Practical tips debugging deep recursion?

Question

I\'m working on a board game algorithm where a large tree is traversed using recursion, however, it\'s not behaving as expected. How do I handle this and what are you experience

Answer 1

I would start by instrumenting the function(s). At each recursive call log the data structures and any other info that will be useful in helping you identify the problem.

Print out the dump along with the source code then get away from the computer and have a nice paper-based debugging session over a cup of coffee.

Answer 2

I once had a similar problem when I was developing an AI algorithm to play a Tetris game. After trying many things a loosing a LOT of hours in reading my own logs and debugging and stepping in and out of functions what worked out for me was to code a fast visualizer and test my code with FIXED input.

So, if time is not a problem and you really want to understand what is going on, get a fixed board state and SEE what your program is doing with the data using a mix of debug logs/output and some sort of your own tools that shows information on each step.

Once you find a board state that gives you this problem, try to pin-point the function(s) where it starts and then you will be in a position to fix it.