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Subject: Re: Some PV thoughts...

Author: Bo Persson

Date: 03:22:45 11/25/00

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On November 24, 2000 at 03:17:28, Severi Salminen wrote:

>On November 23, 2000 at 17:43:57, Pham Minh Tri wrote:
>
>>On November 23, 2000 at 08:46:36, Severi Salminen wrote:
>>
>>>Hi!
>>>
>>>I managed to get my Principal Variation working. Now I have a simple AB search,
>>>with iterative deepening and I'm trying to search first the PV moves from last
>>>iteration. The strange thing is that I get very little savings in node count
>>>when activating the PV sorting. Could the reason be that 1. I evaluate only
>>>material and allready have captures tried first. 2.When I place the PV move in
>>>front of the queue I place one capturing move further away. I also don't have
>>>qsearch yet. How much should "normally" the total node count decrease when I try
>>>PV moves first in every ply?
>>>
>>>Severi
>>
>>I have seen the same situation in my program. However, I always try the best
>>moves from hash table first, and those moves are very similar to pv moves. If
>>you have not hash table, something should be wrong. The easiest way to
>>experiment, download the TSCP and turn off its pv - the number of nodes will
>>increase notabbly.
>
>No, I don't have hash tables yet. But I added some basic square_table evaluation
> and this helped...maybe, as I can't test right now. I also added Qsearch...man,
>this is interesting! Do you happen to know how SEE actually works? Should I just
>take one square which is attacked more than once and calculate the outcome
>statically?

Yes, but it is sort of semi-static.

For example, if a bishop attacks the sqaure, there might be a queen behind the
bishop. The queen isn't attacking the square until *after* the bishop has made
its capture.



>Severi

Bo Persson
bop@malmo.mail.telia.com



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