I found on www.dspguru.com the following text:

Matlab™ has become the de facto standard for DSP (I add any) system design and simulation. However, Matlab has two problems: 1) it's expensive, and 2) it costs a lot. Fortunately, there are alternatives: Free Clones. Whatever else you can say about them, these Free Clones offer two significant advantages: 1) you don't have to pay for them, and 2) they're free.
In some ways, Scilab may be the "best" of the Matlab clones. Scilab has many strengths, including excellent documentation (the signal processing manual is an education in itself!) and excellent support (via e-mail and its own newsgroup). Best of all, for Windows users, Scilab is supplied not only as source code, but as a Windows binary. Scilab is mostly--but not completely--compatible with Matlab. (Scilab now comes with a Matlab-to-Scilab translator, but that's still a bit immature.) For more information:

Scilab Home Page
http://www-rocq.inria.fr/scilab/scilab.html


I tried and I guess It is a better choice to use this excellent tools instead of VB...
The filling as same as Matlab...

G.