Dec 162011
 

An odd creature

Here it is. A modern browser will be required.

I’m not sure what it is. It looks nice, but strange.

Technical details:

I used processing to create it and then processing.js to put it on a web page. It’s driven by a system of ODEs based on a particle/spring system with oscillating spring lengths and “magnetic walls”. A common fourth-order Runge–Kutta method is used to solve the ODEs.

 Posted by at 12:07 pm
Dec 082011
 

This is a very quick post describing how to fix an annoyance with Matlab under Linux. I thought I’d share this with the internet to hopefully save the next person who has this trouble some time.

On Linux Matlab R2011b annoyingly requires the fairly old gcc 4.3.4 to compile C/C++ “mex” functions. This is a problem for recent versions of Ubuntu 64-bit. If you attempt to use a more recent version of gcc you get errors like “libstdc++.so.6: version `GLIBCXX_3.4.11′ not found” when trying to run the mex files. This is because matlab uses it’s own libc/stdc++, and only includes them for older compilers.

The fix is to install gcc 3.4 and point matlab to it by editing mexopts.sh. Annoyingly there is no package for gcc 3.4 on Ubuntu 11.10, so you have to build it yourself. The reason for this blog post is that the build isn’t quite “textbook” and it took me a while to get it to work. Hopefully this guide might save some googleing soul the hassle, and I’ll be able to point co-workers to it when they upgrade.

Continue reading »

 Posted by at 2:41 pm