Test position----find the draw

[royb]

How long does it take your program to find the draw?

[D] 2kr3r/1pqbbp2/p2ppn1p/8/3N1P1p/2NBRQ2/PPP3PP/2KR4 w - -

Bright 0.4a finds the draw then thinks that it may not be drawn after all. I'm not sure this is accurate however:

12 -0.52 1.Qh3 Rhg8 2.Be2 h5 3.Nf5 Bc6 4.Nxe7+ Qxe7 5.g3 hxg3 6.hxg3 Ng4 7.Bxg4 hxg4 (24.48)
12 -0.25 1.Bxa6 bxa6 2.Qa8+ Qb8 3.Qxa6+ Qb7 4.Qa5 Rde8 5.Ncb5 Bxb5 6.Rb3 Qa6 7.Rc3+ Kb8 8.Qc7+ Ka8 9.Nxb5 d5 10.a4 (31.48)
13 +0.00 1.Bxa6 bxa6 2.Qa8+ Qb8 3.Qxa6+ Qb7 4.Qa5 Ng4 5.Rf3 Qc7 6.Qa6+ Qb7 7.Qa5 (46.67)
14 +0.00 1.Bxa6 bxa6 2.Qa8+ Qb8 3.Qxa6+ Qb7 4.Qa5 Ng4 5.Rf3 Qc7 6.Qa6+ Qb7 7.Qa5 (72.20)
15 +0.00 1.Bxa6 bxa6 2.Qa8+ Qb8 3.Qxa6+ Qb7 4.Qa5 Qc7 5.Qa8+ Qb8 6.Qa6+ (155.53)
16 +0.53 1.Bxa6 bxa6 2.Qa8+ Qb8 3.Qxa6+ Qb7 4.Qa5 Qc7 5.Qa3 Kb7 6.Ne4 Nd5 7.Rb3+ Nb6 8.Rc3 Qb8 9.Nb3 Ba4 10.Qb4 Rhg8 11.Rd2 (333.99)
17 +0.74 1.Bxa6 bxa6 2.Qa8+ Qb8 3.Qxa6+ Qb7 4.Qa5 Qc7 5.Qa3 Kb7 6.Ne4 Nd5 7.Rb3+ Nb6 8.Rc3 Qb8 9.Nb3 Na4 10.Nxd6+ Bxd6 11.Na5+ Ka8 12.Rxd6 Qa7 (945.20)
18 +0.67 1.Bxa6 bxa6 2.Qa8+ Qb8 3.Qxa6+ Qb7 4.Qa5 Qc7 5.Qa3 Kb7 6.Ne4 Nd5 7.Rb3+ Nb6 8.Rc3 Qb8 9.Nb3 Na4 10.Rcd3 Bb5 11.Qb4 Kc7 12.c4 (1431.61)

System used: Athlon 2.2 GHz 1 CPU

Roy

[royb]

How long does it take your program to find the draw?

[D] 2kr3r/1pqbbp2/p2ppn1p/8/3N1P1p/2NBRQ2/PPP3PP/2KR4 w - -

A second engine that believes there may be more than a draw in this position for White. This is Glaurung 2.2 with some tweaks to make it look deeper for threats:

15 -0.64 1.Kb1 Kb8 2.Rde1 Qb6 3.Nf5 Bf8 4.Nxh4 d5 5.f5 d4 6.fxe6 dxc3 7.b3 Bc5 8.Qf4+ Ka8 9.exd7 Bxe3 10.Rxe3 Rxd7 (40.74)
16 -0.94 1.Kb1 Kb8 2.Nf5 Bc6 3.Qe2 Rhg8 4.Rg1 Ng4 5.Nxe7 Qxe7 6.Rh3 d5 7.Bh7 Rg7 8.Re1 Qb4 9.Qf3 (98.28)
17 -1.03 1.Kb1 Kb8 2.Qe2 Qb6 3.Bc4 d5 4.Bb3 Bc5 5.Red3 Qd6 6.Qf1 Bb4 7.a3 Bxc3 8.Rxc3 Ne4 9.Rh3 Rc8 10.Rxh4 (258.35)
17 +0.00 1.Bxa6 bxa6 2.Qa8+ Qb8 3.Qxa6+ Qb7 4.Qa5 Ng4 5.Rf3 Nxh2 6.Rh3 Qc7 7.Qa8+ Qb8 8.Qa5 Qc7 (442.56)
18 +0.21 1.Bxa6 bxa6 2.Qa8+ Qb8 3.Qxa6+ Qb7 4.Qa5 Ng4 5.Rf3 Nxh2 6.Rh3 Qc7 7.Qa3 Qb7 8.Rxh2 Rdg8 9.Rd2 Rg3 10.Kb1 Rhg8 11.Nf3 Bf6 (514.93)
19 +0.01 1.Bxa6 bxa6 2.Qa8+ Qb8 3.Qxa6+ Qb7 4.Qa5 Ng4 5.Rf3 Nxh2 6.Rh3 e5 7.Nd5 Bxh3 8.Nxe7+ Kd7 9.Ndf5 Bxf5 10.Nxf5 Kc8 11.Nxd6+ Rxd6 12.Rxd6 Ng4 13.fxe5 Qxg2 (629.59)
20 +0.47 1.Bxa6 bxa6 2.Qa8+ Qb8 3.Qxa6+ Qb7 4.Qa5 Ng4 5.Rf3 Nxh2 6.Rh3 e5 7.Nd5 Bxh3 8.Nxe7+ Kd7 9.Ndf5 Bxf5 10.Nxf5 Kc8 11.Nxd6+ Rxd6 12.Rxd6 Re8 13.fxe5 Kb8 14.Rd8+ Rxd8 15.Qxd8+ Ka7 16.Qxh4 Qxg2 17.Qxh6 (1093.01)
21 +0.33 1.Bxa6 bxa6 2.Qa8+ Qb8 3.Qxa6+ Qb7 4.Qa5 Ng4 5.Rf3 Nxh2 6.Rh3 e5 7.Nd5 Bxh3 8.Nxe7+ Kd7 9.Ndf5 Bxf5 10.Nxf5 Kc8 11.Nxd6+ Rxd6 12.Rxd6 Re8 13.fxe5 Ng4 14.Qa4 Rg8 (1542.13)

Roy

[Sven]

Its strange, i agree. Just wasting time printing those repititious moves. The time spent there could've been used searching other possible alternative moves, ....

You are totally wrong about that.

The repitions accumulate because Rybka _is_ "searching other possible alternative moves" but cannot find any, even at deeper depths.

Matthias.

I was only referring to the fact that a PV containing six repetitions is a "past end of game" PV. The game (as it would continue with this PV) would have already ended after the second repetition, so why should an engine continue to search below a terminal position?

EDIT: Or does Rybka 3 store reptition-draw positions in the hash table? That would surprise me but might explain this behaviour.

Sven