Value * is not a member of AnyVal - scala

Question

This is a fold that I wrote and I get this error:
Error:(26, 42) value * is not a member of AnyVal
(candE.intersect(candR), massE * massR)
^
allAssignmentsTable is a List[Map[Set[Candidate[A]],Double]]
val allAssignmentsTable = hypothesis.map(h => {
allAssignments.map(copySet => {
if(h.getAssignment.keySet.contains(copySet))
(copySet -> h.getAssignment(copySet))
else
(copySet -> 0.0)
}).toMap
})
val aggregated = allAssignmentsTable.foldLeft(initialFold) { (res,element) =>
val allIntersects = element.map {
case (candE, massE) =>
res.map {
case (candR, massR) => candE.intersect(candR), massE * massR
}.toList
}.toList.flatten
val normalizer = allIntersects.groupBy(_._1).filter(_._1.size == 0).map {
case(key, value) => value.foldLeft(0.0)((e,i) => i._2 + e)
}.head
allIntersects.groupBy(_._1).map {
case(key, value) => key -> value.foldLeft(0.0)((e,i) => i._2 + e)
}
}
if I do this: case(candE, massE:Double) then I won't get an error but I will get exception in match.

Answer 1

The problem that you get here:
val aggregated = allAssignmentsTable.foldLeft(initialFold) { (res,element) =>
val allIntersects = element.map {
case (candE, massE) =>
res.map {
case (candR, massR) => candE.intersect(candR), massE * massR
}.toList
}.toList.flatten
is most probably arising from the previous code block:
val allAssignmentsTable = hypothesis.map(h => {
allAssignments.map(copySet => {
if(h.getAssignment.keySet.contains(copySet))
(copySet -> h.getAssignment(copySet))
else
(copySet -> 0.0)
}).toMap
})
My hypothesis is that h.getAssignment(copySet) returns something else instead of Double (which seems to be confirmed by the error message quoted in the OP - (26, 42)etc, neither of these two values look like it is a Double. Therefore, allAssignmentsTable undercover is probably not List[Map[Set[Candidate[A]],Double]] but something else e.g. it has Any instead of Double, therefore operator * cannot be applied.