Author: GeoffW
Date: 16:56:30 09/01/04
Go up one level in this thread
On September 01, 2004 at 18:20:20, Robert Hyatt wrote:
>On September 01, 2004 at 00:51:47, Stuart Cracraft wrote:
>
>>I know this is a long shot throwing this out there without much more
>>info, but perhaps I'll get lucky and someone has seen this before.
>>It's appeared on this bulletin board about 6 years ago.
>>
>>[D]4r1k1/p1qr1p2/2pb1Bp1/1p5p/3P1n1R/1B3P2/PP3PK1/2Q4R w - - bm Qxf4; id
>>"WAC.141";
>>
This was an interesting post as I have just been adding mate threat extensions
to my program and fixing a bug or several at the same time.
One of the things I noticed that was a little puzzling was the +2
if (value == -MATE + ply + 2)
mate_threat = 1;
For my program it needs to be +1 to make this work correctly. I discussed this
with Ross (Trace) and it was +1 for him too, yet for Stuart and Crafty that
needs to be +2, still havent explained that one ?
The thing I cant decide now is have I implemented this correctly without a bug ?
From my results it seems that it could be correct, but the search explosion is
very bad at deeper ply (compared to Bobs quoted figures )
Maybe the threat extension code is OK, but just highlighting my poor move
ordering ?
Any thoughts would be appreciated
here are my results
check extensions, but no mate threat extensions
Ply Eval Time Nodes Principle Variation
9 -151 606 5753869 g2f1 e8c8 c1b1 f4d5 h1g1 d6f4 b3d5 d7d5 f1e1
10+ -106 1456 14387871 g2f1
10+ 194 2910 29451052 g2f1 g8f8 h4h5 g6h5 h1h5 e8e1 f1e1 f4h5 c1h6 f8e8
h6h8 d6f8 h8h5 f8b4 e1d1
10 9989 4514 49522394 c1f4 d6f4 h4h5 g6h5 h1h5 f4h6 h5h6 c7h2 h6h2 g8f8
h2h8
Computer's move: c1f4
check extensions, and mate threat extensions
6 -210 10 106899 g2f1 a7a5 f6e5 f4d3 c1g5 d3e5 d4e5 d6e5 g5g6
7 -203 48 462385 g2f1 e8e2 c1b1 d6e7 h4f4 c7f4 f1e2 f4f6
8+ -158 214 2114011 g2f1 e8e2 c1b1 e2d2 f6g5 d2d4 g5f4 d6f4 b1g6
8+ 142 237 2343262 c1f4
8 94 290 2904048 c1f4 e8e6 h4h5 g6h5 f4g5 g8f8 b3e6 f7e6 g5h5
9+ 139 337 3307392 c1f4
9+ 439 521 5024678 c1f4
9 462 810 7874059 c1f4 e8e6 f4g5 d6e7 b3e6 e7f6 g5g6 f6g7 e6b3 a7a5
g6h5 d7d4 h4d4 g7d4
10+ 507 1128 10950029 c1f4
10+ 807 1945 19089764 c1f4
10 9989 10639 144085366 c1f4 d6f4 h4h5 g6h5 h1h5 f4h6 h5h6 c7g3 g2g3 a7a5
h6h8
Computer's move: c1f4
Geoff
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