computes subtotals and stuff replaces every Dim(last) subgrid by all the results of cascading the operator on that subgrid, producing a Dim(dims, last) grid. For example, with base value 0 and operation + on grid "2 3 5 7" will compute 0+2=2, 2+3=5, 5+5=10, 10+7=17, and give the subtotals "2 5 10 17". [#scan +] computes subtotals ; this can be used, for example, to convert a regular probability distribution into a cumulative one. (or in general, discrete integration) the initial value for the scanning. (default: none) this can be a grid of any size, and this decides the size of the subgrids we are working on: a seed that has N dimensions will cause the scanning to happen on the dimension that is just before the last N dimensions. replaces every subgrid the result (of one or more dimensions) by the partial results of a cascade on that subgrid. [#scan +] on grid "2 3 5 7" does 0+2=2, 2+3=5, 5+5=10, 10+7=17, thus will produce grid "2 5 10 17". Outputs a grid of the same size as the input. numop2: the operator to scan with.