Author: Amir Ban
Date: 10:05:48 05/09/98
Go up one level in this thread
On May 09, 1998 at 06:35:53, Ingo Althofer wrote:
> PS: As I understand, Amir Ban has "the" DB
>outputs of game 2. Would he be willing to share them with us ?
The printouts themeselves are not in electronic format. I can offer my
report to Kasaparov (given here as an email to Shay), in which I put
what I saw into a readable format. It's included below. Other people
that went over the raw printouts agree with my interpretation.
Christopher Chabris is writing a book on the Deep Blue project and the
match. He asked me for information and I gave him, among else, this
material. There were some fragments published in various places
(including CCC). I see no reason why CCC readers, who will find it more
intersting than anyone else, should not see it.
I think you will find that my tone was careful. I already knew that
Kasparov was suspecting foul-play. I didn't want to make any statement
that would make him jump to conclusions. There are also printouts for
two moves in the opening of game 5. I didn't find anything unusual about
them and did not make a report.
The only addition I would make to this report is a remark on the odd
nature of the PV for Qb6 at ply 10. GM Ronen Har-Zvi pointed out to me
that the move Qa7 in this PV is a simple blunder. How such a move can
appear in a PV is just one more mystery.
Amir
------- Forwarded Message Follows -------
From: "Amir Ban" <amirban@m-sys.com>
To: shayb@spl.co.il
Date: Thu, 15 May 1997 01:49:29 +0000
Subject: IBM printouts
Cc: amirban@m-sys.com
Priority: normal
Shay,
The printouts are not easy to read. It looks like they are a raw log of
whatever went to the operator console, including control characters,
which make them look like a binary dump. There are codes,
abbreviations and numbers whose meaning is not obvious. There are
some things that I don't know the meaning of.
However, overall, I think I understand the chess part of it, and most
of the timing information. I give here a plain-text "translation" for
game 2 only.
In 36. axb5, I can read the printout, but it still doesn't
make perfect sense to me (although I can think of possible
explanations). Maybe I am missing some important
information, or misunderstanding something. I will expand on this
later.
------------------------------------------------------------------------
Game 2
---------
Played 35. Bxd6 with 5 moves and 46:59 min remaining.
Evaluating based on expected reply 35... Bxd6:
Starting at iteration 8 (AB: I guess this means ply 8, not counting
extensions).
Ply 8: 0:01 eval >30 (fail high): Qb6 Qe7 axb5 Rab8 Qxa6 e4 Bxe4
Qe5 g4 Re8 Bg2 Qh2 Kf1 Re3
Qc6 Rxc3
Ply 8: 0:01 eval >61 (fail high): Qb6 Qe7 axb5 Rab8 Qxa6 e4 Bxe4
Qe5 g4 Re8 Bg2 Qh2 Kf1 Re3
Qc6 Rxc3
Ply 8: 0:05 eval 87: Qb6 Qe7 axb5 Rab8 Qxa6 e4 Bxe4 Qe5
g4 Re8 Bg2 Qh2 Kf1 Re3
Ply 9: 0:18 eval 79: Qb6 Qe7 axb5 Rab8 Qxa6 e4 Bxe4 Qe5
g4 Re8 Bg2 Qh2 Kf1 Re3
Ply 10:
35... Bxd6 played by Black (correct guess). Continuing to think on my
clock...
Set planned thinking time to 217 sec. Maximum time ("panic time") to
839 sec.
Ply 10: 1:22 eval 74: Qb6 Qe7 axb5 Rab8 Qxa6 e4 Bxe4 Qe5
Bf3 Rd8 Qa7 Qxc3 Bh5
Ply 11:
For the next 4 minutes, there are no more reports with chess
content. When the planned thinking time arrives, no move is made.
Instead there start appearing messages that look like distress
signals: Messages notifying each 4 seconds passing, and "panic time"
(PT=...) countdown.
Then:
Ply 11: 5:35 eval 48: Qb6 (no principal variation given)
At 6:56 minutes, the "panic time" mechanism is activated, and this
produces:
Ply 11: 6:56 eval 63: axb5 axb5 Qb6 Rxa2 Rxa2 Bc7 Qe6 Kh8
Be4 Rb8 Ra6 Qd8 d6 Bb6
36. axb5 played.
