Author: William Penn
Date: 21:29:49 11/24/03
Go up one level in this thread
On November 24, 2003 at 12:16:50, Uri Blass wrote:
>On November 24, 2003 at 11:51:45, William Penn wrote:
>
>>On November 24, 2003 at 05:24:17, Brian Katz wrote:
>>
>>>It appears that the latest Fritz 8 upgrade from the Playchess server has
>>>corrected version 8.0.0.23 in that the "NOT" capturing on e4 problem seems to
>>>have been corrected. In help menu>About Fritz the date will change to(Nov 13
>>>2003). Just the other day in the following diagram before the recent upgrade,
>>>version 8.0.0.23 would not capture on e4, which is clearly the best move. Now
>>>after the recent upgrade fritz 8.0.0.23 takes on e4 immediately.
>>>[D]rnbqkb1r/pp1ppppp/2p2n2/8/2B1P3/P4N2/1PPP1PPP/RNBQK2R b
>>>Has anyone else found this to be true as well?
>>>Brian Katz
>>
>>I don't know if this is relevant to your discussion of the e4 capture bug in
>>Fritz 8.0.0.23, but I notice that this is not a possible situation in a real
>>chess game. The position can be achieved via the following sequence of moves,
>>but then it's White's turn to move (not Black's): 1.e4 c6 2.Nf3 Nf6 3.Bc4 Ng8
>>4.a3 Nf6. To create the situation which you pose with black to move, White would
>>somehow have to lose a tempo, but I believe that's impossible (unless I'm
>>overlooking something obvious).
>>WP
>
>It is very simple for white to lose a tempo
>
>[Event "Edited game"]
>[Site "URI-PC"]
>[Date "2003.11.24"]
>[Round "-"]
>[White "-"]
>[Black "-"]
>[Result "*"]
>
>1. e3 c6 2. Nf3 Nf6 3. Bc4 Ng8 4. e4 Nf6 5. a3
>*
>
>
>Uri
I was blind. Yes, of course! :o)
~~~~~~~~~~~~
Using Michael Drexel's test position (see four tests below) and my Shredder 7
GUI (after Nov2003 update) in infinite analysis mode shows that the Fritz
8.0.0.23 engine has the e4-capture bug. Other engines tested do not have it. So
it is not caused by the updated Nov2003 Shredder 7 GUI, which is presumably the
same as the updated Nov2003 Fritz 8 GUI. My Fritz 8.0.0.23 engine was not
modified by the Nov2003 update as indicated by its properties; nevertheless I
tried both the pre-Nov2003 and post-Nov2003 instances and they give essentially
identical results.
[D] 3qkb1r/2pppppp/1p3n2/8/4P3/1B6/1PPR1KPP/3Q3R b - - 0 1
------------------------------------------------------------------------------
Fritz 8.0.0.23 (after Nov2003 update) 15/15, 899kN/s, about 10 minutes
1. = (-0.22): 1...Qa8 2.Rf1 Nxe4+ 3.Kg1 Nxd2 4.Bxf7+ Kd8 5.Qxd2 Kc8 6.Bd5 Qa4
2. = (0.00): 1...e6 2.Qf3 Bc5+ 3.Ke2 Qa8 4.e5 Qe4+ 5.Kd1 Qxe5 6.Qa8+ Ke7
3. = (0.06): 1...h5 2.Qf3 Ng4+ 3.Ke2 e6 4.Rf1 Ne5 5.Qg3 f6 6.Bxe6 h4 7.Qc3
4. = (0.25): 1...Nxe4+ 2.Ke2 Nxd2 3.Qxd2 e6 4.Ra1 Bd6 5.Qd4 Kf8 6.Kf3 Bc5
5. ² (0.37): 1...e5 2.Re1 Bc5+ 3.Kf1 h5 4.Qf3 h4 5.Red1 d6 6.Ra1 Kf8 7.Bd5
------------------------------------------------------------------------------
Fritz 8.0.0.23 (before Nov2003 update) 15/15, 904kN/s, about 9 minutes
1. = (-0.22): 1...Qa8 2.Rf1 Nxe4+ 3.Kg1 Nxd2 4.Bxf7+ Kd8 5.Qxd2 Kc8 6.Bd5 Qa4
2. = (0.00): 1...e6 2.Qf3 Bc5+ 3.Ke2 Qa8 4.e5 Qe4+ 5.Kd1 Qxe5 6.Qa8+ Ke7
