Method sum returns null Intervention from two potentials with non-null Interventions

[Manuel Luque]

When evaluating the network attached to this issue, the method sum(List<TablePotential> tablePotentials) from DiscretePotentialOperations takes two input TablePotentials as arguments that both have not-null Interventions. The method "sum" returns a result with null Intervention.

[Manuel Luque]

I attached now a more appropriate network to reproduce the bug. You just have to add breakpoints at the beginning and at the end of the method sum in DiscretePotentialOperations.

[Manuel Luque]

The related JUnit test testIDTwoIndependentDecisions() has been added to the class org.openmarkov.inference.InferenceAlgorithmIDTest.