I have an m by n matrix and I'm interested in the nth column. Initially all of the values in the nth column are greater than zero. As the code executes, at some point, a specific row in the nth column will equal zero. I want to determine which row that is. One issue is that after this first instance of zero, all of the subsequent rows in the nth column will also equal zero. I just want the first row in the last column that has a value of zero.