OpenChess

Hi all,

I need some help, I hope someone can shed some light on this. I have Arena 3.0, with Houdini 3 Pro x64 and 3, 4 and 5 chessmen tablebases installed and working fine. The engine is configured to use the tablebases and so it does, when I give it a 5 chessmen position and click on ¨analyze¨, it tells the corresponding mate or draw without calculatnig anything. Then I go for something more complex, I give it the following position:
4k3/4pp2/8/8/8/8/4NB2/4K3 w - - 0 1
and click on ¨analyze¨. Within seconds the engine gives an advantage of +6 and the best line shown in the variation board ends with the following position:
8/8/8/2B3N1/4K3/8/6k1/8 w - - 0 1
ot a similar one. Strangely the program doesn't announce mate already.
It continues to work for a long time, even hours, giving better lines
little by little. Shouldn't the program announce mate already? I can't guess what I am doing wrong.

If you install 6 man Nalimov files it would solve it instantly.
You can verify instantly that Kd2 is the best move and wins in 34 here:
http://www.k4it.de/index.php?topic=egtb&lang=en

The real problem is that as long as black can shuffle his chessmen to avoid losing a pawn, there is no way to prove the mate until you have searched 68 plies (and that without pruning). The moves towards the tail of the pv tend to be speculative.

I don't think you are doing anything wrong. If you want to analyze 6 man endgame positions effectively, it would be a good idea to get the full 7TB Nalimov 6 man set.
I understand that ChessOK has completed a 7 man tablebase file set, and there may be some way to access that data online. Probably ChessAssistant and maybe Aquarium will be able to do it? Just speculation.
You could always ask here:
https://plus.google.com/100454521496393505718/posts

As you can see here, with 6 man files hidden, both Rybka and Houdini fare the same on this position:

Analysis of Q:\Kd2.epd
1/25/2013 6:25:55 PM Level: 180 Seconds
Analyzing engine: Houdini_3_AQ_x64 3:t

