Create an array of the row and column values for the indices of an array.

This is typically performed using [r c]=ind2sub(size(matrix), index).

The ind2sub output can be vectorized.

Create an index row/col array(irc) where index is the row of the irc array, column 1 is the array row and column 2 is the array column.

m=[0 0; 0 1] has four indices thus producing a four row and two column irc array.

 irc=
  [1 1
   2 1
   1 2
   2 2]

Index 4's row is irc(4,1)=2 and its col is irc(4,2)=2. The values of m are irrelevant.

Puzzle, and initial tightest solution, inspired by code implemented by Alfonso Nieto-Castanon.