Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: How many nodes do you need to search 15 plies?

Author: blass uri

Date: 00:04:34 07/22/00

Go up one level in this thread


On July 22, 2000 at 00:41:13, Robert Hyatt wrote:

>On July 22, 2000 at 00:24:39, blass uri wrote:
>
>>On July 22, 2000 at 00:07:18, Robert Hyatt wrote:
>>
>>>On July 21, 2000 at 23:36:51, blass uri wrote:
>>>
>>>>On July 21, 2000 at 23:27:47, Robert Hyatt wrote:
>>>>
>>>><snipped>
>>>>>Here is my numbers, on a quad xeon/550mhz machine.
>>>>>
>>>>>9 plies took 2M nodes
>>>>>10 plies took 5M nodes (this is 5M total from plies 1-10)
>>>>>11 plies took 9M nodes
>>>>>12 plies took 100M nodes
>>>>>13 plies took 500M nodes
>>>>>14 plies took 700M nodes
>>>>>15 plies took 1300M nodes
>>>>>
>>>>>If I could average 200M nodes per second, I could do that search in probably
>>>>>under 5 seconds, given enough memory.  If I could peak at 1B, I could do that
>>>>>search between 1 and 5 seconds somewhere, depending on how the peak went...
>>>>>
>>>>>Note that his 30% efficiency figure is an average as is my 3.2X faster on a
>>>>>quad.  I have many positions where I run 4x faster.  I have a couple where
>>>>>I run 1/10th as fast as one cpu...
>>>>>
>>>>>For me, these numbers should be reduced by at least 25%, which is my search
>>>>>overhead (extra nodes searched that a sequential search would not examine).
>>>>>Hsu's 200M figure already had his overhead factored out...
>>>>>
>>>>>I am not sure what this proves, when you factor in parallel search.  Odd
>>>>>things happen.  Some searches go way fast.  Others go way slow.  Trying to
>>>>>compare searches by comparing depths is not so useful.  In some positions
>>>>>I might extend way too much.   In other positions they might do the same.
>>>>>In other positions we might extend pretty equally. How to know and compare?
>>>>>
>>>>>I could probably search this tree in less than 1/2 the nodes if I had a decent
>>>>>sized hash table.  This grossly overruns anything I can use on this machine
>>>>>tonight...
>>>>
>>>>Did you use recursive null move pruning in this search?(I think you should not
>>>>use null move pruning in order to do the right comparison)
>>>>
>>>>Uri
>>>
>>>
>>>I ran "crafty".  I can turn null off.  or anything else.  But it still doesn't
>>>give us an accurate comparison.  Remember that DB has two parts to the search.
>>>
>>>The first number is the software search, which does _all_ their extension stuff
>>>including singular extensions and whatever.  The second number is their hardware
>>>search which doesn't do singular extensions.  I am pretty sure the hardware does
>>>"out of check" extensions as Belle did and the hardware was patterned after the
>>>Belle machine.  Belle didn't do recapture extensions, so I don't know whether
>>>the DB chip does or not.  The DB hardware does do futility pruning in the q-
>>>search while not everybody does that (I do).  So comparing their 9+6 time to
>>>my 15 time is probably not right.  There 9+6 is probably closer to my 13/14
>>>when you factor in the fact that I can trigger extensions anywhere from ply 1
>>>to ply N, while for them, the last 6 plies trigger fewer extensions in the
>>>hardware.
>>
>>I understood that you claim that they do more extensions than other programs and
>>not less extensions(if they cannot trigger extensions in the last 6 plies
>>then the picture may be different and I may be right that they played c4 against
>>Fritz3 because of lack of extensions).
>>
>>Uri
>
>Note that I didn't say "no extensions" in the last 6 plies.  I said "no singular
>extensions in the last 6 plies".


Crafty also does not do singular extensions and you said that their 15 plies are
close to your 13-14 plies that means that Crafty does more extensions than
Deeper blue inspite of not doing singular extension.

Uri



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.