• 1
  Searching move:
  Best move (Houdini_3_AQ_x64 3:t): Ke1-d2
  Not found in: 03:00
  4/8 00:00 264 12,000 +4.08 Kd2 Kd7 Kd3 e5
  5/10 00:00 596 27,000 +4.06 Kd2 Kd7 Kd3 f5 Nf4 e5
  6/11 00:00 1,139 51,000 +4.06 Kd2 Kd7 Kd3 f5 Kd4 Kd6 Bg3+ Ke6 Nf4+ Kf6
  7/12 00:00 3,863 167,000 +4.01 Kd2 e5 Nc3 Ke7 Kd3 f5 Nd5+ Ke6
  8/15+ 00:00 8,334 347,000 +4.17 Kd2
  8/15 00:00 13,704 548,000 +4.22 Kd2 Kd7 Kd3 f5 Bg3 e6 Bf4 Ke7 Kd4
  9/15 00:00 20,265 723,000 +4.25 Kd2 Kd7 Kd3 f5 Bg3 e6 Kd4 Ke7 Ke5
  10/17 00:00 39,127 1,262,000 +4.26 Kd2 Kd7 Kd3 Kd6 Ke4 e6 Bg3+ Kc5 Be5 Kc4 Nd4
  11/21 00:00 64,451 1,841,000 +4.26 Kd2 Kd7 Kd3 Kd6 Ke4 e6 Bg3+ Kc5 Be5 Kc4 Nd4
  12/21 00:00 146,254 3,111,000 +4.39 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Ke5 Kd7 Nd4 Kc7 Nf5 Kd7 Be3 f6+ Ke4
  13/21 00:00 250,196 3,014,000 +4.40 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Ke5 Kd7 Nd4 Kc7 Nf5 Kd7 Be3 f6+ Ke4
  14/22 00:00 456,896 4,043,000 +4.49 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Nd4+ Kd7 Be1 Kd6 Bb4+ Kd7 Bc5 f6 Kf5 e5 Ne6
  15/27+ 00:00 714,626 4,828,000 +4.67 Kd2
  15/27 00:00 890,904 5,179,000 +4.70 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Ke5 Kd7 Bc5 Ke8 Nd4 Kd7 Kf5 e6+ Kf6 Ke8 Nc6
  16/27+ 00:00 1,208,990 5,702,000 +4.90 Kd2
  16/29 00:00 1,488,471 6,075,000 +4.90 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Ke5 Kd7 Bc5 Ke8 Nd4 Kd7 Kf5 f6 Bb4 e5 Ne2 Kc6 Kxf6 Kd5 Nc3+ Kd4 Kf5
  17/33+ 00:00 2,013,634 6,537,000 +5.10 Kd2
  17/33 00:00 2,408,554 6,823,000 +5.25 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Ke5 Kd7 Bc5 Ke8 Nd4 Kd7 Kf5 f6 Nb3 Kd8 Ke6 Kc7 Bxe7
  18/33+ 00:00 3,074,019 7,199,000 +5.47 Kd2
  18/33 00:00 4,046,278 7,620,000 +5.79 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Nd4+ Kd7 Be1 Kd8 Ke5 Ke8 Bb4 Kd7 Kf5 Kd8 Nc6+ Kc7 Nxe7 Kb6 Ke5 Kb5 Nd5 Kc4 Bd2 Kd3
