Author: Steffen Basting
Date: 10:14:51 08/10/02
Hello!
I've got 2 questions about principal variations:
1.) How do I receive the principal variation in my alpha-beta algorithm?
(I read the "tutorial" on Bruce Morelands page but didn't understand it :-)
Are there more than 1 possibilities to handle that?
2.) Why do programs sometimes show "shorter" principal variations compared to
depth? For example this output from an analysis with Little Goliath on the
position Eduard posted:
2r1r1kb/5p2/p3pQpB/1p1pP3/3p2P1/n1q2B2/2P2PK1/4R2R b - - 0 1
Analysis by Little Goliath 2000 v3.6:
1...Lxf6 2.exf6 Sxc2 3.Tc1
-+ (-13.72) Tiefe: 6/10 00:00:07 7kN
1...Lxf6 2.exf6 Sxc2 3.Tc1
-+ (-14.03) Tiefe: 7/13 00:00:07 16kN
1...Lxf6 2.exf6 Sxc2 3.Td1 d3 4.Lg7 a5
-+ (-14.20) Tiefe: 7/14 00:00:07 24kN
1...Lxf6 2.exf6 Sxc2 3.Td1 d3 4.Lg7 a5
-+ (-13.90) Tiefe: 8/16 00:00:08 94kN
1...Lxf6 2.exf6
-+ (-13.91) Tiefe: 8/16 00:00:08 96kN
1...Lxf6 2.exf6 Sxc2 3.Td1 a5 4.Ld2 Da3 5.Tb1
-+ (-13.62) Tiefe: 9/19 00:00:08 351kN
1...Lxf6 2.exf6 Sxc2 3.Td1 a5 4.Ld2 Da3 5.Tb1
-+ (-13.32) Tiefe: 10/23 00:00:10 1307kN
1...Lxf6 2.exf6 Sxc2 3.Td1 Se3+ 4.fxe3 dxe3 5.Tde1 Dxf6 6.Lxe3 Tc2+ 7.Te2 Txe2+
8.Lxe2 d4
-+ (-12.37) Tiefe: 10/25 00:00:11 2844kN
1...Lxf6 2.exf6 Sxc2 3.Td1 Se3+ 4.fxe3 dxe3 5.Tde1 Dxf6 6.Lxe3 Tc2+ 7.Te2 Txe2+
8.Lxe2 d4
-+ (-12.67) Tiefe: 11/28 00:00:13 4397kN
1...Lxf6 2.exf6 Sxc2 3.Td1 Se3+ 4.fxe3 dxe3 5.Tde1 Dxf6 6.Lxe3 Tc2+ 7.Te2 Txe2+
8.Lxe2 d4
-+ (-13.47) Tiefe: 11/28 00:00:13 4443kN
1...Lxf6
-+ (-13.47) Tiefe: 11/28 00:00:15 6102kN
1...Lxf6
-+ (-13.17) Tiefe: 12/28 00:00:16 8207kN
1...Lxf6 2.exf6
-+ (-13.19) Tiefe: 12/28 00:00:17 8464kN
1...Lxf6 2.exf6
-+ (-12.89) Tiefe: 13/28 00:00:22 14553kN
1...Lxf6 2.exf6 Dxe1 3.Txe1 Sxc2 4.Th1 g5 5.Le2 Tc3 6.Lxg5 d3 7.Ld2 dxe2 8.Lxc3
d4
-+ (-7.94) Tiefe: 13/32 00:00:42 34272kN
1...Sxc2
-+ (-8.10) Tiefe: 13/38 00:01:09 74800kN
1...Sxc2 2.Dxh8+ Kxh8 3.Lg5+ Kg8 4.Lf6 Sxe1+ 5.Kf1 Dd3+ 6.Le2 Dxe2+ 7.Kxe2 Tc2+
8.Kd1
-+ (-8.09) Tiefe: 13/38 00:01:14 80352kN
1...Sxc2 2.Dxh8+ Kxh8 3.Lg5+ Kg8 4.Lf6 Sxe1+ 5.Kf1 Dd3+ 6.Le2 Dxe2+ 7.Kxe2 Tc2+
8.Kd1
-+ (-7.79) Tiefe: 14/38 00:01:15 81852kN
1...Sxc2 2.Dxh8+ Kxh8 3.Lg5+ Kg8 4.Lf6
+- (#11) Tiefe: 14/38 00:01:25 91674kN
1...Lxf6
= (0.11) Tiefe: 14/38 00:01:25 92101kN
1...Lxf6 2.exf6 Dxe1 3.Txe1 Sxc2 4.Th1 Se1+ 5.Txe1 Tc3 6.Lg7 Txf3 7.Kxf3 Tc8
8.Th1 Tc3+ 9.Ke2 d3+
-+ (-1.83) Tiefe: 14/44 00:07:15 446358kN
1...Lxf6 2.exf6 Dxe1 3.Txe1 Sxc2 4.Th1 Se1+ 5.Txe1 Tc3 6.Lg7 Txf3 7.Kxf3 Tc8
8.Th1 Tc3+ 9.Ke2 d3+
-+ (-1.53) Tiefe: 15/47 00:10:14 728548kN
1...Lxf6 2.exf6
-+ (-1.64) Tiefe: 15/47 00:10:15 728594kN
1...Lxf6 2.exf6
-+ (-1.94) Tiefe: 16/47 00:13:59 1042841kN
1...Lxf6 2.exf6 Dxe1 3.Txe1 Sxc2
-+ (-1.93) Tiefe: 16/47 00:14:55 1131809kN
1...Lxf6 2.exf6 Dxe1 3.Txe1 Sxc2
-+ (-1.63) Tiefe: 17/47 00:22:08 1840673kN
1...Lxf6 2.exf6
-+ (-1.64) Tiefe: 17/47 00:22:11 1845920kN
What I mean is: Why doesn't the principal variation have a length of 16 plies at
depth 16 although the search for this depth is finished while it has got a
length of 7 plies at Depth 7 (for example)?
Thanks for your responses, Steffen
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