Quote Originally Posted by Jon12345
Sorry guys, I made a mistake. What I thought was the program hanging was in fact a huge slowdown that happens when the numbers get larger. It seems to be a disproportionate slowdown. Consequently, I will have to change the main routine.

leinad31, thank you for the coding you did. I tried to get it working but couldn't. Are you storing the data in a text file or something as opposed to the Textboxes?
Yes I'm using text files... it doesn't matter if its originally in a text file or a textbox... what's important is transfering the list to single dimension string arrays (eg. sA(), sB(), sC()... if there's no data then redim array to ubound zero such as ReDim sA(0)... sA(0) would contain "" by deault)...

post #36 explains how you can generate a particular combination based on these source arrays. Note that the source arrays are not resized unlike in post #34, you just get relevant elements from the sources... you could then transfer to one huge ReDim destination_Array(idxUB), rather than three huge cause of resize source arrays.

post #34 created the combinations per column... I reused the source arrays by resizing them to the number of combinations (ReDim Preserve sA(idxUB))... I then updated "" values in array by copying elements from portion of array with values (from array index 0 to cntA - 1), hence the decrement loops.