Question regarding WAC number 2

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jacobbl
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Joined: Wed Feb 17, 2010 2:57 pm

Question regarding WAC number 2

Post by jacobbl » Mon Oct 18, 2010 2:46 pm

Hi, I notice that all strong engine have no problem in reaching the correct solution for WAC number 2 in less than a second:

8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - - bm b3b2;

My engine uses much more time on this problem, because it has to search quite deep to find the solution.

I'm wondering if this is a problem which should be solved through more use of extensions (I'm using check extensions today), or should it be solved in the quiescent search or should the evalution function be able to value the position high enough before the pawns have queened?

Regards
Jacob Børs Lind

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opraus
Posts: 166
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Location: S. New Jersey, USA
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Re: Question regarding WAC number 2

Post by opraus » Mon Oct 18, 2010 3:18 pm

xpdnt finds it in 5 second on a 2Ghz machine.
It uses only check extension.
but ...
It does NOT reduce passer moves to 6th and 7th rank. And,
It also gives bonus to 'connected passers' in eval.

'pawns on the 6th rank beat a rook' - W.JORDAN MELBOURNE 1997

Uri Blass
Posts: 8530
Joined: Wed Mar 08, 2006 11:37 pm
Location: Tel-Aviv Israel

Re: Question regarding WAC number 2

Post by Uri Blass » Mon Oct 18, 2010 8:32 pm

jacobbl wrote:Hi, I notice that all strong engine have no problem in reaching the correct solution for WAC number 2 in less than a second:

8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - - bm b3b2;

My engine uses much more time on this problem, because it has to search quite deep to find the solution.

I'm wondering if this is a problem which should be solved through more use of extensions (I'm using check extensions today), or should it be solved in the quiescent search or should the evalution function be able to value the position high enough before the pawns have queened?

Regards
Jacob Børs Lind
I notice that not all the strong engines do it
stockfish1.9 needs depth 21 and 8 seconds probably because it does too much pruning.

New game
8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - - 0 1

Analysis by Stockfish 1.9 JA:

