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Subject: Re: Internal Iterative Deepening

Author: Bas Hamstra

Date: 11:06:39 07/25/02

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>>>IID is not a huge thing.  It mainly helps where you fail high but can't get
>>>a real score so that the next iteration, you end up with no hash moves for
>>>the PV search...  IID will supply good moves.
>>
>>All you get is a reasonable move from a D-2 search. Why not store the original
>>hashmove in stead?
>
>Where would you get it from?  I use the fact that there is no hash move
>for a PV node to trigger the IID search...

>>So when you normally store a UPPER score, in stead of saving
>>no move at all, you save the original hashmove? I don't see why IID would
>>provide a better move than that...
>
>Because at the _next_ ply in the tree, you have no move because it is a
>fail low position...

I don't understand. In case of a fail-low position I store the *original*
hashmove which was a bestmove. So, I never am without hashmove.

>Also, you assume that you already have a hash entry with a best move.  But
>that is not a certainty...  So if you don't have one, you can't "save it"
>with your trick.  IID is simply a solution for this that is trivial to
>implement....

Yes, that is correct, there is not always an original hashmove. In particular
the last few plies, where it is least important, this can be the case. I tried
both IID and this, and for the moment I like this better.

Best regards,
Bas.









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