### Author Topic: Using new Function Node  (Read 8937 times)

#### andersrm

• Newbie
• • Posts: 19 ##### Using new Function Node
« on: February 23, 2013, 03:44:06 »
I would like to compute a utility based on the difference between two discrete chance interval nodes.  My understanding is that this CANNOT be done with real-valued function nodes at present since these cannot accept interval nodes as parents.  Any other suggestions on how to do this?  Other than representing the difference as a discrete chance interval node and assigning a discrete utility to each of its states..  Even if I could use a function node, and wanted to assign a utility node as a child, that utility node I suppose could only handle discrete values...

#### Anders L Madsen

• HUGIN Expert
• Hero Member
•     • Posts: 2288 ##### Re: Using new Function Node
« Reply #1 on: February 28, 2013, 19:35:45 »
It is correct that the value of a function node cannot be computed from an interval nodes. The states of an interval nodes represents a range of values and it is not possible to compute the value of a child function node.

In principle, you could add a utility node as the common child and define an expression for its table as the difference between the two parents. Alternatively, you could as a rough approximation add a numbered node as child of the interval nodes and use a function node to compute the difference between the numbered nodes.
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