1...Rb3-b8
µ (-1.37) Depth: 1 00:00:00
1...Rb3-b7 2.e3-e4
µ (-1.21) Depth: 2 00:00:00
1...Rb3-b7 2.e3-e4 Kf6-e6
µ (-1.21) Depth: 3 00:00:00
1...Kf6-e6 2.e3-e4 Rb3-b8
µ (-1.25) Depth: 3 00:00:00
1...Kf6-e6 2.e3-e4 Rb3-b8 3.e4-e5
µ (-1.17) Depth: 4 00:00:00
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3
µ (-1.29) Depth: 4 00:00:00
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3
µ (-1.29) Depth: 5 00:00:00
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3
µ (-1.13) Depth: 6 00:00:00 1kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3
µ (-1.13) Depth: 6 00:00:00 2kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4
µ (-1.09) Depth: 6 00:00:00 2kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.f4-f5+ Ke6-f6
µ (-1.09) Depth: 7 00:00:00 5kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.f4-f5+ Ke6-f6
µ (-1.21) Depth: 8 00:00:00 7kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.f4-f5+ Ke6-f6
µ (-1.09) Depth: 8 00:00:00 8kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.f4-f5+ Ke6-f6
µ (-1.17) Depth: 9 00:00:00 10kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.f4-f5+ Ke6-f6
µ (-1.25) Depth: 9 00:00:00 11kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 Kf6-e6 5.e4-e5 Ra3-b3 6.Rd2xd3 Rb3xd3+ 7.Ke3xd3 a4-a3
-+ (-1.41) Depth: 9 00:00:01 12kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.Rd2xd3 Ra3xd3 7.Ke4xd3 a4-a3
-+ (-1.73) Depth: 9 00:00:01 14kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.Rd2xd3 Ra3xd3 7.Ke4xd3 a4-a3 8.Kd3-c4 Ke6-f6
-+ (-1.73) Depth: 9 00:00:01 15kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.Rd2xd3 Ra3xd3 7.Ke4xd3 a4-a3 8.Kd3-c3 Ke6-f6 9.Kc3-b3
µ (-1.09) Depth: 10 00:00:01 21kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.Rd2-d1 Ra3-b3 7.Rd1xd3 Rb3xd3 8.Ke4xd3 a4-a3 9.Kd3-c3 Ke6-f6 10.Kc3-b3
µ (-1.13) Depth: 10 00:00:01 27kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.Rd2xd3 Ra3xd3 7.Ke4xd3 a4-a3 8.Kd3-c3 a3-a2 9.Kc3-b2 Ke6-f5 10.Kb2xa2 Kf5xf4
³ (-0.68) Depth: 11 00:00:01 59kN
1...Kf6-e6 2.e3-e4 f5xe4+ 3.Kf3xe4 Rb3-b8 4.Ke4-d4 Rb8-c8 5.Kd4-e4 Ke6-f6 6.h2-h4 h7-h5 7.Rd2-g2 Rc8-e8+ 8.Ke4-d4 Re8-e2 9.Rg2-g1
µ (-1.05) Depth: 11 00:00:01 76kN
1...Kf6-e6 2.e3-e4 f5xe4+ 3.Kf3xe4 Rb3-b8 4.Ke4-d4 Rb8-c8 5.Kd4-e4 Rc8-f8 6.Rd2-d1 Ke6-d6 7.f4-f5 Kd6-c5 8.Rd1-d2 Rf8-e8+ 9.Ke4-f3 Kc5-d5 10.f5-f6 Re8-b8
µ (-0.96) Depth: 12 00:00:01 149kN
1...Rb3-b8 2.h2-h4 Rb8-b3 3.e3-e4 f5xe4+ 4.Kf3xe4 Rb3-b8 5.Rd2-g2 Rb8-e8+ 6.Ke4-d4 Re8-e2 7.Rg2-g1 d3-d2 8.Rg1-d1 Kf6-f5 9.Kd4-c3
µ (-1.21) Depth: 12 00:00:01 218kN
1...Rb3-b7 2.Rd2-g2 Rb7-b8 3.Rg2-d2 Rb8-e8 4.Rd2-d1 h7-h5 5.Rd1-c1 Re8-b8 6.Rc1xc4 Rb8xb2 7.Rc4-c6+ Kf6-e7
µ (-1.25) Depth: 12 00:00:01 256kN
1...Rb3-b7 2.Rd2-g2 Rb7-b8 3.h2-h3 Rb8-b3 4.Rg2-d2 Rb3-b7 5.Rd2-g2 Rb7-g7 6.Rg2xg7 Kf6xg7 7.e3-e4 Kg7-f6 8.Kf3-e3 f5xe4 9.Ke3xe4
µ (-1.29) Depth: 13 00:00:01 323kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.h2-h4 Rb7-e7+ 6.Ke4-d4 Kf6-f5 7.Kd4xc4 Re7-e2 8.Rg2-g1 Kf5-e4 9.Rg1-d1 Re2-c2+ 10.Kc4-b4 Rc2xb2+ 11.Kb4xa4
µ (-1.37) Depth: 14 00:00:01 426kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-c3 Kf6-f5 7.Rg2-f2 Rd7-e7 8.Kc3xc4 Re7-e2 9.Rf2-f1 d3-d2 10.Rf1-d1 Kf5xf4 11.Kc4-d3
