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Subject: Re: Bug in CHEST - bugfix available

Author: Ernst Walet

Date: 07:04:30 05/08/02

Go up one level in this thread


On May 08, 2002 at 02:26:52, Dann Corbit wrote:

>On May 08, 2002 at 02:18:23, Dann Corbit wrote:
>
>>On May 08, 2002 at 01:31:36, Dann Corbit wrote:
>>
>>>On May 07, 2002 at 15:09:57, Ernst Walet wrote:
>>>
>>>>On May 07, 2002 at 14:18:50, Dann Corbit wrote:
>>>>
>>>>>On May 05, 2002 at 13:55:00, Heiner Marxen wrote:
>>>>>
>>>>>>On April 28, 2002 at 22:00:22, Heiner Marxen wrote:
>>>>>>
>>>>>>>On April 28, 2002 at 18:18:38, Heiner Marxen wrote:
>>>>>>>
>>>>>>>>On April 28, 2002 at 08:00:15, Vincent Vega wrote:
>>>>>>>>
>>>>>>>>>Simplified position to show the bug:
>>>>>>>>>[D]8/8/8/8/8/8/4KP2/R1Qn3k w - - 0 1
>>>>>>>>>
>>>>>>>>>This is a mate in 2 (1. Qxd1+).
>>>>>>>>>
>>>>>>>>>But CHEST says:
>>>>>>>>>
>>>>>>>>>CHEST version 3.19, 18-Dec-1999
>>>>>>>>>Input file: 'xx'
>>>>>>>>>Reading job:
>>>>>>>>>#	xx
>>>>>>>>>W:  Ke2 Qc1 Ra1 Pf2 (4)
>>>>>>>>>B:  Kh1 Nd1 (2)
>>>>>>>>>FEN: 8/8/8/8/8/8/4KP2/R1Qn3k w - -
>>>>>>>>>analysing (mate in 2 moves):
>>>>>>>>>No solution in 2 moves.
>>>>>>>>>refu  1: Qxd1+   --      [  1-]   M2: move
>>>>>>>>>refu  2: Qc6+    --      [  1-]   M2: move
>>>>>>>>>refu  3: Qh6+    Kg1     [  1-]
>>>>>>>>>refu  4: f3      --      [  1-]   M2: move
>>>>>>>>>refu  5: f4      --      [  1-]   M2: move
>>>>>>>>>refu  6: Rb1     --      [  1-]   M2: move
>>>>>>>>>refu  7: Ra2     --      [  1-]   M2: move
>>>>>>>>>refu  8: Ra3     --      [  1-]   M2: move
>>>>>>>>>refu  9: Ra4     --      [  1-]   M2: move
>>>>>>>>>refu 10: Ra5     --      [  1-]   M2: move
>>>>>>>>>refu 11: Ra6     --      [  1-]   M2: move
>>>>>>>>>refu 12: Ra7     --      [  1-]   M2: move
>>>>>>>>>refu 13: Ra8     --      [  1-]   M2: move
>>>>>>>>>refu 14: Qb1     --      [  1-]   M2: move
>>>>>>>>>refu 15: Qc2     --      [  1-]   M2: move
>>>>>>>>>refu 16: Qc3     --      [  1-]   M2: move
>>>>>>>>>refu 17: Qc4     --      [  1-]   M2: move
>>>>>>>>>refu 18: Qc5     --      [  1-]   M2: move
>>>>>>>>>refu 19: Qc7     Kg1     [  1-]
>>>>>>>>>refu 20: Qc8     --      [  1-]   M2: move
>>>>>>>>>refu 21: Qd2     --      [  1-]   M2: move
>>>>>>>>>refu 22: Qe3     --      [  1-]   M2: move
>>>>>>>>>refu 23: Qf4     Kg1     [  1-]
>>>>>>>>>refu 24: Qg5     --      [  1-]   M2: move
>>>>>>>>>refu 25: Qb2     --      [  1-]   M2: move
>>>>>>>>>refu 26: Qa3     --      [  1-]   M2: move
>>>>>>>>>refu 27: Kd2     --      [  1-]   M2: move
>>>>>>>>>refu 28: Ke1     --      [  1-]   M2: move
>>>>>>>>>refu 29: Kf3     --      [  1-]   M2: move
>>>>>>>>>refu 30: Kxd1    --      [  1-]   M2: move
>>>>>>>>>refu 31: Kf1     Ne3+    [  1-]
>>>>>>>>>refu 32: Kd3     --      [  1-]   M2: move
>>>>>>>>>Time (virt) = 0.000 sec
>>>>>>>>
