Returns a matrix of integers indicating the number of their slice in a given array.
an array. If
an integer giving the dimension number to slice by.
An integer array
y with dimensions corresponding to those of
x such that all elements of slice number
i with respect
MARGIN have value
col for determining row and column
indexes; in fact, these are special cases of
MARGIN equal to 1 and 2, respectively when
is a matrix.