µ (-1.25) Depth: 15 00:00:01 598kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-c3 Kf6-f5 7.Rg2-f2 Rd7-e7 8.Kc3xc4 Re7-e2 9.Rf2-f1 d3-d2 10.Rf1-d1 Kf5xf4 11.Kc4-d3
-+ (-1.49) Depth: 15 00:00:02 727kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-c3 Kf6-f5 7.Rg2-f2 Kf5-e4 8.Rf2-f1 Rd7-b7 9.f4-f5 Ke4-d5 10.Rf1-b1 h7-h5
µ (-1.25) Depth: 15 00:00:02 736kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-c3 Kf6-f5 7.Rg2-f2 Kf5-e4 8.Rf2-f1 Rd7-b7 9.f4-f5 Ke4-d5 10.Rf1-b1 Rb7-b3+ 11.Kc3-d2 Kd5-e4
-+ (-1.41) Depth: 16 00:00:02 820kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-c3 Kf6-f5 7.Rg2-f2 Kf5-e4 8.Rf2-f1 Rd7-b7 9.f4-f5 Ke4-d5 10.Rf1-b1 Rb7-b3+ 11.Kc3-d2 Kd5-e4 12.Rb1-e1+ Ke4xf5 13.Re1-f1+ Kf5-e4 14.Rf1-e1+ Ke4-d4
-+ (-1.53) Depth: 16 00:00:02 951kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-e3 Rd7-e7+ 7.Ke3-f3 Re7-e1 8.h2-h4 Kf6-e6 9.h4-h5 Ke6-f6 10.h5-h6 Kf6-f5 11.Rg2-g5+ Kf5-e6 12.Rg5-g2 Ke6-d5 13.Rg2-d2
-+ (-1.65) Depth: 17 00:00:02 1407kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-c3 Kf6-f5 7.Rg2-f2 Kf5-e4 8.Rf2-f1 Rd7-b7 9.f4-f5 Ke4-d5 10.Rf1-b1 Rb7-b3+ 11.Kc3-d2 Kd5-e4 12.Rb1-e1+ Ke4xf5 13.Re1-f1+ Kf5-e4 14.Rf1-e1+ Ke4-d4
-+ (-1.53) Depth: 18 00:00:03 1715kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-c3 Kf6-f5 7.Rg2-f2 Kf5-e4 8.Rf2-f1 Rd7-b7 9.f4-f5 Ke4-d5 10.Rf1-b1 Rb7-b3+ 11.Kc3-d2 Kd5-e4 12.Rb1-e1+ Ke4xf5 13.Re1-f1+ Kf5-e4 14.Rf1-e1+ Ke4-d4
-+ (-1.73) Depth: 19 00:00:04 2426kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.h2-h3 Rb7-b3 4.Rg2-d2 Ke6-d5 5.Rd2-g2 c4-c3 6.b2xc3 Rb3xa3
-+ (-1.93) Depth: 19 00:00:04 3137kN
1...Rb3-b7 2.h2-h3 Rb7-g7 3.e3-e4 f5xe4+ 4.Kf3xe4 Rg7-e7+ 5.Ke4-d4 Re7-e2 6.Kd4-c3 Re2-e4 7.Rd2-g2 Re4xf4 8.Rg2-g8 Kf6-e6 9.Rg8-c8 Ke6-d5 10.Rc8-d8+ Kd5-c5 11.Rd8-c8+ Kc5-b5 12.Rc8-b8+ Kb5-c6 13.Rb8-b4 Kc6-d5 14.Rb4xa4
-+ (-1.81) Depth: 19 00:00:04 3947kN
1...Rb3-b7 2.e3-e4 f5xe4+ 3.Kf3xe4 Rb7-e7+ 4.Ke4-d4 Re7-e2 5.Kd4-c3 Re2-e4 6.Rd2-g2 Re4xf4 7.Rg2-g8 Rf4-h4 8.Rg8-c8 Kf6-f5 9.Rc8-c7 Kf5-e6 10.h2-h3 Ke6-d5 11.Rc7-a7 Rh4-h6 12.Ra7xa4
-+ (-1.73) Depth: 20 00:00:05 5536kN
1...Rb3-b7 2.e3-e4 f5xe4+ 3.Kf3xe4 Rb7-e7+ 4.Ke4-d4 Re7-e2 5.Kd4-c3 Re2-e4 6.Rd2-g2 Re4xf4 7.Rg2-g8 Rf4-e4 8.Rg8-f8+ Kf6-g5 9.Rf8-c8 Kg5-f4
-+ (-1.97) Depth: 21 00:00:07 6858kN
1...Rb3-b7 2.h2-h3 Rb7-g7 3.Rd2-d1 Kf6-e6 4.h3-h4 Ke6-d5 5.Rd1-h1 Rg7-g6 6.Rh1-f1 Rg6-b6 7.Rf1-f2 Rb6-h6 8.Rf2-h2 Rh6-g6 9.Rh2-h1 h7-h6 10.Rh1-d1 Rg6-g8 11.Rd1-h1 Rg8-g7 12.h4-h5 Rg7-g8 13.Rh1-d1 Rg8-b8
-+ (-2.06) Depth: 21 00:00:08 7881kN
1...Rb3xb2 2.Rd2xb2 c4-c3 3.Rb2-b6+ Kf6-g7 4.Rb6-b7+ Kg7-h6 5.Rb7-b6+ Kh6-h5 6.Rb6-f6 c3-c2 7.Rf6xf5+ Kh5-h6 8.Rf5-f6+ Kh6-g7 9.Rf6-c6 d3-d2 10.Rc6-c7+ Kg7-h6
-+ (-2.22) Depth: 21 00:00:08 8758kN
1...Rb3xb2 2.Rd2xb2 c4-c3 3.Rb2-b6+ Kf6-g7 4.Rb6-b7+ Kg7-h6 5.Rb7-b6+ Kh6-h5 6.Rb6-f6 c3-c2 7.Rf6xf5+ Kh5-h6 8.Rf5-f6+ Kh6-g7 9.Rf6-c6 d3-d2 10.Rc6-c7+ Kg7-h6
-+ (-2.70) Depth: 21 00:00:09 9390kN
1...Rb3xb2 2.Rd2xb2 c4-c3 3.Rb2-b6+ Kf6-g7 4.Rb6-b7+ Kg7-h6 5.Rb7-b6+ Kh6-h5 6.Rb6-f6 c3-c2 7.Rf6xf5+ Kh5-h6 8.Rf5-f6+ Kh6-g7 9.Rf6-c6 d3-d2 10.Rc6-c7+ Kg7-h6 11.Rc7-c6+ Kh6-h5 12.Rc6-c5+ Kh5-h4 13.Rc5xc2 d2-d1Q+ 14.Rc2-e2 Qd1-d3
-+ (-3.67) Depth: 21 00:00:10 10403kN