  19/33 00:00 5,257,391 7,905,000 +5.79 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Nd4+ Kd7 Be1 Kd8 Ke5 Ke8 Bb4 Kd7 Kf5 Kd8 Nc6+ Kc7 Nxe7 Kb6 Ke5 Kb5 Nd5 Kc4 Bd2 Kd3
  20/33 00:00 7,216,184 8,163,000 +5.79 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Nd4+ Kd7 Be1 Kd8 Ke5 Ke8 Bb4 Kd7 Kf5 Kd8 Nc6+ Kc7 Nxe7 Kb6 Ke5 Kb5 Nd5 Kc4 Bd2 Kd3
  21/35 00:01 12,668,242 8,496,000 +5.88 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Nd4+ Kd7 Be1 Kd8 Ke5 Ke8 Bb4 Kd7 Kf5 Kd8 Nc6+ Kc7 Nxe7 Kb6 Kf6 Kb5 Be1 Kc4 Kxf7 Kd3 Ke6 Ke4 Nf5
  22/35 00:02 19,115,034 8,629,000 +5.88 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Nd4+ Kd7 Be1 Kd8 Ke5 Ke8 Bb4 Kd7 Kf5 Kd8 Nc6+ Kc7 Nxe7 Kb6 Kf6 Kb5 Be1 Kc4 Kxf7 Kd3 Ke6 Ke4 Nf5
  23/38 00:04 34,570,805 8,616,000 +5.97 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Nd4+ Kd7 Be1 Kd8 Ke5 Ke8 Bb4 Kd7 Bc5 e6 Kf6 Kc7 Kxf7 e5 Ne6+ Kc6 Kf6 Kd5 Kf5 e4 Be3 Kd6 Nf4 Kc6 Kxe4 Kb7 Kd5 Ka8 Ke5 Kb7 Bf2 Ka8 Ke6
  24/40 00:06 60,200,992 8,690,000 +6.06 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Nd4+ Kd7 Be1 Kd8 Bb4 e6 Ke5 Kc7 Nf3 Kc6 Ng5 Kb5 Be7 f5 Nxe6 Kc6 Kxf5 Kb7 Ke5 Ka8 Kd5 Kb7 Bf6 Ka8 Kc6 Kb8 Bh4
  25/42 00:14 126,112,243 8,762,000 +6.23 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Bh4 Kd6 Nd4 f6 Bg3+ Kc5 Nf5 e6 Nd4 e5 Nf5 Kc6 Bh4 Kc5 Bxf6 Kc6 Bxe5 Kb6 Kd5 Kb7 Nd6+ Kb8 Kc6 Ka8 Kc7 Ka7 Nc8+ Ka8 Nb6+ Ka7 Kc6 Ka6
  26/44 00:29 264,336,225 8,838,000 +6.23 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Bh4 Kd6 Nd4 f6 Bg3+ Kc5 Nf5 e6 Nd4 e5 Nf5 Kc6 Bh4 Kc5 Bxf6 Kc6 Bxe5 Kb7 Kd5 Ka6 Kc6 Ka7 Nd6 Kb8
  27/47 02:56 1,573,944,123 8,940,000 +6.32 Kd2 Kd7 Kd3 Kd6 Ke4 Kc6 Bh4 e6 Nd4+ Kd7 Nf3 e5 Kd5 e4 Ne5+ Kc8 Kxe4 f5+ Kd5 Kb8 Kc6 Kc8 Bf6 Kb8 Nf3 Kc8 Bg5 Kb8 Bf4+ Kc8 Bc7 f4 Bd6 Kd8 Nd4 f3 Nxf3 Kc8 Bf4 Kd8 Nd4 Ke7 Be5 Kd8 Bc7+ Ke7
  1/25/2013 6:28:58 PM, Time for this analysis: 00:03:00, Rated time: 03:00
  
