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Subject: Re: Shredder 7.04 6 Piece EGTBs?

Author: Drexel,Michael

Date: 08:53:11 01/15/04

Go up one level in this thread


On January 15, 2004 at 10:26:37, Mike Hood wrote:

>On January 15, 2004 at 07:56:05, Drexel,Michael wrote:
>
>>On January 15, 2004 at 07:41:22, Mike Hood wrote:
>>
>>>On January 15, 2004 at 04:17:34, Drexel,Michael wrote:
>>>
>>>>On January 14, 2004 at 18:57:50, Mike Hood wrote:
>>>>
>>>>>On January 14, 2004 at 16:08:24, David H. McClain wrote:
>>>>>
>>>>>>On January 14, 2004 at 15:07:39, Chris Taylor wrote:
>>>>>>
>>>>>>>Does S8 know how to use the 6 piece egtbs'?  I could wait for it to arrive, nah;
>>>>>>>please tell me!  I have ordered the dam things and would like to know if I have
>>>>>>>wasted my GBPs.
>>>>>>>
>>>>>>>
>>>>>>>Chris
>>>>>>
>>>>>>Chris,
>>>>>>
>>>>>>Being an amatuer here perhaps I am making an incorrect assumption about this.
>>>>>>
>>>>>>When I use my Shredder 7.04 the heavy hard drive activity appears to indicate it
>>>>>>is accessing EGTBs tablebases when there are six pieces left on the board.  I
>>>>>>have assumed all along that this indicates that Shredder 7.04 is using a few of
>>>>>>my 6 piece EGTBs or is at least looking for them.  Shredder Classic GUI also
>>>>>>states "6 piece EGTBs found" when changing hash table size for them.
>>>>>>
>>>>>>Hopefully one of our experts on this can either confirm or refute this.  If this
>>>>>>is in fact true then I see no reason why S 8 would not do the same.
>>>>>>
>>>>>>DHM
>>>>>
>>>>>The disk activity (and the "tb=" info in the engine window) when 6 pieces are on
>>>>>the board doesn't necessarily mean that Shredder 7 is accessing a 6-piece
>>>>>tablebase. It might only be accessing 5-piece tablebases in a search line which
>>>>>results in the capture of one of the pieces.
>>>>>
>>>>>As far as I know, Shredder 7 accesses the single part 6-piece tablebases, ie the
>>>>>tablebases that don't have a digit in the filename. The only programs that I
>>>>>know that access the multi-part 6-piece tablebases are Hiarcs 9 and Crafty. I
>>>>>assume that Shredder 8 can be added to this list. Ask me again next week.
>>>>
>>>>You can add Fritz 7 and Fritz 8 to that list.
>>>>
>>>>Michael
>>>
>>>Sorry, Michael, you're wrong.
>>
>>No, I am right. Both Fritz 7 and Fritz 8 use them in the search.
>>
>>New game
>>3kr3/8/8/8/8/3p4/2PP4/2RK4 w - - 0 1
>>
>>Analysis by Fritz 7:
>>
>>1. = (0.00): 1.Ta1 dxc2+ 2.Kxc2 Te2 3.Ta7 Te1
>>2. = (0.00): 1.Tb1 dxc2+ 2.Kxc2 Te2
>>3. = (0.00): 1.cxd3 Te5 2.d4 Td5
>>4. -+ (-#28): 1.c3 Th8 2.Ke1
>>5. -+ (-#21): 1.c4 Tg8 2.Ke1
>>
>>
>>New game
>>3kr3/8/8/8/8/3p4/2PP4/2RK4 w - - 0 1
>>
>>Analysis by Fritz 8:
>>
>>1. = (0.00): 1.cxd3 Kd7
>>2. = (0.00): 1.Ta1 dxc2+ 2.Kxc2
>>3. = (0.00): 1.Tb1 dxc2+ 2.Kxc2
>>4. -+ (-#27): 1.c3 Tg8 2.Ke1 Tg1+ 3.Kf2 Txc1 4.Ke3 Te1+ 5.Kd4 Te2 6.Kxd3
>>5. -+ (-#21): 1.c4 Th8 2.Ke1 Th1+ 3.Kf2 Txc1 4.Ke3 Txc4 5.Kxd3 Tc1 6.Kd4
>>
>>
>>This is what you get if an engine does not use them:
>>
>>New game
>>3kr3/8/8/8/8/3p4/2PP4/2RK4 w - - 0 1
>>
>>Analysis by Fritz 6:
>>
>>1. ± (1.38): 1.cxd3 Kd7 2.Tc5 Kd6 3.Ta5 Kc6 4.d4 Te4 5.d5+ Kb6
>>2. = (0.00): 1.Tb1 dxc2+ 2.Kxc2
>>3. = (0.00): 1.Ta1 dxc2+ 2.Kxc2
>>4. -+ (-#27): 1.c3 Th8 2.Ke1 Th1+ 3.Kf2 Txc1 4.Ke3 Te1+ 5.Kd4 Te2
>>5. -+ (-#21): 1.c4 Th8 2.Ke1 Th1+ 3.Kf2 Txc1 4.Ke3 Txc4
>>
>>Michael
>
>Michael, these analyses don't prove anything. When you analyse parallel lines,
>Fritz doesn't display the "tb=" info which is needed for proof. Also, in order
>to carry out the test you need to remove all the 5-piece, 4-piece and 3-piece
>tablebases before starting Fritz. I can guarantee you that the Fritz 7 and Fritz
>8 engines (Fritz 8.0.0.23) don't access multi-part tablebases. However, Fritz 7
>and Fritz 8 do access single-part 6-piece tablebases.

The tb info is no proof at all. It is also not needed for a proof. Just look at
the evaluation.
If Fritz 7 don't access multi-part tablebases please explain this:

[D] 8/7k/6rq/8/8/7Q/6PP/6KR w - - 0 9

tbtest
8/7k/6rq/8/8/7Q/6PP/6KR w - - 0 1

Analysis by Fritz 7:

9.Dxh6+ Kg8 10.Dxg6+ Kh8 11.Df6+ Kh7 12.h4 Kg8
  +-  (16.41)   Depth: 5/13   00:00:00  6kN, tb=8
9.Dxh6+!
  +-  (16.75)   Depth: 6/10   00:00:00  6kN, tb=10
9.Dxh6+!
  +-  (17.06)   Depth: 7/13   00:00:00  14kN, tb=14
9.Dxh6+!
  +-  (17.06)   Depth: 7/13   00:00:00  14kN, tb=14
9.Dxh6+!
  +-  (#41)   Depth: 7/18   00:00:00  23kN, tb=21
9.Dxh6+!
  +-  (#41)   Depth: 7/18   00:00:00  28kN, tb=27

And explain me why Fritz 7 blunders its Qeen in this position:

[D] 7k/8/6Q1/8/8/8/6PP/6KR w - - 0 11

7k/8/6Q1/8/8/8/6PP/6KR w - - 0 1

Analysis by Fritz 7:

11.Dg8+ Kxg8 12.h4 Kg7 13.g4
  +-  (#12)   Depth: 7/15   00:00:00  31kN, tb=11

Michael



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