net$setVirtualEvidence

[nzsk]

I have a hybrid network and would like to set virtual evidence on a discrete node, either a parent or a child. In both cases, the hybrid network gets discretised. Is it possible to set virtual evidence on a discrete parent node in GeNIe without discretising the network? I guess I'm trying to use this functionality as 'soft' evidence - what's the difference?

Many thanks

Miriam

[shooltz[BayesFusion]]

Setting a virtual evidence on a discrete node with no parents will cause discretisation. The implementation of virtual evidence in SMILE creates a temporary child node for each node with virtual evidence. The temporary child node has a 2-state CPT populated with numbers specified for virtual evidence, and evidence is set on a child. This condition (a node with evidence which has one or more parents) requires discretisation.

The theoretical interpretation of the temporary node child is that it provides uncertain information about its parent, which is what virtual evidence is about.

[nzsk]

Many thanks, seems like I will have to use net$setNodeDefinition function for the chance nodes instead to apply the network to a table to cases without discretisation.