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Subject: Another useless position

Author: Vincent Diepeveen

Date: 14:26:23 04/28/04

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On April 28, 2004 at 15:03:41, Gerd Isenberg wrote:

>On April 28, 2004 at 12:12:17, Vincent Diepeveen wrote:
>
>>On April 28, 2004 at 11:32:00, Gerd Isenberg wrote:
>>
>>>On April 28, 2004 at 09:44:01, Vincent Diepeveen wrote:
>>>
>>>>>I tried double nullmove suggested by Vincent too, without any precondition like
>>>>>eval - margin >= beta. Vincent is probably right - it seems to work great, and
>>>>>solves a lot of test positions a few percent faster. But with some positions,
>>>>
>>>>And how many plies does double nullmove on average search deeper in a normal
>>>>chess position?
>>>
>>>It looks like iterations terminate about 5-10% earlier on average.
>>>I fear my BF isn't that good to earn an additional ply in standard matches.
>>>
>>>My impression with your really great double nullmove idea is
>>>that it doesn't work so good in critical and probably game decisive positions,
>>>even in early middlegame root positions. But of course that may be due to my
>>>implemetation and sideeffects with other things in my search.
>>
>>this is a big nonsense and you know it.
>
>Sorry Vincent, no - simply my vague impression.
>Similar to some more additional knowledge, which slows you down a bit, but helps
>to find some moves one ply or even more plies earlier.
>
>Of course i have to investigate it a bit more and play some matches.
>
>>
>>theoretical chess studies which never come onto the board you cannot call
>>'critical game deciding positions'.
>>
>>You show up with some insane positions where uncommon passer knowledge, checks
>>or pawn evaluation are decisive in terms of whether you find a winning move or
>>not and you use that to test 'zugzwang'.
>
>I thought BT-test positions are from some gm matches?
>Anyway, there are some other positions i tried so far from my favourite testset,
>even positions from games IsiChess played, like this am position.
>
>6k1/4bppp/2p3n1/5Q2/1qPB4/1P1R1BP1/r6P/7K w - - am Qc8

Another useless position.

nullmove has nothing to do with it.

Basically you want to avoid a draw score (in fact it's losing) for the line
shown by diep at 12 ply:

00:03 196987 701276 0 (2) 8 (18,149) 0.157 Bd4-g1 Ra2-a1 Qf5-e4 Qb4-a5 Rd3-d1 Ra
1xd1 Bf3xd1 Ng6-e5
00:07 207529 1510818 0 (2) 9 (47,269) 0.596 Bd4-g1 Ra2-a1 Rd3-d1 Ra1xd1 Bf3xd1 N
g6-f8 Qf5-e4 Be7-c5 Bd1-c2 Bc5xg1 Kh1xg1
++ f5-c8 procnr=1 terug=597 org=[596;597] newwindow=[596;520000]
00:08 208348 1848052 0 (2) 9 (63,315) 0.831 Qf5-c8 Ng6-f8 Qc8xc6 Qb4-e1 Bd4-g1 R
a2-a1 Qc6-b6 Qe1-f1 Bf3-e4 f7-f5 Be4-d5 Kg8-h8
00:11 207726 2428323 0 (2) 10 (96,514) 0.831 Qf5-c8 Ng6-f8 Qc8xc6 Qb4-e1 Bd4-g1
Ra2-a1 Qc6-b6 Qe1-f1 Bf3-e4 f7-f5 Be4-d5 Kg8-h8
00:24 210851 5123688 0 (2) 11 (147,812) 0.617 Qf5-c8 Be7-f8 Qc8-e8 Qb4-a3 Qe8xc6
 Qa3-c1 Bf3-d1 Qc1-b1 Qc6-f3 Bf8-b4 Qf3-f1 f7-f6
01:21 210359 17064390 0 (2) 12 (359,1731) 0.000 Qf5-c8 Ng6-f8 Qc8xc6 Qb4-e1 Bd4-
g1 Ra2-a1 Qc6-b6 Qe1-f1 Bf3-e4 Qf1-e2 Be4-f5 Qe2-f1 Bf5-e4
++ d4-g1 procnr=1 terug=1 org=[0;1] newwindow=[0;520000]
02:59 212145 38090694 0 (2) 12 (384,1821) 0.427 Bd4-g1 Ra2-a1 Rd3-d1 Ra1xd1 Bf3x
d1 Ng6-f8 Bd1-c2 g7-g6 Qf5-f3 Be7-c5 Bg1xc5 Qb4xc5 Bc2-e4 f7-f5

