Sets the element idx from the map to value. The invoking map should be of only one dimension. Example with a Map of int: M[i in 1..5][j in 1..2] = j M.getSub(1).set(2, 4) will set M[1][2] to 4 instead of 2.

void Set(
	int index,
	IPiecewiseFunctionExpr v
)