AB:
There are things here that are not easy to understand that are
related to time management. Maybe IBM can clarify this:
A move was not played at the planned thinking time (217 sec). In the
rest of the printouts, a move is always played at this time (with
the message TIMEOUT). In this case not. Maybe some criterion for
playing the move was missing, or maybe Deep-Blue knew at the time
something bad about Qb6, but the printout doesn't show it.
When the score for Qb6 arrived, it wasn't too bad (48), not much
lower than previous iteration (74). Perhaps it was failing low, but
the log doesn't say so.
The "panic time" mechanism, if I understand correctly, was activated
ahead of time. It still had about 7 minutes to go. The mechanism
produced axb5. In normal alpha-beta as I know it, a new principal
variation that was not discovered before cannot be produced just by
stopping the search. Maybe I misunderstand, and first axb5 was found
and this stopped the panic time countdown. If so, why wasn't it
stopped a minute before when Qb6 arrived, and if not, why didn't DB
continue to consider the rest of the valid moves ?
I am merely puzzled. I can't say I see any evidence of wrongdoing here.
Perhaps an operator forced the move here to gain a few minutes. That
wouldn't have affected the game anyway, since DB had plenty of time.
About the variations given:
After Qb6 DB expects Black to give up 3 pawns for an attack on the
white king, and considers it almost equal compensation. I don't know
how many other programs would evaluate it this way. This says
something about DB's evaluation much more than its search depth. Some
of the PV moves are weird, possibly completely wrong, but that often
happens at great depths. For all I know, DB's judgement may have been
excellent here.
------------------------------------------------------------------------
Played 36. axb5 with 4 moves and 40:28 minutes remaining.
Evaluating based on expected reply 36... axb5
Starting at iteration 8.
Ply 8: 0:01 eval >30 (fail high): Qb6 Rxa2 Rxa2 Bc7 Qe6 Kh8
Be4 Rb8 Ra6 Qd8 d6 Bb6
Ply 8: 0:04 eval 53: Qb6 Rxa2 Rxa2 Bc7 Qe6 Kh8
Be4 Rb8 Ra6 Qd8 d6 Bb6
Ply 9: 0:09 eval 53: Qb6 Rxa2 Rxa2 Bc7 Qe6 Kh8
Be4 Ra8 Kh2 Rb8 g3 Qf8
Ply 10: 0:33 eval 55: Qb6 Rxa2 Rxa2 Bc7 Qe6 Kh8
Be4 Qf8 Kh1 Bd6 Ra6 Rd8 Ra7
Ply 11:
36... axb5 played by Black (correct guess). Continuing to think on my
clock...
Set planned thinking time to 199 sec. Maximum time ("panic time") to
709 sec.
Ply 11: 1:24 eval 32: Qb6 (no principal variation given)
Ply 11: 3:02 eval 37: Be4 Rcb8 g3 Qd8 Ra6 Rxa6 Rxa6 Bc7 Rxf6
(AB: This PV is ridiculous. I don't know what it means).
Ply 12:
Timeout occured after 199 sec.
Ply 12: 3:19 eval 37: Be4 Rcb8 g3 Qd8 Kg2 Rxa2 Rxa2 Bc7
Qa7 Bb6 Qa6 Qd7
(AB: Since the search was timed out, I don't know where this new PV
comes from. The eval did not change).
37. Be4 played.
AB:
Timing here is normal. Some variations here are weird.
There is no information given why Qb6 failed low at ply 11.
The final move Be4 was accepted with a PV ending with a ridiculous
Rxf6. Perhaps IBM know what this means.
The move Be4 appears in many variations of the 36th and 37th moves.
Looks like the evaluation function likes this square for the bishop,
and it was played on general principles.
-----------------------------------------------------------------------------
Amir
----------------------------------------
Amir Ban e-mail: amirban@m-sys.com
M-Systems Ltd. Tel.: +972 3 647 7776
Fax : +972 3 647 6668
-----------------------------------------
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