Archive for category Science

OMNeT++: Error during startup: No user interface (Cmdenv, Tkenv, etc.) found

Posted by on Wednesday, 7 December, 2011

After an update of GCC (on Kubuntu 11.10) this error shows up when running simulations after recompilation.
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PHP Script for Calculating Confidence Intervals

Posted by on Tuesday, 29 November, 2011

Some time ago I wrote about a Shell Script for calculating confidence intervals. Since I also do a lot of number crunching with PHP (hey, it’s web-based and works great with an SQL server for the data!) I wrote a PHP script to get the job done. Here’s how. Read the rest of this entry »

Simulation: event-bounded VS time-bounded termination

Posted by on Tuesday, 29 November, 2011

Doing discrete event (network) simulations; which termination criterion do you use? This article concerns OMNeT++/MiXiM but could easily be generalised. Read the rest of this entry »

Matlab: foreach element in array; do something.

Posted by on Thursday, 27 October, 2011

If you have your data in an array (or matrix for that matter) and want to perform operations on it, most programming languages have foreach statement which lets you easily iterate all values. Matlab, actually, does not differ much. Read the rest of this entry »

Matlab: increasing precision

Posted by on Wednesday, 19 October, 2011

Sometimes Matlab does not always perform as expected. This can be because of the IEEE 754 binary double precision floating point (double) representation used by Matlab: there is a finite number of digits to represent a number and this may not always be enough. We discuss how to use the Symbolic Toolkit to circumvent this. Read the rest of this entry »