Author: Ed Schröder
Date: 14:52:26 07/16/00
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On July 16, 2000 at 06:34:46, blass uri wrote: >On July 16, 2000 at 03:34:45, Ed Schröder wrote: > >>>posted by Dann Corbit on July 15, 2000 at 20:21:54: >> >>>Simplifying. I have a penny. >>>I toss it twice. >>>Heads, heads. >>>I toss it twice >>>Heads, heads. >>>I toss it twice >>>Tails, heads. >>>I toss it twice >>>Heads, tails. >> >>>I count them up. >> >>>Heads are stronger than tails. >> >>>My conclusion is faulty. Why? Because I did not gather enough data. >> >>Right. >> >>A few months ago Christophe posted some interesting stuff here regarding >>this topic and nobody really was in agreement with him (me included) until >>I did an experiment which worked as an eye opener for me. The story is not >>funny and goes like this... >> >>In Rebel Century's Personalities you have the option [Strength of Play=100] >>The value may vary from 1 to 100 and 100 is (of course) the default value. >> >>Lowering this value will cause Rebel to lower its NPS. This opens the >>possibility to create (100% equal!) engines with as only difference >>they run SLOWER. >> >>I was interested to know HOW MANY games it was needed to show that a 10% >>faster version could beat a 10% slower version and with which numbers. So >>I created two personalities: >> >>FAST.ENG (default settings) [Strength of Play=100] >>SLOW.ENG (default settings) [Strength of Play=80] >> >>and started to play 600 eng-eng games with Rebel's build-in autoplayer >>with pre-defined fixed opening lines both engines had to play with white >>and black. >> >>The personality with as only change [Strength of Play=80] caused Rebel to >>slow down with exactly 10% on the machine the marathon match took place. >>Note that this value (80) may differ on other PC's in case you want to do >>similar experiments. >> >>Here are the results of the 600 games played between the FAST and SLOW >>personalities. The first 300 games were played on a time control of "5 >>seconds average". The second 300 games were played on a time control of >>"10 seconds average". >> >>FAST - SLOW 162.5 - 137.5 [ 0:05 ] >>FAST - SLOW 147.0 - 153.0 [ 0:10 ] >> >>The first match of 300 games at 5-secs looks convincing. A 54.1% score >>because of the 10% more speed seems a value one might expect. > >I think that there may be a factor of luck in the choice of the opening. >I think that in order to avoid this problem you can play 150 games with white >and after it play 150 games with black with reversed colours. >I think that in this case the chances of the slow version to win are smaller. No luck is involved. Both engines play pre-defined (not too short) opening lines and with reversed colors. Ed >I think that 10% faster is about 8 elo better. >8 elo better suggests a result of 153-147 and simple statisics tells me >that the standard deviation is about 7 points(I am not sure about the >probability f wins and draws so the exact standard devation is not clear). > >It means that in 95% of the cases you will get something between 161-139 for the >weaker player and 167-133 for the stronger player so both results are logical >and not surprising. > >I believe that playing in reversed colours after half of the game reduce the >standard deviation but I still think that 300 games are not significant even in >this case. > >Uri
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