Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Does Hydra try to avoid a second Leiden?

Author: Robert C Gates

Date: 13:39:29 05/19/04

Go up one level in this thread


On May 19, 2004 at 10:51:41, Vincent Diepeveen wrote:

>On May 19, 2004 at 10:18:01, Ingo Althofer wrote:
>
>>In the Leiden tournament (in April 2004) Hydra was terribly bashed by Shredder.
>>Perhaps after that they only play in events without Shredder.  ;)
>>
>>Ingo Althofer.
>
>I feel we must not be too hard judging the hydra team. It's the sheikh who
>doesn't want to join in Israel. I'm sure the entire team wants to.
>
>However any claim that Hydra is the strongest chess program on earth must be
>forgotten. It was very lucky in Leiden in many games. I'm sure the quick level
>of 90 0 and majority of participants not using big hardware has lead to Hydra
>scoring more points than it based upon what it showed earned IMHO.
>
>Basically the ultra agressive speculative evaluation which Hydra uses to play
>means it will never win a world title. Ultra agressive behaviour has 2
>advantages :
>  a) you kill every bad tested program with big bugs left in eval (especially
>king safety) thanks to agressive attack and big search depth.
>  b) it has a nice playing style. attack attack without looking back...
>
>It has 1 major disadvantage:
>  a) it is incorrect and will simply lose in future
>
>Note that there is a subtle but important difference between agressive play and
>speculative agressive play.
>
>So time is running out slowly for Hydra now. 1 chip is not so slow now compared
>to software, but next year it will be when the dual opterons at 1 chip start to
>arrive.
>
>The software guys all will profit from hashtables a lot at opteron and each
>generation getting faster we profit a lot.
>
>Hardware however doesn't profit from all that. Last 6 plies no hashtables for
>Hydra...
>
>Hydra's parallel search doesn't scale to more processors easily when compared to
>software using a hashtable. Moving from 8 to 16 processors i didn't see it
>search deeper actually (i forgot to ask during ict4 how many processors used,
>frankly i didn't care at that moment).
>
>So in 2010 they probably will be still 16 processor clocked at 33Mhz.
>
>Perhaps one time an update to 66Mhz and PCI-X myrinet cards (3 us one way ping
>pong latency versus the current ones it has are like 8 us).
>
>So in 2004 world champs the hardware advantage from hydra would be not there,
>but in 2005 for sure also gone against many non-world champs participants.
>
>What is left is a strong program definitely in world top and of course eyes
>closed crushes software like crafty (even when using just 1 hardware processor,

 What do you mean Crushes programs Like Crafty? Crafty is one of the Best
around.






>because eval just matters).
>
>However it is outdated right now IMHO.
>
>It's advantage IMHO was using 8-16 processors, not for being in hardware.
>
>And knowing the parallel skills of the university paderborn (feldman & co)
>adding more processors we can only expect a slowdown.
>
>When running at 460 processors with diep i did several experiments turning off
>hashtable last few plies and had very discouraging results there.
>
>Note that Feldmann correctly had already concluded this years ago (that one
>*needs* to do hashtable lookups everywhere; for me it is amazing that Feldmann
>could draw so many correct conclusions with such bad software implementations).



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.