Author: Omid David
Date: 06:15:12 06/01/02
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The question was an algorithmic one: How to escape a full window search of
(-10000,10000) at any cost. In theory this shouldn't occur since after the
following steps:
best = negascout(alpha, beta, depth);
/* re-search */
if(best <= alpha)
best = AlphaBeta(-10000, beta, depth);
else if(best >= beta)
best = AlphaBeta(alpha, 10000, depth);
The value should be between the alpha-beta bound. However in practice sometimes
it happens that after the re-search the result is still out of the bound. The
frequency of this depends on the evaluation function. While Genesis faces this
problem very rarely, other programs with simpler eval functions will more
frequently have to deal with the problem above.
In none of the open-source programs I found an algorithmic solution to the
problem. Maybe this is the way it has to be!
And, thanks Dann for all the code you posted, it saved me hours of navigation in
different programs' codes!
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