I am working on a large matrix. It is lower-triangular, meaning that the diagonal entries are 0s, and everything above the diagonal is blank. Each cell below the diagonal has a particular value (numeric).
I want to pick a series of entries, e.g., (row #10, column # 20), (row#25, col#55), (row#105, col#50), and so on ... and save them as a new column.
Right now I am doing this manually. Is there a better and more efficient way to accomplish this?
Thanks.