  0 of 1 matching moves
  1/25/2013 6:28:59 PM, Total time: 12:03:03 AM
  Rated time: 03:00 = 180 Seconds
  
  --------------------------------------------------------------------------------
  
  Analysis of Q:\Kd2.epd
  1/25/2013 6:25:55 PM Level: Blitz 5/5
  Analyzing engine: Deep Rybka 4.1 SSE42 x64 {3T}
  
  1
  Searching move:
  Best move (Deep Rybka 4.1 SSE42 x64 {3T}): Bf2-c5
  Not found in: 03:00
  2 00:00 52 331 +4.29 Nc3 Kd7 Ke2
  2 00:00 59 375 +4.34 Nf4 Kd7 Ke2
  3 00:00 125 796 +4.28 Nf4 Kd7 Ke2 Kd6 Nd3 Ke6
  3+ 00:00 185 1,178 +4.46 Kd2 Kd7 Ke3
  3 00:00 227 1,445 +4.43 Kd2 Kd7 Ke3 Ke6 Ke4
  4 00:00 404 2,573 +4.42 Kd2 Kd7 Kd3 e5 Ng3 Ke6 Ke4
  4 00:00 525 3,343 +4.46 Bg3 e6 Nd4 Ke7 Ke2 f6 Ke3
  4 00:00 591 3,764 +4.51 Nd4 Kd7 Bg3 f6 Ke2 e5 Nf5
  5 00:00 1,031 6,566 +4.40 Kd2 Kd7 Kd3 e5 Ng3 Ke6 Ke4 f6
  6+ 00:00 1,720 9,942 +4.52 Kd2 Kd7 Kd3 e5 Ng3 Ke6 Ke4 f6
  6+ 00:00 1,842 10,647 +4.67 Kd2 Kd7 Kd3 e5 Ng3 Ke6 Ke4 f6
  6 00:00 3,113 17,994 +4.73 Kd2 f6 Kd3 e6 Ke4 Ke7 Bc5+ Kf7 Nc3
  7 00:00 7,426 39,291 +4.81 Kd2 e6 Kd3 Ke7 Ke4 f6 Bc5+ Kd7 Nd4 e5
  8 00:00 15,527 70,577 +4.82 Kd2 Kf8 Bc5 Ke8 Kd3 Kd7 Ke4 Ke6 Nf4+
  9 00:00 29,422 117,219 +4.83 Kd2 f6 Kd3 e6 Bc5 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4
  10 00:00 38,614 136,929 +4.83 Kd2 f6 Kd3 e6 Bc5 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4
  11+ 00:00 51,938 165,936 +4.95 Kd2 f6 Kd3 e6 Bc5 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4 Ke8 Kd3 Kf7 Ke4
  11 00:00 59,947 173,759 +4.98 Kd2 f6 Kd3 e6 Bc5 Kd8 Kd4 Ke8 Ke4 Kf7 Nd4 e5 Nf5 Ke6
  12+ 00:00 91,653 216,673 +5.10 Kd2 f6 Kd3 e6 Bc5 Kd8 Kd4 Ke8 Ke4 Kf7 Kd4 e5+ Ke4 Ke6 Ng3 f5+ Nxf5
  12 00:00 100,540 221,453 +5.10 Kd2 f6 Kd3 e6 Bc5 Kd8 Kd4 Ke8 Ke4 Kf7 Nd4 e5 Nf5 Kg6
  13 00:01 263,682 312,419 +5.54 Kd2 Kd7 Ke3 Ke6 Ke4 Kd7 Nd4 e6 Ke5 Ke7 Bh4+ Kd7 Nf3 Ke8 Kf6 Kd7 Ne5+ Kd6 Nxf7+ Kd7
  14 00:01 438,376 350,981 +6.13 Kd2 Kd7 Ke3 Ke6 Ke4 Kd7 Nd4 Kd6 Bg3+ Kd7 Kd5 Ke8 Bh4 Kd7 Ke5 f6+ Kd5 e6+ Nxe6 Ke7 Nd4 Kf7 Nf5 Kg6 Ke6 Kh5 Bxf6
  15 00:02 612,201 373,521 +6.23 Kd2 Kd7 Ke3 Ke6 Ke4 Kd7 Ke3 Ke6 Ke4 Kd7 Ke3 Ke6 Ke4 Kd7 Ke3 Ke6 Ke4 Kd7 Ke3 Ke6 Ke4 Kd7 Ke3 Ke6 Ke4 Kd7 Ke3 Ke6 Ke4 Kd7 Ke3
  16 00:02 845,299 395,184 +6.23 Kd2 Kd7 Ke3 Ke6 Ke4 Kd7 Ke3 Ke6 Ke4 Kd7 Ke3 Ke6 Ke4 Kd7 Ke3 Ke6 Ke4 Kd7 Ke3 Ke6 Ke4 Kd7 Ke3 Ke6 Ke4 Kd7 Ke3 Ke6 Ke4 Kd7 Ke3
