addSolutionToConstraintData is an internal function for
counting the number of items in a solution that match a constraint.
addSolutionToConstraintData(x, attrib, item_idx, all_values)addSolutionToConstraintData returns an updated data.frame.
a data.frame containing a single constraint data.
an item_attrib object.
item indices in the solution.
for set-based assembly,
TRUE returns all values for each set,
FALSE returns descriptive statisistics.