[Python-ideas] FW: Idea: Compressing the stack on the fly

[Joshua Landau]

On 12 September 2013 09:21, Chris Angelico <rosuav at gmail.com> wrote:
> On Thu, Sep 12, 2013 at 5:03 PM, Joshua Landau <joshua at landau.ws> wrote:
>> On 12 September 2013 07:59, M.-A. Lemburg <mal at egenix.com> wrote:
>>> On 12.09.2013 06:29, Joshua Landau wrote:
>>>> Does anyone actually write recursive Python code where the recursion
>>>> in a significant bottleneck? The only such code I can think of is
>>>> either for a tree, in which case stack depth is irrelevant, or bad
>>>> code.
>>>
>>> Any kind of backtracking algorithm will need recursion or a separate
>>> stack data structure to keep track of the various decisions made
>>> up to a certain point on the path.
>>>
>>> The C stack is rather limited in size, so a recursive parser can
>>> easily blow up if it uses the C stack alone for managing
>>> backtracking.
>>
>> What sort of algorithm would backtrack that many times? I doubt a
>> parser would and I can't think of anything worse ATM.
>
> Solve chess.

If you're managing to simulate more than 1000 moves ahead either
you're doing depth first or you've got a *blisteringly* fast computer.