Author: José Carlos
Date: 12:37:09 10/28/01
Go up one level in this thread
On October 28, 2001 at 14:04:54, Heiner Marxen wrote:
>On October 28, 2001 at 13:33:17, Robin Smith wrote:
>
>>On October 28, 2001 at 10:55:27, José Carlos wrote:
>>
>>>On October 28, 2001 at 06:53:06, José Carlos wrote:
>>>
>>>> I managed to make EGTB's work properly except in positions with pawn/s. I
>>>>checked the tablebases by making crafty think in some positions; it worked
>>>>perfectly. For example, in the following position it returns draw:
>>>>
>>>>[D]8/7k/5K2/8/2B5/8/7P/8 b - - 0 31
>>>>
>>>> Now, my program says black is checkmated!
>>>> I tested lots of positions without pawns, and worked fine, so I guess I have a
>>>>bug somewhere related to pawns, but tracing the program I can't see anything
>>>>strange.
>>>> Can anyone please try this position and trace it?
>>>> My numbers:
>>>> IDescFindFromCounters (rgiCounters) returns 24
>>>> PfnIndCalc(iTb,side) (psqW,psqB,sqEnP,fInvert) returns 1557728
>>>> L_TbtProbeTable (iTb,side,ind) returns 32766 (the checkmate!!)
>>>>
>>>> Do you guys get the same numbers? Anyone got a clue what I'm doing wrong?
>>>>Should I post some code so you can check?
>>>>
>>>> Thanks in advance,
>>>>
>>>> José C.
>>>
>>> As I started the amalisys, the given data is for the position after ...Kh6
>>>
>>> José C.
>>
>>Hi Jose,
>>
>>The position before Kh6 is drawn. The position after Kh6 white wins.
>>
>>For example:
>>
>>1... Kh6?? 2. Bd3 Kh5 3. h3 Kh4 4. Bf5 Kh5 5. Kg7 Kg5 6. Bg4 Kh4 7. Kh6 Kg3 8.
>>Kg5
>>
>>Analyzed without TB's, so there may be a faster win, but you get the idea.
>>
>>Robin
>
>For the position after Kh6:
>[D]8/8/5K1k/8/2B5/8/7P/8 w - -
>Crafty (18.10) with 4-piece EGTBs gives (immediately):
>Black(2): setboard 8/8/5K1k/8/2B5/8/7P/8 w - -
>1. Bd3 Kh5 2. Bf5 Kh4 3. h3 Kh5 4. Kg7 Kg5 5. Bg4 Kf4 6. Kg6 Kg3
>7. Kg5 Kf2 8. Kf4 Ke1 9. Ke3 Kf1 10. Bf3 Ke1 11. h4 Kf1 12. h5 Kg1
>13. Kf4 Kf1 14. h6 Ke1 15. Ke3 Kf1 16. h7 Ke1 17. h8=Q Kf1 18. Qh1#
>
>i.e. Crafty thinks it is a mate in 18. Chest confirms. With debug mode
>enabled it tells some details:
>
>% EGTB found tables for max 4 pieces
>% EGTB uses 1542.1K memory internally
>> eg_probe FEN: 8/8/5K1k/8/2B5/8/7P/8 w - -
>= eg_probe cntarr=1,0,1,0,0,0,0,0,0,0,
>= eg_probe iTb=24
>= eg_probe fInvert=0
>= eg_probe sqarr:
> [0][1] = 17 = 17
> [0][2] = 200
> [0][3] = 164535332 = 32
> [0][4] = 20000000
> [0][5] = 0
> [0][6] = 55 = 55
> [1][1] = 0
> [1][2] = 27777706674
> [1][3] = 1001657427
> [1][4] = 20000000
> [1][5] = 10000263340
> [1][6] = 57 = 57
>= eg_probe sqep=177
>= eg_probe ind=3398635
>= eg_probe v=32749
>< eg_probe q=39
>
>EGTB value = 39 = #18
>
>[Don't worry about those large numbers above, they are meaningless]
>While our programs agree on the EGTB to use (24) they do not agree about the
>calculated index to use: yours=1557728, mine=3398635.
>[My sqep above is octal, the other values are decimal.]
>
>Hope this helps.
>Heiner
Yes, you are right. I was hurry to post, because I had to go out of home for a
while and I felt I needed some help for my return.
Of course, after Kh6 the postion is lost, but anyway, I get -mate in 1, which
is not correct.
Additionally, Dieter's post in Winboard Forum shows he gets the same number as
you.
Here my data:
rgiCounters={1,0,1,0,0,0,0,0,0,0}
psqW={0,55,0,34,0,0,21}
psqB={0, 0,0, 0,0,0,23}
iTb=24
side=0
sqEnP=127 (XX)
fInvert=0
ind=1557728 (?????????????????)
Result=32766
Correct numbers (before ind)?
José C.
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