(, 18.10.2010)

jacobbl
Posts: 80
Joined: Wed Feb 17, 2010 2:57 pm

Re: Question regarding WAC number 2

Post by jacobbl » Mon Oct 18, 2010 9:09 pm

5 seconds is quite good. What depth do you need?

bob
Posts: 20406
Joined: Mon Feb 27, 2006 6:30 pm
Location: Birmingham, AL

Re: Question regarding WAC number 2

Post by bob » Mon Oct 18, 2010 9:51 pm

jacobbl wrote:Hi, I notice that all strong engine have no problem in reaching the correct solution for WAC number 2 in less than a second:

8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - - bm b3b2;

My engine uses much more time on this problem, because it has to search quite deep to find the solution.

I'm wondering if this is a problem which should be solved through more use of extensions (I'm using check extensions today), or should it be solved in the quiescent search or should the evalution function be able to value the position high enough before the pawns have queened?

Regards
Jacob Børs Lind
Hard to say. First, here is current Crafty's output on my core-2 laptop:

Code: Select all

               17     0.16  -1.33   1. ... c3 2. bxc3 Rxc3 3. Ra2 Rc2 4. 
                                    Ra1 Rb2 5. Rc1 Rb3 6. Rc6+ Ke7 7. Rc7+
                                    Kd6 8. Rxh7 Rxa3 9. Rh8 Ra2 10. Rd8+
                                    Kc5 11. Rxd3 Rxh2 (s=2)
               17     0.22     -1   1. ... Rxb2!                         
               17     0.23     -3   1. ... Rxb2!                         
               17     0.31  -3.77   1. ... Rxb2 2. Rxb2 c3 3. Rb6+ Kg7   
                                    4. Rb7+ Kg6 5. Rb6+ Kh5 6. Rb5 c2 7.
                                    Rxf5+ Kg6 8. Rg5+ Kf6 9. Rc5 d2 10.
                                    Rc6+ Ke7 11. Rc7+ Kd6 12. Rxc2 d1=Q+
                                    13. Re2 Qf1+ 14. Rf2
               17->   0.34  -3.77   1. ... Rxb2 2. Rxb2 c3 3. Rb6+ Kg7   
                                    4. Rb7+ Kg6 5. Rb6+ Kh5 6. Rb5 c2 7.
                                    Rxf5+ Kg6 8. Rg5+ Kf6 9. Rc5 d2 10.
                                    Rc6+ Ke7 11. Rc7+ Kd6 12. Rxc2 d1=Q+
                                    13. Re2 Qf1+ 14. Rf2 (s=2)
               18     0.41     -1   1. ... Rxb2!                         
               18     0.64     -3   1. ... Rxb2!                         
               18     0.81  -5.44   1. ... Rxb2 2. Rxb2 c3 3. Rb6+ Ke7   
                                    4. Rb7+ Kd6 5. Rb6+ Kc5 6. Rb1 c2 7.
                                    Rc1 Kb5 8. Kf2 d2 9. Rxc2 d1=Q 10.
                                    Rb2+ Kc4 11. Rb4+ Kc3 12. Rd4 Qc2+
                                    13. Kg3
               18->   0.82  -5.44   1. ... Rxb2 2. Rxb2 c3 3. Rb6+ Ke7   
                                    4. Rb7+ Kd6 5. Rb6+ Kc5 6. Rb1 c2 7.
                                    Rc1 Kb5 8. Kf2 d2 9. Rxc2 d1=Q 10.
                                    Rb2+ Kc4 11. Rb4+ Kc3 12. Rd4 Qc2+
                                    13. Kg3
               19     1.06  -5.48   1. ... Rxb2 2. Rxb2 c3 3. Rb6+ Ke7   
                                    4. Rc6 c2 5. Kf2 d2 6. Rxc2 d1=Q 7.
                                    Rc7+ Kd6 8. Rxh7 Qd2+ 9. Kf3 Qd5+ 10.
                                    Kf2 Qa2+ 11. Kf3 Qxa3 12. h4 Qa2 13.
                                    h5 Qd5+ 14. Ke2
It takes about 1/4 second to find the move. If you want to go to faster hardware,

Code: Select all

               17     0.04     -1   1. ... Rxb2!                         
               17     0.05     -3   1. ... Rxb2!                         
               17     0.05     -M   1. ... Rxb2!                         
               17     0.08  -5.21   1. ... Rxb2 2. Rxb2 c3 3. Rb6+ Ke7   
                                    4. Rb7+ Kd6 5. Rb6+ Kc7 6. Rb4 c2 7.
                                    Rc4+ Kd7 8. Kf2 d2 9. Rxc2 d1=Q 10.
                                    Rb2 Kc6 11. h4 Kc5
So for Crafty, with pretty aggressive null-move, aggressive LMR and aggressive forward pruning, it takes 17 plies. Several years ago it would solve this in 12 plies, although it would take significantly longer. The main problem with this position is those pesky rook checks that you have to walk your king out of before you can make progress. Yet they delay the two passed pawns just long enough to burn some time. The deeper you go, the easier this is to find. If your selectivity helps you get deeper, quickly, without overlooking the key moves, this one is pretty easy...

BTW search speed on my laptop is 6.5M nps for this position. The 8-core box is close to 30M.

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michiguel
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Re: Question regarding WAC number 2

Post by michiguel » Mon Oct 18, 2010 10:10 pm

Uri Blass wrote:
jacobbl wrote:Hi, I notice that all strong engine have no problem in reaching the correct solution for WAC number 2 in less than a second:

8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - - bm b3b2;

My engine uses much more time on this problem, because it has to search quite deep to find the solution.

I'm wondering if this is a problem which should be solved through more use of extensions (I'm using check extensions today), or should it be solved in the quiescent search or should the evalution function be able to value the position high enough before the pawns have queened?

Regards
Jacob Børs Lind
I notice that not all the strong engines do it
stockfish1.9 needs depth 21 and 8 seconds probably because it does too much pruning.

