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Subject: Re: mate threat extension/null move

Author: Michael Henderson

Date: 12:03:58 10/07/04

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On October 07, 2004 at 14:49:29, Michael Henderson wrote:

>On October 05, 2004 at 18:41:58, Stuart Cracraft wrote:
>>On October 04, 2004 at 20:23:27, Don Beal wrote:
>>>Hmmm.  It's very helpful to post the actual code.
>>>My time is limited though.
>>No problem -- you've made good comments and de-lurked
>>and everyone enjoys that.
>>The bet was to decrease the WAC #141 problem down to <= 10
>>seconds without turning off the null move as one
>>claimant had done.
>>Although I am now at 49 seconds for WAC 141 solution with
>>null move enabled and not limited compared to the earlier 95
>>seconds, the <= 10 bet is still open. I'll hereby double the
>>bet to $100 to the first person who helps me achieve it directly.
>Hi Stuart,
>How do you handle mate scores (probe/store) in the hash table?  That is a tricky
>concept sometimes and can lead to bugs :) Also, if you use "bounded" mate scores
>in the hash table your scores will not be exact.  Exact mate scores are
>necessary for the mate threat detection.

in fact, try not storing *any* mate scores in the hash table (check if within
mate score range when storing).  For example, if (val >= MATE-500) don't store
or if (val <= -MATE+500) don't store.  If you can solve WAC in good time with
this then the hash tables are to blame.

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