

do while lambda less than lambda max

calculate the serie

increase lambda

end do

increase beta

end do

Parallel computation on a set of parameters

Programmed under PVM, this program uses the initialization given in a program developed by Mr. Dayde. The rest was written specially for this task. It consists in distrtibuting the direct computing of one parameter to many processes. This allows a gain of time, compared to the second program, but is limited by the speed of the Hard disk of the computer used for storage, since many files are saved at the same time.