New game
8/7p/5k2/5p2/p1p2P2/Pr1pPK2/1P1R3P/8 b - - 0 1

Analysis by Stockfish 1.9 JA:

1...Rb3-b8
µ (-1.37) Depth: 1 00:00:00
1...Rb3-b7 2.e3-e4
µ (-1.21) Depth: 2 00:00:00
1...Rb3-b7 2.e3-e4 Kf6-e6
µ (-1.21) Depth: 3 00:00:00
1...Kf6-e6 2.e3-e4 Rb3-b8
µ (-1.25) Depth: 3 00:00:00
1...Kf6-e6 2.e3-e4 Rb3-b8 3.e4-e5
µ (-1.17) Depth: 4 00:00:00
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3
µ (-1.29) Depth: 4 00:00:00
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3
µ (-1.29) Depth: 5 00:00:00
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3
µ (-1.13) Depth: 6 00:00:00 1kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3
µ (-1.13) Depth: 6 00:00:00 2kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4
µ (-1.09) Depth: 6 00:00:00 2kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.f4-f5+ Ke6-f6
µ (-1.09) Depth: 7 00:00:00 5kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.f4-f5+ Ke6-f6
µ (-1.21) Depth: 8 00:00:00 7kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.f4-f5+ Ke6-f6
µ (-1.09) Depth: 8 00:00:00 8kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.f4-f5+ Ke6-f6
µ (-1.17) Depth: 9 00:00:00 10kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.f4-f5+ Ke6-f6
µ (-1.25) Depth: 9 00:00:00 11kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 Kf6-e6 5.e4-e5 Ra3-b3 6.Rd2xd3 Rb3xd3+ 7.Ke3xd3 a4-a3
-+ (-1.41) Depth: 9 00:00:01 12kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.Rd2xd3 Ra3xd3 7.Ke4xd3 a4-a3
-+ (-1.73) Depth: 9 00:00:01 14kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.Rd2xd3 Ra3xd3 7.Ke4xd3 a4-a3 8.Kd3-c4 Ke6-f6
-+ (-1.73) Depth: 9 00:00:01 15kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.Rd2xd3 Ra3xd3 7.Ke4xd3 a4-a3 8.Kd3-c3 Ke6-f6 9.Kc3-b3
µ (-1.09) Depth: 10 00:00:01 21kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.Rd2-d1 Ra3-b3 7.Rd1xd3 Rb3xd3 8.Ke4xd3 a4-a3 9.Kd3-c3 Ke6-f6 10.Kc3-b3
µ (-1.13) Depth: 10 00:00:01 27kN
1...c4-c3 2.b2xc3 Rb3xc3 3.e3-e4 Rc3xa3 4.Kf3-e3 f5xe4 5.Ke3xe4 Kf6-e6 6.Rd2xd3 Ra3xd3 7.Ke4xd3 a4-a3 8.Kd3-c3 a3-a2 9.Kc3-b2 Ke6-f5 10.Kb2xa2 Kf5xf4
³ (-0.68) Depth: 11 00:00:01 59kN
1...Kf6-e6 2.e3-e4 f5xe4+ 3.Kf3xe4 Rb3-b8 4.Ke4-d4 Rb8-c8 5.Kd4-e4 Ke6-f6 6.h2-h4 h7-h5 7.Rd2-g2 Rc8-e8+ 8.Ke4-d4 Re8-e2 9.Rg2-g1
µ (-1.05) Depth: 11 00:00:01 76kN
1...Kf6-e6 2.e3-e4 f5xe4+ 3.Kf3xe4 Rb3-b8 4.Ke4-d4 Rb8-c8 5.Kd4-e4 Rc8-f8 6.Rd2-d1 Ke6-d6 7.f4-f5 Kd6-c5 8.Rd1-d2 Rf8-e8+ 9.Ke4-f3 Kc5-d5 10.f5-f6 Re8-b8
µ (-0.96) Depth: 12 00:00:01 149kN
1...Rb3-b8 2.h2-h4 Rb8-b3 3.e3-e4 f5xe4+ 4.Kf3xe4 Rb3-b8 5.Rd2-g2 Rb8-e8+ 6.Ke4-d4 Re8-e2 7.Rg2-g1 d3-d2 8.Rg1-d1 Kf6-f5 9.Kd4-c3
µ (-1.21) Depth: 12 00:00:01 218kN
1...Rb3-b7 2.Rd2-g2 Rb7-b8 3.Rg2-d2 Rb8-e8 4.Rd2-d1 h7-h5 5.Rd1-c1 Re8-b8 6.Rc1xc4 Rb8xb2 7.Rc4-c6+ Kf6-e7
µ (-1.25) Depth: 12 00:00:01 256kN
1...Rb3-b7 2.Rd2-g2 Rb7-b8 3.h2-h3 Rb8-b3 4.Rg2-d2 Rb3-b7 5.Rd2-g2 Rb7-g7 6.Rg2xg7 Kf6xg7 7.e3-e4 Kg7-f6 8.Kf3-e3 f5xe4 9.Ke3xe4
µ (-1.29) Depth: 13 00:00:01 323kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.h2-h4 Rb7-e7+ 6.Ke4-d4 Kf6-f5 7.Kd4xc4 Re7-e2 8.Rg2-g1 Kf5-e4 9.Rg1-d1 Re2-c2+ 10.Kc4-b4 Rc2xb2+ 11.Kb4xa4
µ (-1.37) Depth: 14 00:00:01 426kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-c3 Kf6-f5 7.Rg2-f2 Rd7-e7 8.Kc3xc4 Re7-e2 9.Rf2-f1 d3-d2 10.Rf1-d1 Kf5xf4 11.Kc4-d3
