code: function(fn) {
                  var els = [], i = this.elements.length, nj = this.elements[0].length, j;
              	while (i--) { j = nj;
              		      els[i] = [];
              		      while (j--) {
              			  els[i][j] = fn(this.elements[i][j], i + 1, j + 1);
              		      }
              		    }
              	return Matrix$b.create(els);
                  }
docs: Maps the matrix to another matrix (of the same dimensions) according to the given function