limited number of iterations - PROLOG

On 2005-08-09, Rainer H <tsubasa@aon.at> wrote:
> Hello everybody,
>
> I have a rule solution(X) which represents an optimization algorithms where
> X returns a possible solution. Since just calling it "solution(X)." returns
> all possible ones which are in size 10^50 I just want the first 100
> results.
> I did it the following way:
>
> finalResult([]).
> count(0, 100).
> getSolution(X) :-
> solution(X),
> checkNewSolution(X),
> count(L, R),
> retract(count(_, _)),
> NewL is L+1,
> assert(count(NewL, R)),
> NewL > R,
> !.
>
> checkNewSolution(X) checks if the current solution is better than the one in
> finalResult(X) and replaces it.
>
> That did work, but now I have the problem that I am running this prolog
> application within an environment (P# in .NET) where I cannot use the
> assert and retract rules.
>
> Is there any other way?

You will need some form of non-backtrackable data. Can be assert/retract,
record/recorded, global variables, non-backtrackable destructive assignment
on arguments of compounds and maybe more. If P# doesn't have any of these
I think it is time to look for another Prolog.

Cheers --- Jan