Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Programming problems with PV

Author: Thorsten Greiner

Date: 04:10:15 05/18/00

Go up one level in this thread


On May 18, 2000 at 06:58:44, Jan Pernicka wrote:

> Hi,
>I have to face this problem:
> When using aspiration search at the root with window <eval-100,eval+100> I
>occasionally get fail high - for example when I have found a mate. Problem
>is when the returned score (let's call it S)is actually the exact value of my
>position - in this case I do a research with window <S,+infinity> but

Research with <S-1, +infinity>. At least that is what crafty does.

In my program I just fetch the PV from the transposition table. Like Diep does
(Hi Vince!).

>I'm unable to set PV properly at that ply - and if it's last ply of the search
>PV is wrong... (e.g. showing PV not leading to mate even though returned score
>says it will be mate...).
>  I set the PV in the tree when:
>    1) I got cutoff
>    2) eval()>alfa
>Thank you in advance for your suggestions.
> Jan



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.