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Subject: Re: WAC 141 blowup

Author: Andrew Platt

Date: 11:09:22 09/02/04

Go up one level in this thread


On September 02, 2004 at 09:45:25, Michael Henderson wrote:

>>>With pruning by evaluation latest movei get it only in 10 plies but I think to
>>>change my pruning to make it see it faster.
>>>
>>>Uri
>
>is recapture extension also playing a role here?...if that applies.

Having shaken some bugs out I'm now trying to understand where else my search
needs to be improved to get this in a reasonable time and re-capture seems to be
a key item. I played around with Crafty a bit and disabled re-capture extensions
(I left mate threat extensions in). Without re-capture things look like this:

                9     7.09  -0.88   1. Kf1 a5 2. Rxh5 gxh5 3. Rxh5 Re1+
                                    4. Kxe1 Nxh5 5. Qg5+ Kf8 6. Qh6+ Ke8
                                    7. Qh8+ Bf8 8. Qxh5
                9     8.23     +1   1. Qxf4!!
                9     8.56     +3   1. Qxf4!!
                9     9.24     +M   1. Qxf4!!
                9    41.38  10.88   1. Qxf4 Be5 2. dxe5 Rxe5 3. Bxe5 Qb6
                                    4. Rd1 Re7 5. Rd6
                9->  41.38  10.88   1. Qxf4 Be5 2. dxe5 Rxe5 3. Bxe5 Qb6
                                    4. Rd1 Re7 5. Rd6
               10    51.88     +1   1. Qxf4!!
               10     1:05     +3   1. Qxf4!!
               10     1:22     +M   1. Qxf4!!
               10     6:22  Mat06   1. Qxf4 Bxf4 2. Rxh5 gxh5 3. Rxh5 Bh6
                                    4. Rxh6 Qh2+ 5. Kxh2 Kf8 6. Rh8#
               10->   6:22  Mat06   1. Qxf4 Bxf4 2. Rxh5 gxh5 3. Rxh5 Bh6
                                    4. Rxh6 Qh2+ 5. Kxh2 Kf8 6. Rh8#


compared to this with both extensions (sorry about the switch from native output
to xboard output):

         9    -88     659 4040010  1. Kf1 a5 2. Rxh5 gxh5 3. Rxh5 Re1+ 4. Kxe1 N
xh5 5. Qg5+ Kf8 6. Qh6+ Ke8 7. Qh8+ Bf8 8. Qxh5
         9    -77     742 4591270  1. Qxf4!!
         9     23     779 4824187  1. Qxf4!!
         9    223     862 5373878  1. Qxf4!!
         9  32756    6672 48787620  1. Qxf4 Bxf4 2. Rxh5 gxh5 3. Rxh5 Bh6 4. Rxh
6 Qh2+ 5. Kxh2 Kf8 6. Rh8#
         9  32756    6672 48788236  1. Qxf4 Bxf4 2. Rxh5 gxh5 3. Rxh5 Bh6 4. Rxh
6 Qh2+ 5. Kxh2 Kf8 6. Rh8#


Andy.



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