Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Interpreting my analysis of the Fine 70 position.

Author: Stuart Cracraft

Date: 19:40:05 07/11/04

Go up one level in this thread


On July 11, 2004 at 15:50:56, Eric Oldre wrote:

>On July 11, 2004 at 15:21:07, Will Singleton wrote:
>
>>On July 11, 2004 at 14:35:50, Eric Oldre wrote:
>>
>>>[D]8/k7/3p4/p2P1p2/P2P1P2/8/8/K7 w - - 0 1
>>>
>>>I ran my engine on the fine 70 position above. which Anthony Cozzie recommended
>>>to me last night as a good position to test for transposition table issues.
>>>below is my new engines analysis of the position.
>>>
>>>(note, I'm not yet sure if I will call it "Murderhole2" or give it a completely
>>>new name)
>>>
>>>Murderhole2 release  WB2 25 MB:
>>> 1   00:00  1.48   a1b1
>>> 2   00:00  1.40   a1b1 a7a8
>>> 3   00:00  1.45   a1b1 a7a8 b1c1
>>> 4   00:00  1.40   a1b1 a7b8 b1c1 b8c8
>>> 5   00:00  1.40   a1b1 a7b8 b1b2 b8c8 b2c1
>>> 6   00:00  1.40   a1b1 a7b8 b1b2 b8b7 b2c1 b7c8
>>> 7   00:00  1.40   a1b1 a7b8 b1b2 b8b7 b2b1 b7c8 b1c1
>>> 8   00:00  1.40   a1b1 a7b8 b1b2 b8b7 b2b1 b7b8 b1c1 c8b8
>>> 9   00:00  1.45   a1b2 a7a8 b2c1 a8b8 c1d2 b8c8 d2c2
>>>10   00:00  1.40   a1b2 a7a8 b2c1 a8b8 c1d2 b8c8 d2c2 c8b7 c2c1 b7c8
>>>11   00:00  1.45   a1a2 a7a6 a2b2 a6b6 b2c3 b6a7 c3d2 a7a8 d2c2 a8b8
>>>12   00:00  1.42   a1a2 a7a6 a2b2 a6b6 b2c3 b6a7 c3d2 a7a8 d2c2 a8b8 c2d2 b8c8
>>>13   00:00  1.47   a1b1 a7b7 b1c1 b7a8 c1d2 a8b8 d2e1 b8b7 e1f1 b7c8 f1g2
>>>14   00:01  1.45   a1b1 a7b7 b1a1 b7c8 a1b2 c8b7 b2b3 b7c7 b3c4 c7b6 c4c3
>>>15   00:02  1.47   a1a2 a7a8 a2b1 a8b8 b1a2 b8c8 a2a3 c8b8 a3b3 b8b7 b3b2
>>>16   00:04  1.45   a1a2 a7b7 a2b2 b7c8 b2c3 c8b7 c3b2 b7c8 b2c3 c8b7 c3b2 b7c8
>>>b2a1 c8c7 c1b1
>>>17   00:08  1.48   a1b1 a7a8 b1c1 a8a7 c1d2 a7b6 d2e2 b6c7 e2f3 c7d8 f3e2
>>>18   00:12  1.58   a1a2 a7a8 a2b2
>>>19   00:35  1.60   a1b1 a7b8 b1c1 b8c8 c1c2 c8c7 c2d3 c7b6 d3e2 b6c7 e2e3 c7d8
>>>e3d3 d8c7
>>>20   01:12  1.62   a1b1 a7b7 b1c1 b7c7 c1b2 c7c8 b2c2 c8b7 a2b2 b8c8 b2c2 c8b7
>>>a2b2 b8c8 b2c2 c8b8 a3b3 b8c7
>>>21   03:51  1.62   a1b1 a7b7 b1c1 b7c7 c1b2 c7c8 b2a2 c8b8 a2a1 b8b7 a1b1 b7a7
>>>b1c1 a7b7
>>>
>>>it does eventually at depth 19 decide on the correct answer of a1b1. however, it
>>>looks like it is simply it trying to avoid the draw by repitition and counts
>>>itself as ahead due to it's extra pawn. it doesn't get a crushing score at this
>>>depth at all.
>>>
>>>at this point the eval function is simply static material and piece/square value
>>>tables, i hope to add more advanced techniques this week.
>>>
>>>I'm looking for some advice in interpreting these results.
>>>
>>>a) did I just not let it search deep enough?
>>>b) does the fact that it took 3:51 to reach depth 21 indictate a issue with my
>>>tranposition table? it was running at 1,200,000 nodes/sec.
>>
>>Yes.  As you probably know from running other programs on this, it should blow
>>thru 21 ply in less than a second.  Do you use two tables or one?  Depth or
>>always replace?
>>
>
>currently i'm using only 1 table, and always replace, thinking more carefully
>that could very well be the cause of the issue, as the useful results may be
>getting thrown away. I'll try and get a two table scheme in place to see if that
>changes my results, or maybe switch to a replace if deeper scheme and see if
>that alone will fix it. (eventually i'll move to a 2 table system either way)
>always replace

Okay -- I ran a longer test. For "always replace" "replace when
>= to hash table depth" and "replace when > hash table depth.
In all cases the result climbed in that direction. The difference
is 6 problems out of 300 which might still be within a margin of
error.

Here are the results for 50 and 300 for each

replce always
*** 78% 39/50 39.28 6815579 136312/1/173499 0/0/244611/00/1046538
*** 48% 145/300 251.04 37886496 126288/1/150919 0/0/1722292/00/5315866

replace if new depth >= hash table entry's depth
*** 80% 40/50 41.59 7046263 140925/1/169414 0/0/241311/00/1040909
*** 49% 147/300 253.43 39100596 130335/1/154285 0/0/1738477/00/5356318

replace if new depth > hash table entry's depth
*** 84% 42/50 41.17 7108063 142161/1/172639 0/0/239152/00/1031626
*** 50% 151/300 249.68 38633064 128777/1/154727 0/0/1735728/00/5305355

Stuart



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.