µ (-1.25) Depth: 15 00:00:01 598kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-c3 Kf6-f5 7.Rg2-f2 Rd7-e7 8.Kc3xc4 Re7-e2 9.Rf2-f1 d3-d2 10.Rf1-d1 Kf5xf4 11.Kc4-d3
-+ (-1.49) Depth: 15 00:00:02 727kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-c3 Kf6-f5 7.Rg2-f2 Kf5-e4 8.Rf2-f1 Rd7-b7 9.f4-f5 Ke4-d5 10.Rf1-b1 h7-h5
µ (-1.25) Depth: 15 00:00:02 736kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-c3 Kf6-f5 7.Rg2-f2 Kf5-e4 8.Rf2-f1 Rd7-b7 9.f4-f5 Ke4-d5 10.Rf1-b1 Rb7-b3+ 11.Kc3-d2 Kd5-e4
-+ (-1.41) Depth: 16 00:00:02 820kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-c3 Kf6-f5 7.Rg2-f2 Kf5-e4 8.Rf2-f1 Rd7-b7 9.f4-f5 Ke4-d5 10.Rf1-b1 Rb7-b3+ 11.Kc3-d2 Kd5-e4 12.Rb1-e1+ Ke4xf5 13.Re1-f1+ Kf5-e4 14.Rf1-e1+ Ke4-d4
-+ (-1.53) Depth: 16 00:00:02 951kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-e3 Rd7-e7+ 7.Ke3-f3 Re7-e1 8.h2-h4 Kf6-e6 9.h4-h5 Ke6-f6 10.h5-h6 Kf6-f5 11.Rg2-g5+ Kf5-e6 12.Rg5-g2 Ke6-d5 13.Rg2-d2
-+ (-1.65) Depth: 17 00:00:02 1407kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-c3 Kf6-f5 7.Rg2-f2 Kf5-e4 8.Rf2-f1 Rd7-b7 9.f4-f5 Ke4-d5 10.Rf1-b1 Rb7-b3+ 11.Kc3-d2 Kd5-e4 12.Rb1-e1+ Ke4xf5 13.Re1-f1+ Kf5-e4 14.Rf1-e1+ Ke4-d4
-+ (-1.53) Depth: 18 00:00:03 1715kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.e3-e4 f5xe4+ 4.Kf3xe4 Ke6-f6 5.Ke4-d4 Rb7-d7+ 6.Kd4-c3 Kf6-f5 7.Rg2-f2 Kf5-e4 8.Rf2-f1 Rd7-b7 9.f4-f5 Ke4-d5 10.Rf1-b1 Rb7-b3+ 11.Kc3-d2 Kd5-e4 12.Rb1-e1+ Ke4xf5 13.Re1-f1+ Kf5-e4 14.Rf1-e1+ Ke4-d4
-+ (-1.73) Depth: 19 00:00:04 2426kN
1...Rb3-b7 2.Rd2-g2 Kf6-e6 3.h2-h3 Rb7-b3 4.Rg2-d2 Ke6-d5 5.Rd2-g2 c4-c3 6.b2xc3 Rb3xa3
-+ (-1.93) Depth: 19 00:00:04 3137kN
1...Rb3-b7 2.h2-h3 Rb7-g7 3.e3-e4 f5xe4+ 4.Kf3xe4 Rg7-e7+ 5.Ke4-d4 Re7-e2 6.Kd4-c3 Re2-e4 7.Rd2-g2 Re4xf4 8.Rg2-g8 Kf6-e6 9.Rg8-c8 Ke6-d5 10.Rc8-d8+ Kd5-c5 11.Rd8-c8+ Kc5-b5 12.Rc8-b8+ Kb5-c6 13.Rb8-b4 Kc6-d5 14.Rb4xa4
-+ (-1.81) Depth: 19 00:00:04 3947kN
1...Rb3-b7 2.e3-e4 f5xe4+ 3.Kf3xe4 Rb7-e7+ 4.Ke4-d4 Re7-e2 5.Kd4-c3 Re2-e4 6.Rd2-g2 Re4xf4 7.Rg2-g8 Rf4-h4 8.Rg8-c8 Kf6-f5 9.Rc8-c7 Kf5-e6 10.h2-h3 Ke6-d5 11.Rc7-a7 Rh4-h6 12.Ra7xa4
-+ (-1.73) Depth: 20 00:00:05 5536kN
1...Rb3-b7 2.e3-e4 f5xe4+ 3.Kf3xe4 Rb7-e7+ 4.Ke4-d4 Re7-e2 5.Kd4-c3 Re2-e4 6.Rd2-g2 Re4xf4 7.Rg2-g8 Rf4-e4 8.Rg8-f8+ Kf6-g5 9.Rf8-c8 Kg5-f4
-+ (-1.97) Depth: 21 00:00:07 6858kN
1...Rb3-b7 2.h2-h3 Rb7-g7 3.Rd2-d1 Kf6-e6 4.h3-h4 Ke6-d5 5.Rd1-h1 Rg7-g6 6.Rh1-f1 Rg6-b6 7.Rf1-f2 Rb6-h6 8.Rf2-h2 Rh6-g6 9.Rh2-h1 h7-h6 10.Rh1-d1 Rg6-g8 11.Rd1-h1 Rg8-g7 12.h4-h5 Rg7-g8 13.Rh1-d1 Rg8-b8
-+ (-2.06) Depth: 21 00:00:08 7881kN
1...Rb3xb2 2.Rd2xb2 c4-c3 3.Rb2-b6+ Kf6-g7 4.Rb6-b7+ Kg7-h6 5.Rb7-b6+ Kh6-h5 6.Rb6-f6 c3-c2 7.Rf6xf5+ Kh5-h6 8.Rf5-f6+ Kh6-g7 9.Rf6-c6 d3-d2 10.Rc6-c7+ Kg7-h6
-+ (-2.22) Depth: 21 00:00:08 8758kN
1...Rb3xb2 2.Rd2xb2 c4-c3 3.Rb2-b6+ Kf6-g7 4.Rb6-b7+ Kg7-h6 5.Rb7-b6+ Kh6-h5 6.Rb6-f6 c3-c2 7.Rf6xf5+ Kh5-h6 8.Rf5-f6+ Kh6-g7 9.Rf6-c6 d3-d2 10.Rc6-c7+ Kg7-h6
-+ (-2.70) Depth: 21 00:00:09 9390kN
1...Rb3xb2 2.Rd2xb2 c4-c3 3.Rb2-b6+ Kf6-g7 4.Rb6-b7+ Kg7-h6 5.Rb7-b6+ Kh6-h5 6.Rb6-f6 c3-c2 7.Rf6xf5+ Kh5-h6 8.Rf5-f6+ Kh6-g7 9.Rf6-c6 d3-d2 10.Rc6-c7+ Kg7-h6 11.Rc7-c6+ Kh6-h5 12.Rc6-c5+ Kh5-h4 13.Rc5xc2 d2-d1Q+ 14.Rc2-e2 Qd1-d3
-+ (-3.67) Depth: 21 00:00:10 10403kN

