# Default potential in super-value nodes

Issue #50 resolved Manuel Luque created an issue

[This issue is related with the issue "Range of utility nodes" that was open in org.openmarkov. I've just eliminated it, and the problem is explained here]

I think we discussed this some time ago, but I'd like to clarify the things before the release.

The default potential in super-value nodes in the GUI is Uniform. That creates problems in the inference, because no function is defined for Uniform potentials in super-value nodes. I propose to have default Sum potential in super-value nodes. I suspect that can be difficult to be managed in the GUI, but sum is the implicit operation among utility nodes in influence diagrams without having super-value nodes. We'll therefore being coherent with that.

If we decide that the default potential in super-value nodes is Uniform we then should consider two things: 1. Uniform is not a valid potential in a super-value node. In my opinion, it is not very user-friendly that the program proposes default values in the potentials that are not valid. 2. The inference should return an exception when the user tries to evaluate a network that has invalid potentials.

We can discuss this on the next meeting.

1. We have agreed in today's meeting that initially the potential will be a table (a table of 0 variables is a constant). If the user adds a numerical variable as a parent of this one, the potential will be turned into a sum. If all the numerical parents are removed, the potential will be turned into a table again.

If the parents of a utility node are a mixture of finite state and numeric variables, then the potential will be uniform and the inference algorithms will throw an exception. This behavior will change when we implement LinearCombinationPotential.

2. Resolved. Supervalue nodes now have table potential with zero variables when have only utility parents. When parents are a mixture of numerical variables and and utility nodes then potential is a sum. When parents of supervalue nodes are a mixture of utility nodes, numerical, finite states or discretized, then the potential is uniform.

3. Was resolved when adding a new parent but not when changing domain of a node that has a utility child.

4. • changed status to open
5. Resolved