Author: Robert Hyatt
Date: 09:37:02 09/11/02
Go up one level in this thread
On September 11, 2002 at 08:09:52, Steffen Basting wrote: >Hello! >I've got some problems with my hashtable... >Here's the output of the starting position: Several questions come to mind, but your PV brings up an important one first: When you get an EXACT hash match, do you _build_ a PV at that point just like you should be doing in Quiesce()??? If you don't you will have garbage lying around in the PV since nothing is getting put in it, and you are about to return with an EXACT score and back up whatever is there. Take the PV construction code from quiesce() and copy it into the search code at the point where you realize you get an EXACT match, so that you will get a good PV to back up with that score. Those illegal moves simply should _never_ show up in a real PV and being there indicates a fundamental error in the PV code. Fix that _before_ trying to fix the hash code... > >time depth nodes value principal variation >=============================================================================== >0 1 24 -10 g1f3 >0 2 66 -11 g1f3 - >0 2 130 -28 g1f3 g8f6 >0 3 134 -27 g1f3 + >0 3 719 -4 g1f3 g8f6 b1c3 >0 4 722 -3 g1f3 + >0 4 895 -5 g1f3 - >0 4 4027 -22 g1f3 g8f6 b1c3 b8c6 >0 5 6229 -21 g1f3 + >0 5 18882 -7 g1f3 g8f6 b1c3 b8c6 e2e4 >1 6 22129 -8 g1f3 - >1 6 85215 -21 d2d4 g8f6 g1f3 d7d5 b1c3 b8c6 >2 7 198553 -20 d2d4 + >3 7 518883 -7 e2e4 b8c6 g1f3 g8f6 b1c3 d7d5 f1d3 >8 8 600111 -8 e2e4 - >9 8 4135936 -14 g1f3 g8f6 b1c3 b8c6 d2d4 e7e6 c1g5 d7d5 >56 9 7292704 -13 g1f3 + >705603 nodes, 101 seconds: 71497 nodes/sec >q-nodes: 6587101 evals: 6587101 >hash hits: 168 hash alpha cut: 106 hash beta cut: 0 >value: -13 >my move: g1f3 > >And another one from the following position: >[D]8/5ppp/8/5PPP/8/k7/8/K7 w - - 0 1 > >time depth nodes value principal variation >=============================================================================== >1 9 57531 20 a1b1 - >1 9 107320 19 a1b1 a3b4 h5h6 g7h6 g5h6 f7f6 b1c1 b4b3 >c1b1 >2 10 132473 20 a1b1 + >2 10 225075 24 a1b1 a3b4 b1c2 b4c5 h5h6 g7h6 g5h6 f7f6 >c2c1 c5c4 >2 11 258326 25 a1b1 + >3 11 531269 688 g5g6 h7g6 f5f6 g7f6 h5h6 f6f5 h6h7 f5f4 >h7h8Q f7f5 a1b1 >5 12 569305 687 g5g6 - >5 12 2047277 689 a1b2 a3b2 b2a3 a3a2 a2a3 b2a1 a1a2 a2b2 >b2a2 b3b2 b1b2 b2b1 b1b2 + >16 12 2898223 695 g5g6 h7g6 f5f6 g7f6 h5h6 f6f5 h6h7 f5f4 >h7h8Q f7f6 h8a8 a3b4 b1b2 >22 13 3236424 696 g5g6 + >25 13 3988875 698 g5g6 h7g6 f5f6 g7f6 h5h6 f6f5 h6h7 a3b4 >h7h8Q f7f6 h8g8 g6g5 g8e8 >1138587 nodes, 31 seconds: 124652 nodes/sec >q-nodes: 2850288 evals: 2850288 >hash hits: 424 hash alpha cut: 318 hash beta cut: 0 >value: 698 >my move: g5g6 > >Something is wrong - I simply don't find the mistake...Have a look at the line >of depth 12 for example - if the search had stopped at this point, my program >would had lost in a won position with a positive score. >Any suggestions - what might be the mistake? > >Thanks, Steffen
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