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Subject: Re: Fast DEATH!

Author: Grzegorz Sidorowicz

Date: 01:13:21 06/28/02

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On June 27, 2002 at 10:50:33, Georg v. Zimmermann wrote:

>Dont be too disapointed, this is not that simple ! My program needs almost 2mill
>nodes to switch from xc6 to xf3 and almost 4mill for d4.
>
>Do you use threat-extensions ? Should help here. Can you print out subtrees your
>program searched ? That helps _a lot_. Null Move might be a problem here (1.xc6
>Qg5 2. g3 Qh5 3. Bxf7+ Kxf7 4.Qxc7+ Kg8 5.h4 Qg4 6.null Qh3 7.null, just
>guessing) .

When I not use NULL_MOVE...

7     10      1193981     144     b7c6 d8g5 g2g3 g5f6 c6c7 f6d8 c7d8
8     24      2718604     119     b7c6 d8g5 g2g3 g5g4 c6c7 g4h3 d5f7 f8f7 d2d4
8     45      5346462     142     d2d4 f3g2 g1g2 d8d7 f2f3 c6a5 b7a8 f8a8
9     2.26    17985432    117     d2d4 a8b8 b7c6 f3e2 d4c5 e2b5 c1g5 d8g5 c6b5
9     23.13   150477475   59      d2d4 a8b8 b7c6 f3e2 d4c5 e2b5 c1g5 d8g5 c6c7

...my program see it at depth 8 after 45 seconds. Problem is probably
in NULL_MOVE, but where?

With NULL_MOVE at depth 10 my program see it, but 4mill it is much smaller tree
than
15 mill

depth time    nodes       score   variation
-------------------------------------------
9     23      2264111     132     b7c6 d8g5 g2g3 g5e7 b2b4 c5b6 c6a8 f8a8 d5a8
                                  f7f5 d2d3
10    49      4911953     107     b7c6 d8g5 g2g3 g5f6 b2b4 c5b6 c6a8 f8a8 d5a8
                                  f3e2 d2d4 e2f1
10    2.11    12512489    -109    b7c6 d8g5 g2g3 g5g4 d5f7 g8f7 c6c7 f7g8 b2b4
                                  a8c8 c7e7
10    2.41    15901978    72      d2d4 a8b8 b7c6 f3e2 d4c5 e2b5 c1g5 d8g5 c6c7
                                  b5f1
11    4.55    29943763    47      d2d4 a8b8 b7c6 f3e2 d4c5 e2b5 c1g5 d8c8 c6b5
                                  b8b5 c5d6 c7d6 d5f7

Crafty, Hiarcs, Phalanx, CM8000 can find solution very very fast.

What is threat-extension? When it is used?
It is used for some moves from transposition table?

Grzegorz



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