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Subject: Re: Computers are stronger at defense than attack! Humans-not.

Author: Robert Hyatt

Date: 05:19:56 07/20/00

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On July 20, 2000 at 02:37:07, blass uri wrote:

>On July 19, 2000 at 23:42:46, Robert Hyatt wrote:
>
>>On July 18, 2000 at 14:29:53, blass uri wrote:
>>
>>>On July 18, 2000 at 14:27:58, stuart taylor wrote:
>>>
>>>>On July 18, 2000 at 12:17:57, blass uri wrote:
>>>>
>>>>>On July 18, 2000 at 12:10:57, stuart taylor wrote:
>>>>>
>>>>>>Let me clarify. Of course computers always look for the best move in attack, and
>>>>>>also play the move they evaluate as as best. But when they see the evaluation
>>>>>>going down, they will look perhaps a whole extra ply deeper in search of finding
>>>>>>a way to bring the evaluation back up again.
>>>>>>  But if they see their evaluation going up, they do that move, sometimes very
>>>>>>quickly, atleast they don't grind away labouriously trying to find something
>>>>>>even better, even if the first "good move" is not all that good relatively.
>>>>>
>>>>>My knowledge is that Junior almost always finish the iteration of moves.
>>>>>
>>>>>If it see the evaluation goes up it will usually not play without checking all
>>>>>the other moves in the same iteration.
>>>>>
>>>>>Uri
>>>>
>>>>Hiarcs too, usually. But if it is losing, it just goes on and on thinking, for
>>>>very long periods, letting its clock tick till quite near the end.
>>>> If that would help it salvage the position, it would be time well spent.
>>>
>>>Hiarcs is the only program that I know that does it.
>>>
>>>Uri
>>
>>Crafty will do it also...
>
>I meant to the fact that hiarcs does not finish the iteration of moves when it
>fails low but does another iteration.
>


That has _got_ to be wrong.  Why on earth would anyone write a search that
would fail low, and then start a new iteration (that it might not have a chance
of searching even the first move on) without first checking all of the remaining
moves at this iteration to see if one will bring the score back up?

I can't imagine any reason to do that...  valid or invalid...




>I claimed that Junior usually finish the iteration of moves before playing.
>
>stuart replied
>Hiarcs too but if it is losing it just goes on thinking...
>
>He meant that finising the iteration of moves is not enough after failing low
>and it does another iteration.
>
>I replied that hiarcs is the only program that I know that does it.
>
>My opinion is that the idea of doing another iteration after failing low may be
>a good idea only when you have many moves to the time control.

I would say it is senseless, period, if you don't first finish the _current_
iteration.  Starting a new iteration with no clue about the best move is a good
way to burn lots of cpu time and get nothing back.  If Hiarcs does that, I'd bet
it is a bug.




>
>If you have 110 minutes for moves 15-40 and you fail low then using 30 minutes
>for one move because of doing another iteration is not a disaster and may be
>productive but later in the game it is not a good idea.
>
>Uri


This depends.  If you have 45 minutes to make 5 moves, and you use 30 minutes to
avoid losing a piece, it makes sense.  As the extra time is of no use if you are
essentially lost...



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