  17 00:03 1,366,729 421,050 +6.44 Kd2 Kd7 Ke3 Ke6 Ke4 Kd7 Bg3 Kd8 Bh4 Ke8 Ke5 Kd8 Nd4 Kd7 Ke4 e6 Ke5 Kc7 Nf3 Kd7 Bf2 Kd8 Ng5 Ke7 Bc5+ Ke8 Bd6 Kd7 Nxf7 Kc6 Ng5
  18 00:05 2,043,601 443,971 +6.57 Kd2 Kd7 Ke3 Ke6 Ke4 Kd7 Ke5 Kd8 Bh4 Ke8 Nd4 Kd7 Ke4 Ke8 Kd5 Kf8 Ke5 Kg7 Bxe7 Kg6 Nf5 Kh5 Nd6 Kg6 Bf6
  19 00:06 2,955,682 462,041 +6.57 Kd2 Kd7 Ke3 Ke6 Ke4 Kd7 Ke5 Kd8 Bh4 Ke8 Nd4 Kd7 Ke4 Ke8 Kd5 Kf8 Ke5 Kg7 Bxe7 Kg6 Bf6 Kh5 Nf5 Kg4 Nh6+ Kf3 Nxf7
  20 00:10 4,621,940 485,650 +6.58 Kd2 Kd7 Ke3 Ke6 Ke4 Kd7 Nd4 Kd6 Bg3+ Kd7 Bh4 Ke8 Kf5 Kf8 Nc6 Ke8 Nxe7 Kd8 Kf6 Kc7 Bf2 Kd6 Bd4 Kd7 Kxf7 Kd6 Nf5+
  21 00:15 7,540,792 495,745 +6.59 Kd2 Kd7 Ke3 Ke6 Bh4 Kd6 Ke4 Kd7 Nd4 Ke8 Kf5 Kd7 Ke5 e6 Nf3 Ke8 Kf6 Kd7 Ne5+ Kd6 Nxf7+ Kc5 Kxe6 Kd4 Bf6+ Ke4 Bg5 Kd4 Bf6+ Ke4 Bg5
  22 00:21 10,771,489 513,710 +6.59 Kd2 Kd7 Ke3 Ke6 Bh4 Kd6 Ke4 Kd7 Nd4 Ke8 Kf5 Kd7 Ke5 e6 Nf3 Ke8 Kf6 Kd7 Ne5+ Kd6 Nxf7+ Kc5 Kxe6 Kd4 Bf6+ Ke4 Bg5 Kd4 Bf6+ Ke4 Bg5
  23 00:33 17,676,127 530,193 +6.76 Kd2 Kd7 Ke3 Ke6 Bh4 Kd6 Ke4 Kd7 Nd4 Ke8 Kf5 Kd7 Ke5 e6 Nf3 Ke8 Kf6 Kd7 Ne5+ Kd6 Nxf7+ Kc5 Kxe6 Kd4 Bf6+ Ke4 Nd6+ Ke3 Kd5 Kf3 Bb2
  24 00:57 31,084,856 547,702 +6.88 Kd2 Kd7 Ke3 Ke6 Bh4 Kd6 Ng3 f6 Ke4 Kc6 Ne2 Kc5 Bf2+ Kd6 Kf5 Kd5 Nf4+ Kd6 Ne6 Kd7 Bd4 Kc8 Bc5 Kd7 Nf4 e5 Ne2 Kc6 Be7 Kb6 Bxf6
  25 01:42 57,257,573 558,899 +6.94 Kd2 Kd7 Ke3 Ke6 Ke4 Kd6 Be1 e6 Bb4+ Kd7 Ke5 Kc6 Nd4+ Kc7 Be7 Kd7 Kf6 e5 Nf5 Kc6 Kxe5 Kb5 Kd5 Ka5 Nd4 Kb6 Ke5 Kc7 Kf6 Kd7 Kxf7
  26 02:11 74,287,200 568,588 +6.94 Kd2 Kd7 Ke3 Ke6 Ke4 Kd6 Be1 e6 Bb4+ Kd7 Ke5 Kc6 Nd4+ Kc7 Be7 Kd7 Kf6 e5 Nf5 Kc6 Kxe5 Kb5 Kd5 Ka5 Nd6 Ka4 Nxf7 Kb3 Bf6 Kc2 Bd4
  26 02:54 99,944,864 573,607 +7.00 Bc5 Kd7 Kf2 e6 Ke3 Kc6 Kd4 Kd7 Nc3 Kc6 Be7 Kd7 Bb4 Kc6 Ba3 f6 Be7 f5 Ke5 Kd7 Bf6 Kc6 Kxe6 Kc5 Kxf5 Kb4 Ke4 Kc5 Nd5 Kc4 Be5
  1/25/2013 6:38:19 PM, Time for this analysis: 00:03:00, Rated time: 03:00
  
  0 of 1 matching moves
  1/25/2013 6:38:20 PM, Total time: 12:12:24 AM
  Rated time: 03:00 = 180 Seconds

Well, my point is that as soon as the analysis changes from a 6 pieces position to a five pieces position the engine should check and see the result without more calculation needed to announce mate, which it doesn't. Of course more calculation may be needed to give a shorter or shortest mate but the mate should be announced already.