Author: Vincent Diepeveen
Date: 01:56:53 05/07/01
Go up one level in this thread
On May 07, 2001 at 03:19:05, Uri Blass wrote:
>On May 06, 2001 at 23:53:59, Robert Hyatt wrote:
>
>>On May 06, 2001 at 19:46:43, Vincent Diepeveen wrote:
>>
>>>On May 06, 2001 at 02:28:14, Uri Blass wrote:
>>>
>>>>I gave Deep Fritz to analyze similiar number of nodes to Deeper blue and Deep
>>>>Fritz seems to be clearly better in tactics.
>>>>
>>>>Deep Fritz needs only 191728 knodes to see the line Rf5+ Ke3
>>>>It means only 1 second if I asuume 200,000,000 nodes per second.
>>>>
>>>>I believe that Rf5+ failed low at depth 17 for Deeper blue for the reason Ke3.
>>>>The pv of deeper blue at smaller depthes is Rf5+ Ke2
>>>
>>>11 ply for those who are good in math and a bit more real to the world.
>>
>>Uri is correct. Unless you _still_ dispute the direct statement(s) by the
>>Deep Blue team.
>>
>>
>>
>>>
>>>>Deep Fritz probably does better extensions than Deeper blue because Deep Fritz
>>>>see big fail low at depth 16.
>>>
>>>Fritz hardly has dangerous extensions.
>>>
>>>Diep has. note i am not extending passers much. Just a bit and only
>>>now and then.
>>>
>>>The Big fail low comes at 12 ply for DIEP. Then it sees Rf5 is losing
>>>because of Ke3 though it initially wants to go e3. Then i did a state
>>>check to see what the deepest search lines are. You can see it
>>>yourself:
>>
>>
>>What does any of this matter? Their score was bad... yours is bad, black
>>is lost... I don't see where you see it any faster than they did...
>
>I see that Deeper blue score is clearly better than the score of other programs
>after search.
>
>Deeper blue said only 2.1 pawns for white after 73 seconds of search when other
>programs has no problem to see clearly better score for white.
>
>I can explain 1 pawn difference or even 1.5 pawns difference by different
>evaluation but the difference between Crafty's evaluation(4.22) and their
>evaluation(2.1 after 73 seconds) is more than 2 pawns(I mean to the evaluation
>of Rf5+) and it can be explained only by the fact that crafty could see deeper.
>
>Their score at depth 15 is only 1.63 for white so if you compare same depth then
>it is clear that Crafty did better extensions than deeper blue.
>
>If you do not like depth 15 of move 43 because of the bug that cause deeper blue
>to play Rd1 you can take depth 11(6)=17 at move 42 abd you find there a score of
>only 1.36 pawns for white.
>
>I assume that 11(6) means depth 17 with futility pruning and in this case the
>top programs of today clearly do better extensions than deeper blue.
>
>Uri
Did you take into account that pawn=128 or something in deep blue?
Note that if 11(6) is 17 ply they somehow prune 16 ply away.
Deep Blue was said to have next extensions:
- singular extensions with 1 ply extended
- recapture extensions 1 ply extended
- consecutive moves 1/4 ply extended (if same piece moves they extend it)
- 2 moves best (form of threat extension) 1/2 ply extended
So for some reason they do loads of extensions show similar
lines as i do at about the same depth, from tactical reason seen.
Sometimes they need 1 ply less to show it!
It makes no sense forward pruning 6 ply if you have hardware processors
that search 6 ply!
Note that in that case we would see long mainlines which we do not
see. We only see tactical lines extended. Positional lines we can all
explain with the above extensions!
Even with huge pruning it's impossible to search 17 ply.
FHR is a very dubious way of searching. It's very incorrect. I can't
imagine DB ever used it.
FHR basically says next:
IF evaluation + thread >= beta
THEN reduce depth 1 ply;
This can only apply for half of the search depth *at most*.
The only official search depth example i have seen from Hsu was
examining a 'typical' 12 ply depth search!
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