All you need is a mate in 1 extension to solve this position quicker. Diep does
not have it, so it needs a stupid 12 ply to find it.

Let me put diep to Adaptive nullmove R=3,R=2 (if depthleft <= 4 ply left i use
R=2) to proof my point:

00:13  88936 1188185 0 (2) 8 (21,152) 0.157 Bd4-g1 Ra2-a1 Qf5-e4 Qb4-a5 Rd3-d1 R
a1xd1 Bf3xd1 Ng6-e5
00:23  85233 1961218 0 (2) 9 (55,268) 0.596 Bd4-g1 Ra2-a1 Rd3-d1 Ra1xd1 Bf3xd1 N
g6-f8 Qf5-e4 Be7-c5 Bd1-c2 Bc5xg1 Kh1xg1
++ f5-c8 procnr=1 terug=597 org=[596;597] newwindow=[596;520000]
00:26  89766 2389595 0 (2) 9 (64,299) 0.831 Qf5-c8 Ng6-f8 Qc8xc6 Qb4-e1 Bd4-g1 R
a2-a1 Qc6-b6 Qe1-f1 Bf3-e4 f7-f5 Be4-d5 Kg8-h8
00:42  81927 3454893 0 (2) 10 (92,503) 0.831 Qf5-c8 Ng6-f8 Qc8xc6 Qb4-e1 Bd4-g1
Ra2-a1 Qc6-b6 Qe1-f1 Bf3-e4 f7-f5 Be4-d5 Kg8-h8
01:07  83603 5615629 0 (2) 11 (150,798) 0.625 Qf5-c8 Ng6-f8 Qc8xc6 Qb4-e1 Bd4-g1
 Qe1-b1 Qc6-e4 Be7-b4 Rd3-e3 Qb1-c1 Bf3-e2 Bb4-c5
02:51 135608 23258259 0 (2) 12 (227,1245) 0.001 Qf5-c8 Ng6-f8 Qc8xc6 Qb4-e1 Bd4-
g1 Ra2-a1 Qc6-b6 Nf8-e6 Rd3-d7 Be7-f8 Bf3-d5 Ne6-c5 Bd5xf7 Kg8-h8
++ d4-g1 procnr=0 terug=2 org=[1;2] newwindow=[1;520000]
05:27 169710 55529294 0 (2) 12 (246,1343) 0.449 Bd4-g1 Qb4-b8 Rd3-d7 Ra2-a1 Rd7-
d1 Ra1-a3 Bf3xc6 Ng6-e5 Bc6-a4 Qb8-b7 Rd1-d5 Ne5xc4

It finds of course this tactical trick at the same depth with more nodes. don't
watch the search times. shared memory f'ed up a bit again despite that i
virtuallock() it. Windows XP is one big unsecure bug.

I bet forward pruning works like the sun in this position. You just want to hunt
a few attacked pieces here.

>>
>>Both your positions have nothing to do with zugzwang in absolute respect. Just
>>get a fullwidth search with singular extensions and in your testset positions it
>>will outgun anything you do with nullmove, i'm sure of it.
>
>Ok, i will try and see.
>
>>
>>As long as we are not speaking at the same level with each other, i can't help
>>it that fullwidth+singular extensions solve anything you show up with sooner.
>>
>
>I fear with search topics and parallel search i'll never reach your level and
>brilliancy ;-)
>
>Cheers,
>Gerd



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