Author: Andrew Dados
Date: 13:07:54 07/12/02
Go up one level in this thread
On July 12, 2002 at 14:56:11, Ed Schröder wrote: >Hi CCC, > >In Rebel I maintain a statistic file, on every iteration a counter is >incremented with 1 (see column 2) representing the iteration depths Rebel has >searched. When a new best move is found a second counter is incremented with 1 >(see column 3) representing how many times a new best move has been found on the >given iteration depth, between brackets the percentage is calculated. > >As you can see the very first plies Rebel often changes to new best moves, >however when the depth increases and increases the chance Rebel will change its >mind drops and drops. From 16 plies on the chance a new better move is found is >below 2%. > >I wonder what this all means, it is still said (and believed by many) that a >doubling in computer speed gives 30-50-70 elo. That could be very well true for >lower depths but the below statistic seem to imply something totally different, >a sharp diminishing return on deeper depths. > >Interesting also is colum 4 (Big Score Changes), whenever a big score difference >is measured (0.50 up or down) the percentage is calculated. This item seems to >be less sensitive than the change in best move. However the maintained "Big >Score Changes" statistic is not fully reliable as it also counts situations like >being a rook or queen up (or down) in positions and naturally you get (too) many >big score fluctuations. I have changed that and have limit the system to scores >in the range of -2.50 / +2.50 but for the moment have too few games played to >show the new statistic. > >Anyway the number of positions calculated seem to be more than sufficient (over >100,000) to be reliable. The origin came from extensive testing the latest Rebel >via self-play at various time controls. > > > SEARCH OVERVIEW > =============== > >Depth Moves Moves Big Score > Searched Changed Changes > > 1 113768 0 = 0.0% 0 = 0.0% > 2 113768 44241 = 38.9% 25329 = 22.3% > 3 113768 34262 = 30.1% 10707 = 9.4% > 4 113194 32619 = 28.8% 6939 = 6.1% > 5 113191 30697 = 27.1% 6353 = 5.6% > 6 108633 28516 = 26.2% 4954 = 4.6% > 7 108180 25437 = 23.5% 3952 = 3.7% > 8 102782 22417 = 21.8% 3265 = 3.2% > 9 82629 15400 = 18.6% 2541 = 3.1% >10 59032 9144 = 15.5% 1866 = 3.2% >11 39340 5183 = 13.2% 1384 = 3.5% >12 23496 2350 = 10.0% 982 = 4.2% >13 12692 957 = 7.5% 522 = 4.1% >14 6911 396 = 5.7% 369 = 5.3% >15 4032 193 = 4.8% 179 = 4.4% >16 2471 72 = 2.9% 127 = 5.1% >17 1608 26 = 1.6% 58 = 3.6% >18 1138 17 = 1.5% 42 = 3.7% >19 921 6 = 0.7% 26 = 2.8% >20 795 7 = 0.9% 22 = 2.8% >21 711 1 = 0.1% 18 = 2.5% >22 636 2 = 0.3% 10 = 1.6% >23 574 5 = 0.9% 10 = 1.7% >24 507 1 = 0.2% 12 = 2.4% >25 451 3 = 0.7% 7 = 1.6% >26 394 1 = 0.3% 10 = 2.5% >27 343 2 = 0.6% 3 = 0.9% >28 296 2 = 0.7% 7 = 2.4% >29 269 0 = 0.0% 7 = 2.6% >30 240 0 = 0.0% 6 = 2.5% >31 217 0 = 0.0% 6 = 2.8% >32 208 0 = 0.0% 7 = 3.4% >33 187 0 = 0.0% 3 = 1.6% >34 169 0 = 0.0% 1 = 0.6% >35 159 0 = 0.0% 1 = 0.6% >36 144 0 = 0.0% 0 = 0.0% >37 138 0 = 0.0% 0 = 0.0% >38 134 0 = 0.0% 0 = 0.0% >39 125 0 = 0.0% 0 = 0.0% >40 117 0 = 0.0% 0 = 0.0% >41 105 0 = 0.0% 0 = 0.0% >42 97 0 = 0.0% 0 = 0.0% >43 83 0 = 0.0% 0 = 0.0% >44 73 0 = 0.0% 0 = 0.0% >45 67 0 = 0.0% 0 = 0.0% >46 62 0 = 0.0% 0 = 0.0% >47 55 0 = 0.0% 0 = 0.0% >48 51 0 = 0.0% 0 = 0.0% >49 49 0 = 0.0% 0 = 0.0% >50 47 0 = 0.0% 0 = 0.0% >51 46 0 = 0.0% 0 = 0.0% >52 46 0 = 0.0% 0 = 0.0% >53 44 0 = 0.0% 0 = 0.0% >54 43 0 = 0.0% 0 = 0.0% >55 43 0 = 0.0% 0 = 0.0% >56 42 0 = 0.0% 0 = 0.0% >57 41 0 = 0.0% 0 = 0.0% >58 40 0 = 0.0% 0 = 0.0% >59 40 0 = 0.0% 0 = 0.0% >60 38 0 = 0.0% 0 = 0.0% Thanks for that data. There are few things that come to mind here... First is endgame vs middlegame data - I believe since BF is drastically different those 2 stages will produce different curves. Then there is this effect of searching MUCH deeper when there is an easy move: recapture or check evasion or simple forced move. Those moves will get 2+ plies deeper in search and affect your statistic greatly: best move won't change. (unless you auto-played with some easy-move algorithm and terminated search sooner) On the other hand in really complicated positions with big BF you are getting to smaller depths. And those positions are really interesting. I believe chess game consist of mostly 'easy' moves. That 2-3 'hard' moves in a game make all the difference though. -Andrew-
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