I have posted a question on here before regarding the generation of a number sequence. I followed up that question with an answer. However, as I have developed my code more I need to use an equation instead of a lookup table. Note: I'm using MATLAB Given a matrix A of size r x c where r >= 3, c >= 3 I need to map the center point of a 3 x 3 raster segment to a point in A. The raster segments go from left to right, top to bottom. For example, if Code (Text): A = [0 1 1 0 1 0 1 0 1;... 0 0 1 0 0 1 1 0 1;... 1 0 1 1 0 1 0 1 0;... 1 1 1 1 1 1 1 1 1];... The location of (2,2) in each raster segment can be found as follows. Code (Text): %raster binary image matrix into 3x3 segments M = im2col(FP, [3,3],'sliding'); [ri ci] = size(A); [rM cM] = size(M); %Generate table of locations in binary image matrix for center point (2,2) of segment matrices rownums = repmat([2:ri-1],cM/(ri-2),1); rownums = rownums(:); colnums = repmat([2:ci-1]',1,cM/(ci-2)); colnums = colnums(:); locations = [rownums,colnums] I only need matrix M to find what rM and cM are. Instead of using the im2col() function, I can use the equations below. cM is the number of total raster segments Code (Text): rM = 9; cM = (ci-2)*(ri-2); I do some matrix operations for each raster segment using a for loop Code (Text): n = 1; k = 1; for row = 1:ri-2 for col = 1:ci-2 %some operations if %condition is met %transform center point location in raster segment %to corresponding location in matrix A Iloc(n,:) = locations(k,:); n = n+1; end else %if condition is not met, increment segment counter k and continue %in for loop to next segment k = k+1; continue end k = k+1; end end I would like to replace this line of code Code (Text): Iloc(n,:) = locations(k,:); with equations for the row and column location in A instead of looking up in the table for these locations. The reason for this is that if I have a matrix A of size 274 x 234, I would have 63104 raster segments. This means that my location table matrix would be 63104 x 2. This takes up a lot of memory with the other stuff that I am doing. I know it's possible to come up with some equation that's dependent on the value of row, col, and k. It seems that every (ci-2) kth value, the row in A increments by one. For every different row value, the column values go from 2:(ci-1). Question is how do I activate the row increment and column range for every (ci-2) kth value?