3. = (0.06): 1...h5 2.Qf3 Ng4+ 3.Ke2 e6 4.Rf1 Ne5 5.Qg3 f6 6.Bxe6 h4 7.Qc3
4. = (0.25): 1...Nxe4+ 2.Ke2 Nxd2 3.Qxd2 e6 4.Ra1 Bd6 5.Qd4 Kf8 6.Kf3 Bc5
5. ² (0.37): 1...e5 2.Re1 Bc5+ 3.Kf1 h5 4.Qf3 h4 5.Red1 d6 6.Ra1 Kf8 7.Bd5
------------------------------------------------------------------------------
Fritz 8.0.0.5 (original) 15/15, 886kN/s, about 10 minutes
1. -+ (-2.03): 1...Nxe4+ 2.Ke2 Nxd2 3.Qxd2 e6 4.Ra1 Bd6 5.Qd3 Kf8 6.Qf3 c6
2. = (-0.16): 1...Qa8 2.Rf1 Nxe4+ 3.Kg1 Nxd2 4.Bxf7+ Kd8 5.Qxd2 Kc8 6.Bd5 Qa4
3. = (0.00): 1...e6 2.Qf3 Bc5+ 3.Ke2 Qa8 4.e5 Qe4+ 5.Kd1 Qxe5 6.Qa8+ Ke7
4. = (0.06): 1...h5 2.Qf3 Ng4+ 3.Ke2 e6 4.Rf1 Ne5 5.Qg3 f6 6.Bxe6 h4 7.Qc3
5. ² (0.37): 1...e5 2.Re1 Bc5+ 3.Kf1 h5 4.Qf3 h4 5.Bd5 h3 6.g3 Kf8 7.Ra1 Nxd5
------------------------------------------------------------------------------
Shredder704.eng (from Mar2003 update) 15/15, 344kN/s, about 11 minutes
1. -+ (-3.40): 1...Nxe4+ 2.Ke2 Nxd2 3.Qxd2 Qa8 4.Kf2 e6 5.Rd1 Bc5+ 6.Kf1 Qd8
2. ³ (-0.51): 1...Qa8 2.Qa1 Qb7 3.Ke1 e6 4.e5 Ng4 5.Qa4 Nxe5 6.Re2 b5 7.Qd4
3. = (-0.17): 1...e6 2.Re1 Qa8 3.Qe2 Qa5 4.Rdd1 Qe5 5.g3 h5 6.Kg2 h4
4. = (-0.12): 1...h5 2.Qf3 e6 3.h3 Bb4 4.c3 Bc5+ 5.Ke2 Qa8 6.Rhd1 d6 7.Bc2 Qa2
5. = (0.05): 1...e5 2.Re1 Bc5+ 3.Kf1 d6 4.Qe2 Kf8 5.Qf3 Qc8 6.Ra1 b5 7.Ba4
------------------------------------------------------------------------------
Brian Katz's test position does not demonstrate the e4 capture bug with Fritz
8.0.0.23 (see two tests below), nor did several other test positions which I set
up at random where clearly a black knight should capture a white pawn on the e4
square. So this bug only happens with certain positions, but I do not know what
special criteria are required.
[D] rnbqkb1r/pp1ppppp/2p2n2/8/2B1P3/P4N2/1PPP1PPP/RNBQK2R b KQkq - 0 1
------------------------------------------------------------------------------
Fritz 8.0.0.23 (after Nov2003 update) 16/16, 814kN/s, 7 minutes
1. ³ (-0.47): 5...Nxe4 6.0-0 d5 7.Be2 e6 8.d3 Nf6 9.Bg5 Bd6 10.Nbd2 0-0 11.Re1
2. = (-0.03): 5...d5 6.exd5 cxd5 7.Be2 d4 8.Bc4 Nc6 9.d3 Nd7 10.0-0 Nde5
3. = (0.25): 5...b5 6.Bd3 d6 7.Nc3 Qa5 8.0-0 b4 9.Na2 bxa3 10.Nc3 Qh5 11.Rxa3
4. ² (0.28): 5...d6 6.e5 dxe5 7.Nxe5 e6 8.d4 Bd6 9.0-0 0-0 10.Nc3 Nbd7 11.Re1
5. ² (0.41): 5...e6 6.e5 d5 7.Be2 Nfd7 8.d4 c5 9.c3 Be7 10.0-0 0-0 11.Nbd2
------------------------------------------------------------------------------
Fritz 8.0.0.23 (before Nov2003 update) 16/43, 825kN/s, 8 minutes
1. ³ (-0.41): 5...Nxe4 6.0-0 d5 7.Be2 Nd7 8.d3 Nd6 9.d4 Nf6 10.Ne5 Bf5 11.Nd2
2. = (-0.03): 5...d5 6.exd5 cxd5 7.Be2 d4 8.Bc4 Nc6 9.d3 Bg4 10.Nbd2 e6 11.h3
3. = (0.22): 5...b5 6.Bd3 d6 7.Nc3 a5 8.Be2 Bb7 9.d3 Nbd7 10.0-0 b4 11.axb4
4. ² (0.31): 5...d6 6.e5 dxe5 7.Nxe5 e6 8.d4 Bd6 9.0-0 0-0 10.f4 Nbd7 11.Nd2
5. ² (0.41): 5...e6 6.e5 d5 7.Be2 Nfd7 8.d4 c5 9.c3 Be7 10.0-0 0-0 11.Nbd2
------------------------------------------------------------------------------
This is the first time I have run any tests relating to the Fritz 8.0.0.23
e4-capture bug, and I am not an expert in this area.
WP
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