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Subject: Re: EGTB question

Author: Eugene Nalimov

Date: 11:17:32 10/01/01

Go up one level in this thread


On October 01, 2001 at 12:04:51, Robert Hyatt wrote:

>On October 01, 2001 at 09:56:06, Mike Hood wrote:
>
>>Eugene, I think I understand your answer in part, but please help me further.
>>I've quoted the whole file kbpk.tbs below, and I have three questions:
>>
>>1) There is a Mate in 31 listed, but no Mate in 30 or Mate in 29. Is this
>>because the Mate in 31 involves an immediate transition into another tablebase,
>>such as kpk.tbs? Maybe if you could tell me the exact position of this Mate in
>>31 it would be obvious to me.
>
>Most likely it is a transposition into a KBN vs K endings.  In a position
>where promoting to a queen would be a stalemate.

[D]/3P/KBk////// w

>>
>>2) Why are no broken positions listed for btm? I presume that "wka1 wba6 wpa7
>>bkb1" is at least one broken position for btm.
>>
>>3) All the numbers ought to be even, because every position containing one pawn
>>can be mirrored left-right. Is the presence of odd numbers because your
>>statistics are the number of positions in your already simplified/compressed
>>chess board?

Reported numbers are number of positions in file, i.e. after indexing removed
loat of duplicate and illegal positions. Including illegal position you
reported.

Eugene

>>Thanks,
>>
>>Mike
>>
>>kbpk.tbs
>>========
>>wtm: Draws:              174804
>>wtm: Mate in  31:             1
>>wtm: Mate in  28:             1
>>wtm: Mate in  26:            11
>>wtm: Mate in  25:             4
>>wtm: Mate in  24:            25
>>wtm: Mate in  23:           167
>>wtm: Mate in  22:           476
>>wtm: Mate in  21:          1917
>>wtm: Mate in  20:          6110
>>wtm: Mate in  19:         17489
>>wtm: Mate in  18:         36103
>>wtm: Mate in  17:         85135
>>wtm: Mate in  16:        150419
>>wtm: Mate in  15:        186502
>>wtm: Mate in  14:        209994
>>wtm: Mate in  13:        283840
>>wtm: Mate in  12:        406655
>>wtm: Mate in  11:        460888
>>wtm: Mate in  10:        442601
>>wtm: Mate in   9:        440135
>>wtm: Mate in   8:        436186
>>wtm: Mate in   7:        406369
>>wtm: Mate in   6:        303115
>>wtm: Mate in   5:        157067
>>wtm: Mate in   4:         68023
>>wtm: Mate in   3:         29622
>>wtm: Mate in   2:          9838
>>wtm: Mate in   1:          3118
>>wtm: Broken positions:   500513
>>btm: Lost in   0:           117
>>btm: Lost in   1:           873
>>btm: Lost in   2:          2793
>>btm: Lost in   3:          8892
>>btm: Lost in   4:         29591
>>btm: Lost in   5:         84157
>>btm: Lost in   6:        226693
>>btm: Lost in   7:        415728
>>btm: Lost in   8:        455096
>>btm: Lost in   9:        447616
>>btm: Lost in  10:        430805
>>btm: Lost in  11:        422716
>>btm: Lost in  12:        394004
>>btm: Lost in  13:        338834
>>btm: Lost in  14:        282260
>>btm: Lost in  15:        243794
>>btm: Lost in  16:        209974
>>btm: Lost in  17:        137192
>>btm: Lost in  18:         70856
>>btm: Lost in  19:         33990
>>btm: Lost in  20:         13627
>>btm: Lost in  21:          7010
>>btm: Lost in  22:          4168
>>btm: Lost in  23:          2492
>>btm: Lost in  24:           944
>>btm: Lost in  25:           384
>>btm: Lost in  26:           129
>>btm: Lost in  27:            48
>>btm: Lost in  28:            24
>>btm: Lost in  31:             2
>>btm: Draws:              859923
>>
>>
>>
>>On September 28, 2001 at 13:37:24, Eugene Nalimov wrote:
>>
>>>DTM, not DTC. After capture or promotion resulting position is stored in the
>>>other TB, not in the current one.
>>>
>>>Eugene
>>>
>>>On September 28, 2001 at 12:38:55, Mike Hood wrote:
>>>
>>>>Thanks for the reply, Eugene. I'm willing to accept I may be wrong, but how do
>>>>you explain the discrepancies I named?
>>>>
>>>>Mike
>>>>
>>>>On September 28, 2001 at 11:11:33, Eugene Nalimov wrote:
>>>>
>>>>>There is no bug in TBSTAT, and statistics is correct.
>>>>>
>>>>>Eugene
>>>>>
>>>>>On September 28, 2001 at 08:27:37, Mike Hood wrote:
>>>>>
>>>>>>On September 19, 2001 at 04:23:39, Les Fernandez wrote:
>>>>>>
>>>>>>>Has anyone tabulated the total win-lose-draw-broken positions for first the 3
>>>>>>>then 4 and then the 5 piece sets?  I know that the information is available on
>>>>>>>Bobs ftp site but hoping that someone has already done it for both WTM and BTM
>>>>>>>so I dont have to do them one by one.
>>>>>>>
>>>>>>>ie:
>>>>>>>
>>>>>>>EGTB     WINS     LOSE     DRAW     BROKEN
>>>>>>>
>>>>>>> 3
>>>>>>> 4
>>>>>>> 5
>>>>>>
>>>>>>This is theoretically possible, but not very sensible at the moment. Most of the
>>>>>>TBS files on Robert Hyatt's ftp server are defective, probably due to a bug in
>>>>>>TBSTAT.
>>>>>>
>>>>>>For instance:
>>>>>>
>>>>>>krrk.tbs -- On black's move there are 1032 positions that lose in 16, but on
>>>>>>white's move the longest mate is Mate in 7.
>>>>>>
>>>>>>kqrkr.tbs -- On black's move there are 60 moves that are Mate in 5, but there
>>>>>>are ZERO moves that are Mate in 4.
>>>>>>
>>>>>>kbpk.tbs -- On white's move there is 1 position that is Mate in 31, but there
>>>>>>are ZERO moves that are Mate in 30.
>>>>>>
>>>>>>In most of the TBS files the number of broken positions is not listed.
>>>>>>
>>>>>>Over 50% of the TBS files are obviously defective, and I can't vouch for the
>>>>>>validity of the others. And, to ask a naive question, shouldn't the number of
>>>>>>Mates/Losses/Draws in a pawnless tablebase always be divisible by 4?
>>>>>>
>>>>>>I've reported the bug to Eugene by email a few weeks ago, but it hasn't been
>>>>>>fixed yet.
>>>>>>
>>>>>>Mike



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