Computer Chess Club Archives




Subject: Re: Question: Fail low at root and time management

Author: Robert Hyatt

Date: 14:57:58 02/08/00

Go up one level in this thread

On February 08, 2000 at 14:24:09, William Bryant wrote:

>On February 08, 2000 at 11:41:59, Robert Hyatt wrote:
>>On February 08, 2000 at 10:09:27, William Bryant wrote:
>>>I need some recomendations on handling time management when the program
>>>fails low at the root near the end of the alloted search time.
>>>(During game play, not during test suites)
>>>How do people handle this?
>>>Do you research the PV move at the lower window (which will return a
>>>move and a score) and then stop?
>>I re-search...  but then pay attention to the score.  If the score is more
>>than a pawn lower than the last iteration, I use more time, up to 5x more
>>time in fact.  Hoping that a different ply-1 move will eliminate this loss of
>Thank you for the prompt response.  Let me see if I understand.
>You fail low on the root pv move and stop the search, drop the aspiration window
>and research the root pv move to get a new score.  _If_ this score is
>within 1 pawn of the original score, you stop the search and accept this move.
>_If_ the score drops more than 1 pawn, a potentially dangerous move, then you
>need to try and find a new root pv move and will extend the search up to 5x more
>in terms of time to find a new root pv move and to prevent playing a bad move
>that will wreck the current position.

It isn't done quite that simply.  If the score drops by a pawn, I will spend
a _bunch_ of time trying to fix it.  If the score drops by 1/3 of a pawn, I
will spend a significant amount of time trying to fix that, but not nearly
as much as I would spend saving material.

>Now, with hopefully good move ordering, do you stop after the first non-pv move
>is searched (f the score is good enough on the research), or do you need to
>research all of the root moves at this point before determining the new pv move.

I stop the search when both of the following is true:  (a) I have used the
target time _AND_ the score is acceptable;  (b) I have used more than the
'panic time allocation'  (5x for losing material, 2x for losing positional


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