forum.hugin.com
User Forums => HUGIN GUI Discussion => Topic started by: lauchlin on July 16, 2012, 04:03:06

I'm in the process of converting a Netica model in to a OOBN and have been rewriting the Netica formulas to Hugin expressions. The problem I am running in to is that Netica and Hugin handle Normal distributions differently. With Netica if you have a continuous nature node that has been discretized in to two intervals (e.g. 02 and 215) you can use Netica's NormalDist function to define a distribution across the bounded range. Hugin on the other hand expects interval nodes to have a range of +/ infinity. To get around this I have created two extra ranges inf0 and 15+inf and then created a child node that squashes the distribution using Distribution(0,1) and Distribution(1,0) back in to the two ranges effectively dumping everything less than 0 in to the 02 range and everything more than 15 in to the 215 range. This ends up with the correct mean but the variance is out which is no good. In the end it is a hack that only partially works and what I would really like to know is, what is the best way to use Normal distributions with interval nodes in the case that you have a node that represents a real world system that is bounded?

You can use the "truncate" operator to handle this case. See Example 5.1 in the Hugin API Reference Manual.

Thanks. That is exactly the function I should have been looking for.