(, 18.10.2010)


Gaviota needs 3 plies to see a win. It is done in eval().

Code: Select all

 
         3   1       0.0    -4.94  Rxb2 2.Rxb2
         6   1       0.0    -4.67  Rxa3 2.bxa3
         9   1       0.0    +0.66  h5
        12   1       0.0    +0.71  h6
        24   1       0.0    +1.01  c3 2.bxc3 Rxc3
        35   1:      0.0    +1.01  c3 2.bxc3 Rxc3
        58   2       0.0    +1.01  c3 2.bxc3 Rxc3
       178   2:      0.0    +1.01  c3 2.bxc3 Rxc3
       330   3       0.0    +1.30  c3 2.bxc3 Rxc3 3.Ra2
       483   3       0.0      :-)  Rxb2
       555   3       0.0      :-)  Rxb2
       662   3       0.0    +3.32  Rxb2 2.Rxb2 c3 3.Rb6+ Kf7
       710   3:      0.0    +3.32  Rxb2 2.Rxb2 c3 3.Rb6+ Kf7
      1415   4       0.0    +3.30  Rxb2 2.Rxb2 c3 3.Rb6+ Kf7 4.e4
      1494   4:      0.0    +3.30  Rxb2 2.Rxb2 c3 3.Rb6+ Kf7 4.e4
      2599   5       0.0      :-(  Rxb2
      3406   5       0.0      :-(
      3649   5       0.0      :-(  Rxb2
      4484   5       0.0      :-(
      7280   5       0.1    +3.18  Rxb2 2.Rxb2 c3 3.Rb6+ Kf7 4.Rb7+ Kg6
                                   5.e4
      7328   5:      0.1    +3.18  Rxb2 2.Rxb2 c3 3.Rb6+ Kf7 4.Rb7+ Kg6
                                   5.e4
     17093   6       0.1      :-(  Rxb2
     17241   6       0.1      :-(
     18005   6       0.1      :-(  Rxb2
     20793   6       0.1      :-(
     37744   6       0.2    +3.46  Rxb2 2.Rxb2 c3 3.Rb6+ Kf7 4.Rb5 c2
                                   5.Rxf5+ Ke6 6.Re5+ Kd6
     37804   6:      0.2    +3.46  Rxb2 2.Rxb2 c3 3.Rb6+ Kf7 4.Rb5 c2
                                   5.Rxf5+ Ke6 6.Re5+ Kd6
    104913   7       0.4      :-)  Rxb2
    248023   7       0.9    +4.19  Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6
                                   5.Rb4 c2 6.Rxa4 c1=Q 7.Rd4+ Ke6 8.Rxd3
    249032   7:      0.9    +4.19  Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6
                                   5.Rb4 c2 6.Rxa4 c1=Q 7.Rd4+ Ke6 8.Rxd3
    449321   8       1.6    +4.19  Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6
                                   5.Rb4 c2 6.Rxa4 c1=Q 7.Rd4+ Ke6 8.Rxd3
    452796   8:      1.6    +4.19  Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6
                                   5.Rb4 c2 6.Rxa4 c1=Q 7.Rd4+ Ke6 8.Rxd3
    977254   9       3.4      :-)  Rxb2
   1064345   9       3.7    +4.31  Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6
                                   5.Rxh7 c2 6.Rh6+ Kd5 7.Rh7 c1=Q 8.Rd7+
                                   Ke6 9.Rxd3
   1077397   9:      3.8    +4.31  Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rb7+ Kd6
                                   5.Rxh7 c2 6.Rh6+ Kd5 7.Rh7 c1=Q 8.Rd7+
                                   Ke6 9.Rxd3
   2423659  10       8.3      :-)  Rxb2
   4474021  10      15.2    +5.14  Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rc6 c2
                                   5.Kf2 Kd7 6.Rc4 d2 7.Rxc2 d1=Q 8.Rc5
                                   Qd2+ 9.Kf3
   4513794  10:     15.3    +5.14  Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rc6 c2
                                   5.Kf2 Kd7 6.Rc4 d2 7.Rxc2 d1=Q 8.Rc5
                                   Qd2+ 9.Kf3
   8751065  11      30.0    +5.25  Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rc6 c2
                                   5.Kg3 h6 6.Kf2 Kd7 7.Rc4 d2 8.Rxc2 d1=Q
   8884396  11:     30.4    +5.25  Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rc6 c2
                                   5.Kg3 h6 6.Kf2 Kd7 7.Rc4 d2 8.Rxc2 d1=Q
  22907687  12      79.5    +5.38  Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rc6 c2
                                   5.Kf2 d2 6.Rxc2 d1=Q 7.Rc7+ Kf6 8.Rc6+
                                   Kf7 9.Rc5 Kg6 10.h3
  23346913  12:     81.0    +5.38  Rxb2 2.Rxb2 c3 3.Rb6+ Ke7 4.Rc6 c2
                                   5.Kf2 d2 6.Rxc2 d1=Q 7.Rc7+ Kf6 8.Rc6+
                                   Kf7 9.Rc5 Kg6 10.h3

