Author: Albert Silver
Date: 07:21:38 04/26/01
Go up one level in this thread
On April 25, 2001 at 19:18:18, Vincent Diepeveen wrote:
>
>it shows regurarly 12(6) which would mean it has finished 18 ply fullwidht
>according to Bob.
>
>That means even with a perfect branching factor
>
>40 (first ply) ==> not taken into account though
>4 (factor 4 for overhead because of using big qsearch)
>let's take an optimal branching factor for deep blue with SE in software
>and also captures added.
>
>optimal branching factor fullwidth 4.5 (it's way more without any extensions
>my b.f. is even bigger fullwidth).
>added to that 0.5 for SE
>added to that 1.0 for capture extensions
>total b.f. = 6.0
>
>6.0 ^ 18 * 4 = 406239826673664 nodes needed.
>
>Ok let's forget even the factor 4 overhead for qsearch
>then it's 101559956668416
>
>Bit big number?
>
>Oh well now let's take the number of nodes explored by deep blue.
>200M nodes a second. Of that 20% was effective according to Hsu (see IEEE99
>publication).
>
>So compared to a single cpu that would be 40M nodes a second.
>Let's even be MILD here for Hsu and ignore the fact and just use 200M
>a second, because Bob is going to complain.
>
>So even when taking the defense of DB into account the
>b.f. was absolutely better as
>
>18th square from 200M x 3 minutes = 18th sq from 36B nodes.
>that's about 3.86
>
>Now that's *impossible* without nullmove everywhere or very dubious
>forward pruning. Note the example of Hsu he takes a 'typical 12 ply search'
>as example.
>
>More likely this 8(6) says nothing and it's simply 8 plies in total from
>which 6 in hardware. To solve many tricks he did the junior/belle trick
>and he just extends in software about every tactical move he sees.
>
>That solves of course testsets bigtime.
>
>Also on the internet Campbell was recently searching during the
>world championship FIDE with deep blue junior (i do not know how
>many processors 30 or so?).
>After many minutes of search he reported his variation was
>a 12 ply search.
I was there, and I happened to record what he said once I was made aware of it.
Following the games with CA6 beta at the time (plug, plug) I was able to include
these comments as a text comment in the notation. I have unfortunately only two
such lines with a text note. Here is what I have with the positions being
commented:
[Event "Brain Games World Championship Match"]
[Site "London, England"]
[Date "2000.10"]
[Round "10"]
[White "Kramnik, Vladimir"]
[Black "Kasparov, Gary"]
[Result ""]
[Eco "E54"]
[Annotator ""]
[Source ""]
1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.e3 O-O 5.Bd3 d5 6.Nf3 c5 7.O-O cxd4
8.exd4 dxc4 9.Bxc4 b6 10.Bg5 Bb7 11.Re1 Nbd7 12.Rc1 Rc8 13.Qb3
Be7 14.Bxf6 Nxf6 ( 14...Bxf6 15.Nb5 Bxf3 16.Qxf3 a6 17.Nd6 Rc7 )
15.Bxe6 fxe6 16.Qxe6+ Kh8 17.Qxe7 Bxf3 18.gxf3 Qxd4 19.Nb5 Qxb2
20.Rxc8 Rxc8 21.Nd6 {rb8 nf7 kg8 nd8 h6 ne6 nh5 qa7, +.83, min depth 11, max
depth 27 (Deep Blue Jr.)
}
Rb8 ( 21...Ra8 22.Nf7+ ( 22.Ne8 Ng8 ) Kg8 23.Nd8 h6 24.Ne6 Nh5
25.Qb7 Re8 26.Qd7 Rb8 ) 22.Nf7+ ( 22.Qxa7 Rf8 23.Qe7 Ra8 24.Nf7+
Kg8 25.Nd8 h6 26.Qf7+ Kh8 27.Ne6 Ng8 28.Re2 Qf6 29.Qb7 $20 )
Kg8 {Nd8 h6 Ne6 Nh5 Qa7 Rc8 Qd7 Qc3 +.87, examining about 35 M pos/sec (DB Jr.)
}
23.Qe6 Rf8 ( 23...h5 24.Ng5+ Kh8 25.Qf5 Rf8 26.Qg6 Qb4 27.Re6
h4 28.Nf7+ Kg8 29.Rxf6 Qe1+ 30.Kg2 h3+ 31.Kxh3 Qf1+ 32.Kh4 $20 )
24.Nd8+ Kh8 25.Qe7
{p-svidler(GM) kibitzes: I've never seen Garry playing so badly. First time in
years he seems to be off-form in an important competition
} *
Here are the two FENS of the positions in question:
[D]2r4k/p3Q1pp/1p1N1n2/8/8/5P2/Pq3P1P/4R1K1 b - -
rb8 nf7 kg8 nd8 h6 ne6 nh5 qa7, +.83, min depth 11, max depth 27 (Deep Blue Jr.)
[D]1r4k1/p3QNpp/1p3n2/8/8/5P2/Pq3P1P/4R1K1 w - -
Nd8 h6 Ne6 Nh5 Qa7 Rc8 Qd7 Qc3 +.87, examining about 35 M pos/sec (DB Jr.)
BTW, considering the irregularity of the notation (lowercase in the first and
capital letters in the second), I think Murray was entering this by hand. Each
comment came with the evaluation, and only after did he had the info on depth
and speed. It wasn't all in a single line as I posted here.
Before you go off on a bend, remember that this was still probably the software
info being displayed on his screen as Bob mentioned, but I'll let you two argue
this. I'm going to go get some more popcorn. :-)
Last thing: he said it was something like 128 processors being used as I recall.
Albert
>
>Now that was like after a lot of time. And with the huge b.f. of
>Deep Blue at those depths (as SE and recapture extensions
>go take their toll on bigger depths in software), it's very likely
>that Deep Blue only searched 1 ply deeper in a bit shorter time!
>
>So there is a source confirming this indirectly!
>
>He told this to channel 211 too, so there are more witnesses if they
>still remember the questions i asked regarding search depth!
>
>Best regards,
>Vincent
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