Author: Dan Homan
Date: 06:08:49 01/13/98
Go up one level in this thread
On January 12, 1998 at 14:49:17, Robert Hyatt wrote: >On January 12, 1998 at 14:23:02, Dan Homan wrote: > >>Test Position: WAC 003 >> >> +---+---+---+---+---+---+---+---+ >>8 | | | | | | *R| *K| | White to move >> +---+---+---+---+---+---+---+---+ >>7 | | *P| *P| *B| | | | *P| castle: - >> +---+---+---+---+---+---+---+---+ >>6 | *P| | *P| *B| | | | | >> +---+---+---+---+---+---+---+---+ >>5 | | | | | | | *Q| | >> +---+---+---+---+---+---+---+---+ >>4 | | | | P | | *P| | *R| fifty: 0 >> +---+---+---+---+---+---+---+---+ >>3 | | | P | | R | | | P | >> +---+---+---+---+---+---+---+---+ >>2 | P | P | | B | Q | | P | | >> +---+---+---+---+---+---+---+---+ >>1 | | | | | | R | K | N | >> +---+---+---+---+---+---+---+---+ >> a b c d e f g h >> >> >>White to Move Book Move: Rg3; >> >>Press 's' to search, 'n' for the next position, 'q' to exit: s >>Please enter a search time (in seconds): 30 >> 3. 154 0 1300 e3g3 g5g3 h1g3 >> 4. 313 0 5297 e3g3 d7g4 g3g4 >> 5. 313 0 10408 e3g3 d7g4 g3g4 >> 6. 313 2 53982 e3g3 d7g4 g3g4 >> 7. 313 5 174534 e3g3 d7g4 g3g4 >> 8. 313 20 735301 e3g3 d7g4 g3g4 h4g4 e2e6 g8h8 >> h3g4 g5f6 f1e1 f4f3 >> >>node_count = 885911 quiescent nodes = 82048 eval_count = 183571 >>hash hits = 74864 hash moves = 9095 pawn hash hits = 173696 >>node_rate = 36912 null cutoffs = 167276 extensions = 15099 >> > >I tried this to a depth of 8 plies (which I assume the above means >you reached?) Total time was 2 seconds, with a hash hit rate of 99%. >I re-ran it to 30 seconds and was able to search 11 plies deep this >time, and the pawn hash hit rate was still 99%. I used 5mb for the >pawn hash, where one entry is 20 bytes. > I was just looking at these numbers and noticed that you are reaching depth 8 in just 2 seconds! It takes me 20 to reach depth 8 (time to complete the first PV on depth 8, the rest of the moves at depth 8 take still more time). This is a factor of 10! Even assmuning a generous factor of 3 in nps advantage, crafty is searching about a factor of 3 fewer nodes! I can think of a few reasons that my search would have more nodes, but none of them should be a factor of 3. One thing that did occur to me is extensions. I turned off all extensions and researched this position. In doing so, I found that I searched only about 30% of the nodes to reach the same depth as the above example. Should my extensions really be tripling the size of my search tree? I like the extensions a lot, just adding them in has increased my program's blitz rating on FICS by 200 points (now about 2030). I am wondering, however, if I have overdone it. What do you typically expect the increase in tree size to be with reasonable extensions? - Dan p.s. My program does capture extensions (4/10 of a ply) re-capture extensions (1 ply) check extensions (1 ply) pawn push extensions (1/2 ply or 1/3 ply) (endgame and late middle-game) bruce's mate ext. (1 ply)
This page took 0.01 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.