So I\'m trying to use the octave debugger to detect where division by zero happens. For that it seems logical to use \"debug_on_warning ()\". However I\'m just not understan
Take a look at the Debugging section of the Octave manual.
For your case, you should place debug_on_warning (1) at the top of your script so it stops when the warning happens and drops you in debug mode. Then type dbwhere to find out where you are.
An alternative, that's the way I do it, leave the command keyboard in certain areas where you think the problem may be. Then use dbstep to evaluate your script line by line.