Author: Uri Blass
Date: 05:15:02 07/13/02
Go up one level in this thread
On July 13, 2002 at 07:09:02, José Carlos wrote: >On July 13, 2002 at 05:35:24, Uri Blass wrote: > >>On July 12, 2002 at 19:16:31, José Carlos wrote: >> >>>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. >>> >>> Hi Ed, if I get this right, the second column (moves searched) is the number >>>of positions in which the program has reached the depth given by column 1. If it >>>was really "moves", there would be about 3x in depth 2 than in depth 1. >>> Then the idea is that many more changes happen in low depths because the >>>program is there many more times, so I (ignoring "Big Changes") calculated a >>>couple of other numbers: >>> The ratio moves changes / moves searched and the relative % of changes from >>>ply to ply: >>> >>> SEARCH OVERVIEW >>> =============== >>> >>> (A) (B) (C) (D) (E) >>>Depth Moves Moves Moves Changed / rel % of changes from >>> Searched Changed Moves Searched ply n-1 to n >>> >>> 1 113768 0 = 0.0% 0 >>> 2 113768 44241 = 38.9% 0.388870333 >>> 3 113768 34262 = 30.1% 0.30115674 77.44% >>> 4 113194 32619 = 28.8% 0.288168984 95.69% >>> 5 113191 30697 = 27.1% 0.271196473 94.11% >>> 6 108633 28516 = 26.2% 0.262498504 96.79% >>> 7 108180 25437 = 23.5% 0.235135885 89.58% >>> 8 102782 22417 = 21.8% 0.218102391 92.76% >>> 9 82629 15400 = 18.6% 0.186375244 85.45% >>>10 59032 9144 = 15.5% 0.154899038 83.11% >>>11 39340 5183 = 13.2% 0.131748856 85.05% >>>12 23496 2350 = 10.0% 0.100017024 75.91% >>>13 12692 957 = 7.5% 0.075401828 75.39% >>>14 6911 396 = 5.7% 0.057299957 75.99% >>>15 4032 193 = 4.8% 0.047867063 83.54% >>>16 2471 72 = 2.9% 0.029138001 60.87% >>>17 1608 26 = 1.6% 0.016169154 55.49% >>>18 1138 17 = 1.5% 0.014938489 92.39% >>>19 921 6 = 0.7% 0.006514658 43.61% >>>20 795 7 = 0.9% 0.008805031 135.16% >>>21 711 1 = 0.1% 0.00140647 15.97% >>>22 636 2 = 0.3% 0.003144654 223.58% >>>23 574 5 = 0.9% 0.008710801 277.00% >>>24 507 1 = 0.2% 0.001972387 22.64% >>>25 451 3 = 0.7% 0.006651885 337.25% >>>26 394 1 = 0.3% 0.002538071 38.16% >>>27 343 2 = 0.6% 0.005830904 229.74% >>>28 296 2 = 0.7% 0.006756757 115.88% >>>29 269 0 = 0.0% 0 0.00% >>> >>> Column (D) means the probability at a certain position at a certain depth to >>>get a change, according to your data, for a random position (I assume you chose >>>random positions, because this data comes from real games). >> >>No >> >>I assume that the positions that was searched to big depthes like 16 are only >>positions that the program had enough time to search in the game to depth 16. >> >>These positions are not random positions from games. >>I expect in random positions from games to see at least 10% changes at depth 16. >> >>Uri > > It's interesting that Ed, who has been doing chess programming for a lot of >years rely on statistical data, and you, absolute newbie to chess programming >can 'expect'. Quite amazing. > > José C. I do not find it amazing. I have experience in correspondence games when I let programs to analyze for a lot of hours. The case when they change their mind to a new move after many hours is not rare and certainly happen in more than 2% and they get depthes that are bigger than 16 after many hours. My estimate of 10-15% is based on my experience in correspondence games and reading material about the subject. I did not calculate statistics about deep searches for my correspondence games but I remember that I read researches when 13-14% at big depth was mentioned(I think it was about crafty goes deep and dark though go deep). Uri
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