Sunday, 28 June 2009

A General Purpose Network Solver?

I often get frustrated if I want to solve a simple fluid flow or thermal problem that is in the form of a network with branches, parallel paths etc. These tend to be a bit to difficult for a "back of the envelope" solution, which is always my preferred approach, so you end up writing code to iterate to find solution.

The easy way would be to use a commercial package like Aspen Hysis, SINDA or ESATAN, but these are very expensive for the once a year or thereabouts that I need to solve something like this. It would be nice to have a simple, low cost solver available.

I thought there would be plenty of open source ones available, but I have not been able to find a simple network solver, so I am going to resort to writing it myself. I did do one once before, but I seem to have lost the source code....It never got finished properly anyway.

I have started the project at http://code.google.com/p/openproc. There is no code worth talking of there yet, but the Wiki describes the sort of design I am thinking of. Any offers of help greatly appreciated!

Tuesday, 9 June 2009

More Ubuntu 9.04 Sound Problems

I 'accidentally' wrecked my gnome desktop (no menus, toolabrs etc.) - I had been doing a bit of tidying up and must have uninstalled something important. I could not decide what, so re-installed the whole ubuntu-desktop package.
This came with pulseaudio again, so sound stopped working like last time.
Decided to invest an hour in sorting it. No real success searching on the web, but I did find this article - http://ubuntuforums.org/showthread.php?t=962695. The author provided a little script to update the ALSA drivers automatically, and quite a few people reported that this cured the sound for them.

I am always wary about running unknown programs as root, but the script looked safe enough - just an automated way of downloading the ALSA source packages and running 'make install' etc. so I trusted it.
It ran and it installed ALSA 1.0.20, compared to version 1.0.18 in the Ubuntu package.
To my surprise, when I re-booted the computer, sound is back!