This is a dirty solution, but it might be interesting: It is possible to implement "tail recursion"; this would solve the problem for certain kinds of recursion; but will fail if the call is not a tail call, and I think this code won't work, but some variations would...
I toss it as an idea: The code is taken from http://code.activestate.com/recipes/474088 import sys class TailRecurseException: def __init__(self, args, kwargs): self.args = args self.kwargs = kwargs def tail_call_optimized(g): """ This function decorates a function with tail call optimization. It does this by throwing an exception if it is it's own grandparent, and catching such exceptions to fake the tail call optimization. This function fails if the decorated function recurses in a non-tail context. """ def func(*args, **kwargs): f = sys._getframe() if f.f_back and f.f_back.f_back \ and f.f_back.f_back.f_code == f.f_code: raise TailRecurseException(args, kwargs) else: while 1: try: return g(*args, **kwargs) except TailRecurseException, e: args = e.args kwargs = e.kwargs func.__doc__ = g.__doc__ return func @tail_call_optimized def factorial(n, acc=1): "calculate a factorial" if n == 0: return acc return factorial(n-1, n*acc) print factorial(10000) prints a big, big number, but doesn't hit the recursion limit. @tail_call_optimized def fib(i, current = 0, next = 1): if i == 0: return current else: return fib(i - 1, next, current + next) print fib(10000) also prints a big number, but doesn't hit the recursion limit. @tail_call_optimized def say(something): print something say(something) say('hello') If I remember correctly, this code breaks and hangs the computer if the tail is not a tail call; but there seems to be other solutions in http://code.activestate.com/recipes/474088 that solve this problem I would love if sage included a similar decorator; but am not sure of the implications. Another alternative is rewriting your code... to use iterations instead of recursion whenever possible. Peace. -Adri'an. On Mar 26, 6:24 am, agi <agnes.j...@googlemail.com> wrote: > Hi, > I have a recursive algorithm that works well if it doesn't need more > than 5637 iterations. > In the case of more than 5637 iterations the error message is: > RuntimeError: maximum recursion depth exceeded in cmp > > Is there a way to make SAGE execute it for more than 5637 iterations? --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