>>>>>>>>Sadly, I have to confirm this fact: this is a bug in Chest.
>>>>>>>>If I specify option "-2" to suppress the "2-mate-heuristic", it finds the
>>>>>>>>mate in 2:
>>>>>>>>
>>>>>>>> Qxd1+  Kh2    Qh1#
>>>>>>>>        Kg2    Qh1#
>>>>>>>>
>>>>>>>>Hence, the bug is in the "mate2" module.  Since that one is a really complex
>>>>>>>>one, it will take some time to track it down.
>>>>>>>>When I have found it, I will report under what circumstances it does appear.
>>>>>>>
>>>>>>>Fortunately, I could track down this bug.
>>>>>>
>>>>>>[snip]
>>>>>>>It is quite easy to correct this bug, and within the next week I will
>>>>>>>provide a corrected source module.
>>>>>>>It will be announced here, and be available through my web page.
>>>>>>
>>>>>>   http://www.drb.insel.de/~heiner/Chess/chest.html
>>>>>>
>>>>>>contains a reference to the corrected source code "mate2.c":
>>>>>>
>>>>>>   http://www.drb.insel.de/~heiner/Chess/mate2.c
>>>>>>
>>>>>>>Hopefully Dann will then provide a corrected win32 executable.
>>>>>>>Since the circumstances for the bug to occur are not really very rare,
>>>>>>>I'd recommend upgrading to the new version when available.
>>>>>>
>>>>>>I can't speak for Dann, but it would be very nice of him to offer
>>>>>>an updated source package, and more importantly, a corrected binary.
>>>>>>(I myself cannot compile for windows).
>>>>>
>>>>>Everything:
>>>>>ftp://cap.connx.com/pub/chess-solvers/chest/
>>>>>
>>>>>The package in a zip:
>>>>>ftp://cap.connx.com/pub/chess-solvers/chest/CHEST319.ZIP
>>>>>
>>>>>The binary only:
>>>>>ftp://cap.connx.com/pub/chess-solvers/chest/chest319.exe
>>>>
>>>>
>>>>Dan, when accessing the first link, I immediately get attacked by a trojan
>>>>horse.  This is the message drom my fire wall:
>>>>
>>>>Soket de Trois v1. Trojan horse at cap.connx.com (209.20.248.158)
>>>>
>>>>Maybe you should check your server?
>>>
>>>I shut down my ftp site, and I am running the virus scanner over all drives.
>>>Pretty strange that it did not get diagnosed.
>>>I have McAfee Virus Scan 4.5.1, and it gets updated over the net every night.
>>
>>I searched my registry for mschv32.* and did not find anything.
>>I searched all hard drives my system has access to for mschv32.* and it is not
>>found anywhere.
>>
>>I have several million files on my total available disk storage, so the virus
>>scan will run for 15 hours or so.
>
>None of the following are located anywhere on my system:
>
>rsrcload.exe
>mgadeskdll.exe
>csmctrl32.exe
>
>So it would appear that I do not have any of the variants.
>Still running the virus scanner (which won't complete until tomorrow)

OK, no harm done as my fire wall blocked it.  I have tried it a second time
yesterday to be sure, and the warning came up again.  I will try again later
this day and report to you.

Good luck,
Ernst.



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