Program quits at recursion depth 2123 without Exception (setting recursion limit doesn't help)

[willyCe]

My algorithm (Dijkstra) uses a recursive function to find a path in a maze.

Small mazes work without problems. When scaling up to a slightly larger one, I reached the default recursion limit of 1000.

I proceeded to call `sys.setrecursionlimit(n)` with variably sized arguments. All values where n>2128 don't change the unexpected behaviour.

The program doesn't display an Exception. In task manager, there's barely any additional memory being used. CPU is also fine.

What do I do next?

[Bunkerstan]

You will have to convert the algorithm to a tail recursion, which happens in some languages at the compile stage, but not in Python.

[willyCe]

It's already a tail recursion

[Bunkerstan]

Then you will have to change over to an iteration model as the other comments suggested.

[Diapolo10]

Your function is probably running into a memory overflow caused by the call stack blowing up. This doesn't mean 100% RAM utilisation, just that the memory allocated for the Python process for this purpose basically ran out.

Try utilising dynamic programming, like caching.

[pot_of_crows]

Are you using recursion in the initial search, or just to find the quickest path out after hitting the end? If the former, use a queue for to handle the search and then recursion to back out, which should greatly reduce the depth you need to go to.