Author: José Carlos
Date: 14:23:13 10/28/01
Go up one level in this thread
On October 28, 2001 at 17:12:30, Heiner Marxen wrote:
>On October 28, 2001 at 15:37:09, José Carlos wrote:
>
>>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
>
>Correction: the above numbers are octal, i.e. 17-->h2, 32-->c4 55->f6 57->h6
>
>>>= 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}
>
>Ha! Here is the problem. Assuming that you show decimal numbers, it makes
>sense, but you got it upside/down, i.e. you count a8 as 0, h8 as 7,
>a7 as 8 etc, whereas you are supposed to start with a1=0, h1=7, a2=8 etc.
>
>What you asked effectively was
>[D]8/7P/8/2B5/8/5K1k/8 w - -
>
>which in fact is mate in 1.
>Just flip the rows, and you should get some correct answers.
>
>From your followup I see that you like my coding trick :-)
>As far as I have tested it with Chest it seems to work quite well,
>so that should not be the problem.
>
>Happy EGTB probing!
>Heiner
>
>
>> iTb=24
>> side=0
>> sqEnP=127 (XX)
>> fInvert=0
>> ind=1557728 (?????????????????)
>> Result=32766
>>
>> Correct numbers (before ind)?
>>
>> José C.
Thank you Heiner. I solved it looking at your numbers, just a minute after
posting mine :)
Yes, I do like your trick. Works nicely. I must admit I didn't understand all
your code, but it gave me exactly what I needed: a starting point. Something to
begin with. And in one day (today) I've been able to do what I thought it was
impossible :)
José C.
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