Author: Robert Hyatt
Date: 08:03:56 04/02/00
Go up one level in this thread
On April 01, 2000 at 23:17:11, Tina Long wrote: >Hi guys, >This thread has been interesting & generally agreed with previous stuff I'd >read. > >So. >Analysing 3 best moves, over 24hours, slows the program by a factor of 3 - 6, >losing 1 or 2 ply depth. > >Each extra Ply has a 15% of picking a different move, that the software >calculates is better. > >But. >What about the Actual ply depths searched on the 2nd & 3rd preffered moves? >If only the best move is shown, no's 2 & 3 share with no's 4... about 50% of the >search time. > >If best three is shown, no's 2 & 3 are receiving 6 - 10 X more thinking time. >1st preferred move has gone from 50% to 25% of thinking time (25% for "rest") >or 1st preferred move has gone from 50% to 17% of thinking time (50% for "rest") > >preferences 2 & 3 are being searched an extra 1 - 2 - 3 ply deeper over 24hrs. >Their "score" is more acurate than if only 1 best is shown. I don't follow "being searched an extra ply and their score is more accurate than if ..." Here is the main point: If the best move looks best thru 19 plies, but is going to look horrible at depth 20, the 3-best display may ensure that you only get to 19, where you would get to 20 normally. So the normal search will see that the best move is horrible and find an alternative if one is available. The 3-best search will only get to depth 19 and think that the original best move is the one to play. > >So. >If the "score" of the best 3 moves is not too dissimilar, then "forcing" the >program to look at choices 2 & 3 for longer could be a good thing. > >Eg. >guessed ply depths "well" searched for the first four choices over 24 hrs. > >Show 1 best: 1-19 2-15 3-15 4-15 >Show 3 best: 1-17 2-17 3-17 4-13 > >Is the "danger" of reducing the favoured move ply from 19 to 17 greater than the >"benefit" of increasing the 2nd & 3rd ply from 15 to 17? I don't follow how the second/third moves are increased. They are _all_ searched to the same depth each iteration, even in normal mode where only the best move and score is displayed. But _all_ moves are searched to this depth. > >If there is "little to choose" between the best 3 moves, I'd sacrifice the 19 to >17 to pick up the two 15 to 17 searches. (particularly as I intuitively believe >that the benefit of each extra ply reduces - some say by 0%, I guess by 10%) > >Open invitation to shoot my arguments to bits, my appreciation of knowledge on >this exceeds the adamentment of my case. > >Sunday, >Clouds but no rain at >Sunny Mount Kembla > >Tina Long
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