vladstamate
Posts: 161
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Re: Question regarding WAC number 2

Post by vladstamate » Mon Oct 18, 2010 10:41 pm

May I ask what roughly are you looking for in eval to be able to find that so quickly? I am not interested in duplicating your code of course but maybe you can put me in the general correct direction.

This position has always given Plisk a lot of trouble. It takes 22 plys and 7minutes (at around 300kN/s) to find it. Just blindly increasing the values of passed pawns as well as non-isolani passed pawn does not do it, and in fact it weakens the program overall.

People throw a blanket statement like: 2 connected passed pawns>rook, but how to actually translate that to evaluation code is not really clear to me.

Anyone venture to clarify this a bit?

Regards,
Vlad.

bob
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Location: Birmingham, AL

Re: Question regarding WAC number 2

Post by bob » Tue Oct 19, 2010 12:30 am

vladstamate wrote:May I ask what roughly are you looking for in eval to be able to find that so quickly? I am not interested in duplicating your code of course but maybe you can put me in the general correct direction.

This position has always given Plisk a lot of trouble. It takes 22 plys and 7minutes (at around 300kN/s) to find it. Just blindly increasing the values of passed pawns as well as non-isolani passed pawn does not do it, and in fact it weakens the program overall.

People throw a blanket statement like: 2 connected passed pawns>rook, but how to actually translate that to evaluation code is not really clear to me.

Anyone venture to clarify this a bit?

Regards,
Vlad.
Almost certainly has to be two connected passed pawns on 6th rank. Fine commented that they are worth a rook or more.

It is a dangerous term, however. Move one pawn on this position and the pawns don't win any longer. I used to have a big bonus for 2 connected passers until a long discussion about this position exposed just how tricky this can be if the king can get to the pawns in time...

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michiguel
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Re: Question regarding WAC number 2

Post by michiguel » Tue Oct 19, 2010 1:11 am

vladstamate wrote:May I ask what roughly are you looking for in eval to be able to find that so quickly? I am not interested in duplicating your code of course but maybe you can put me in the general correct direction.
I developed something analogous to a "static exchange evaluator" that is triggered when one side has two pawns in 6 or 7 and the other nothing but a rook. The "moves" allowed in this static evaluator are "rook to the first or a column in which there is one of those pawns", "RxP", KxP", and "king to get closer to the promotion squares", and of course, any advance of those pawns. The "exchange" of moves stops when certain conditions are satisfied. For instance, if the King blocks the pawns, the static search returns "cannot promote" or if "two pawns are in 7th and it is pawn's turn", it returns "can promote".

It took me a long while to be satisfied with it. It was an experiment to see how to introduce dynamic concepts into the evaluation.

Any other simplistic heuristic is doomed to failure here (but I believe that some smart extensions could help).

Miguel

This position has always given Plisk a lot of trouble. It takes 22 plys and 7minutes (at around 300kN/s) to find it. Just blindly increasing the values of passed pawns as well as non-isolani passed pawn does not do it, and in fact it weakens the program overall.

People throw a blanket statement like: 2 connected passed pawns>rook, but how to actually translate that to evaluation code is not really clear to me.

Anyone venture to clarify this a bit?

Regards,
Vlad.

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opraus
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Re: Question regarding WAC number 2

Post by opraus » Tue Oct 19, 2010 1:28 am

OK,

I just removed the connected_passer bonus and xpdnt found the move in 4 seconds. @ 14 ply. So maybe it is the limit on reductions... ?

Also, it still does NOT get wac230 even after 22 ply which takes a couple minutes...
although there have been versions in the past which solved it in under 30sec ... ???

[d]2b5/1r6/2kBp1p1/p2pP1P1/2pP4/1pP3K1/1R3P2/8 b - -

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