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Subject: mate question

Author: Jan K.

Date: 11:26:17 08/22/04


hi....i need some help....my engine seems to have a problem in positions like
this one from WAC
[D]r3kb1r/1pp3p1/p3bp1p/5q2/3QN3/1P6/PBP3P1/3RR1K1 w kq - 0 1

with extensions:
depth|score(mate is 90)|time|nodes
4 89.91 0.077 30855 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8
4 -> 89.91 0.087 38970 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8
5 89.91 0.173 65972 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8
5 -> 89.91 0.429 191252 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8
6 89.91 0.688 319235 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8
6 -> 89.91 1.709 1037226 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8
7 89.91 2.379 1664198 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8
7 -> 89.91 7.369 5421612 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8
8 89.91 10.524 7943967 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8
8 -> 89.91 37.778 30229615 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8
9 89.91 50.168 41272010 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8
9 -> 89.91 197.056 164908328 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8

without extensions:
4 -0.23 0.005 1822 e4f6 e8f7 f6d7 f5g6
4 -0.04 0.023 11768 e4g5 f8c5 e1e6 f5e6 g5e6 c5d4 b2d4 f7g6 d7c7
4 1.66 0.031 16900 e4g3 f8c5 g3f5 c5d4 b2d4 c5d4 b2d4 f7g6 d7c7
4 -> 1.66 0.046 24667 e4g3 f8c5 g3f5 c5d4 b2d4 c5d4 b2d4 f7g6 d7c7
5 1.65 0.057 29693 e4g3 f5c5 e1e6 e8f7 d1e1 c5d4 b2d4 c5d4 g1f1 f7e6 d1d4
5 -> 1.65 0.088 55230 e4g3 f5c5 e1e6 e8f7 d1e1 c5d4 b2d4 c5d4 g1f1 f7e6 d1d4
6 1.65 0.101 62020 e4g3 f5c5 e1e6 e8f7 d1e1 c5d4 b2d4 c5d4 g1f1 f7e6 d1d4
6 -> 1.65 0.390 155803 e4g3 f5c5 e1e6 e8f7 d1e1 c5d4 b2d4 c5d4 g1f1 f7e6 d1d4
7 1.20 0.417 173599 e4g3 f5c5 e1e6 e8f7 e6e1 f8d6 g3e4 c5d4 b2d4 c7d6 g1f1
7 -> 1.20 0.892 417173 e4g3 f5c5 e1e6 e8f7 e6e1 f8d6 g3e4 c5d4 b2d4 c7d6 g1f1
8 1.15 0.988 467803 e4g3 f5c5 e1e6 e8f7 d1e1 c5d4 b2d4 f8d6
8 -> 1.15 2.100 1162258 e4g3 f5c5 e1e6 e8f7 d1e1 c5d4 b2d4 f8d6
9 1.17 2.230 1265171 e4g3 f5c5 e1e6 e8f7 d1e1 c5d4 b2d4 f8b4 e1e2
9 89.91 4.461 3217154 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8
9 -> 89.91 12.078 13306454 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8
10 89.91 14.649 14632878 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8
10 -> 89.91 120.830 132491936 d4d7 e6d7 e4d6 e8d8 d6f7 d8c8 e1e8 d7e8 d1d8

If I don't stop search after I found a mate and want to continue, is it normal
to get such a high branching factor? Note that 80% of time needed to complete an
iteration is consumed by searching remaining moves, although alfa at root is
near to beta thanks to the mate score(and I use pvs)...that doesn't look right
to me...and engines like Gothmog,Fruit,Aristarch seem to continue searching very
quickly. Where could be the problem? Are they using some kind of mate pruning?
:) Thanks.



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