Error in multiplicationDirectiveTile

[jbouffard]

There is a chance for multiplicationDirectiveTile to fail in certain cases due to this line:

maml/jvm/src/main/scala/eval/directive/OpDirectives.scala

Line 116 in 02f5c9f

val scalarSum: Double = dbls.reduce(_ * _) + ints.reduce(_ * _)

The reason why this would be fail is that it is not possible to reduce an empty collection in Scala, so if either dbls or ints is empty then the method will fail.