Author Topic: Does HUGIN support constraints in structure learning?  (Read 7626 times)

Offline Anders L Madsen

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Does HUGIN support constraints in structure learning?
« on: January 18, 2011, 16:13:39 »
Yes, the HUGIN GUI allows the user to save and load structural constraints between nodes in a file. Structure constraints can be saved in and loaded from a file in the “Structure Constraints”-step of the Learning Wizard. You use the “save network with constraints” button to save structure constraints in a network specification file and the “import model information” button to load constraints from a network specification file.

For instance, if you want to disallow a certain direction on a link, then you would use the “No Arrow Constraint Tool” to define a constraint that a node X is not allowed to be parent of node Y. You can add multiple constraints in one operation by selecting a set of nodes and pressing the right mouse button on another node.

The constraints are saved in a HUGIN .net file. This file can be loaded into the “Structure Constraints”-step of the Learning Wizard. The constraints are defined as attributes on nodes in the .net file. For instance, the “HR_Constraint_X” attribute of this node definition of node D in a .net file:

node D
{
    label = "D";
    position = (210 110);
    states = ("yes" "no");
    HR_Constraint_X = "NoArrow";
}

Specifies that node D is not allowed to be a parent of X.
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