Program: Scilab by INRIA
Liscence: Open source
Description: This is the freeware counterpart of Matlab by Mathworks. Most of the commands in Scilab are similar to those in Matlab, the only downside I've encountered so far is Scilab has lower stack memory. But what the heck, it's free! Its the thing we use in our Digital Signal Processing and Image Processing Courses, and it works fine. It would be great to have it in the portableapps.com format.
Website: www.scilab.org
Others: I've tried coping the installation files to my flash drive and it worked. But when I'm finished using it and try to safely remove my flash drive, there's an error message saying that it cannot be removed at that moment. I can't think of any reason for that, i think it's due to running Scilab from my drive.