Sunday, May 20, 2018

MathLab for the baggars


Want to use a computer algebra tool but you can afford it? A nice alternative i encountered recently is SciLab (see, which is very much like MATHLAB for numerical computation and simulation and as of today it is open source and consequently much more affordable then MathLab. It contains a neat graphical subsystem which unfortunately does not work out of the box since the version 5.5.X  (see Error Report).

Fig.1 The function values of D(x,y) projected  on  a 2d canvas.

Fixing the Grafics stuff with Fedora Workstation 28.

But it can be fixed with a few configuration changes. In the installation directory of SciLab you will find in the bin directory a file scilab-adv-cli where you can disable the usage of the OpenGL hardware support. The line below has to be added to to this file:

# * That is all. Don't hesitate to contact us if you see one missing.
After you have done this change start SciLab and run the command plot() which should
draw some test pattern in a drawing window.


The following lines create the sin curve in the figure below.

Fig. 2 simple sin(x) created by the lines above
Some time ago i did a small project called Huygens. The intention was to
demonstrate and evaluate various tools for presenting data. One topic i am presenting on my Wave Optics page some calculated interference pattern. Basically for every point (x,y) on a 2 dimensional the intensity has to be calculated. In SciLab the essential part looks as below. D is the function which calculates the intensity at x,y on the canvas. The complete process of displaying a picture like Fig. 1 are the few lines below:

function result=D(x, y)
result = sqrt(x*x + y*y);
clf ; fgrayplot([-100:100], [-100:100], D);

which is really neat. For more information on grayplot refere to the reference 


There are a few tutorials on youTube which found very help full for the begin!