Author: Bertil Eklund
Date: 13:53:15 05/02/00
Go up one level in this thread
On May 02, 2000 at 08:14:58, Ulrich Tuerke wrote: >On May 02, 2000 at 07:39:03, Bertil Eklund wrote: > >>On May 02, 2000 at 03:48:48, Ulrich Tuerke wrote: >> >>>On May 02, 2000 at 03:41:22, Christophe Theron wrote: >>> >>>>On May 02, 2000 at 03:22:36, Ulrich Tuerke wrote: >>>> >>>>>On May 02, 2000 at 01:10:58, Jouni Uski wrote: >>>>> >>>>>>About one week ago I posted "sensational" blitz Nunn test result Crafty17.10 - >>>>>>Fritz6a 12-8. And I wasn't lying! Now I have more time to re-check and second >>>>>>match ended 9 - 11 for Fritz. I also repeated two other matches with interesting >>>>>>results: >>>>>> 1. 2. >>>>>>Crafty 17.10 - Lg2000 13 - 7 9,5 - 10,5 >>>>>>Fritz6a - Lg2000 13,5 - 6,5 11 - 9 >>>>>> >>>>>>Exact enviroment: AMD 450Mhz, ponder of, 16+16MB hash, 4m+1s level, 3+4+some >>>>>>5 piece TBs, Fritz6 interface, early resign. >>>>>> >>>>>>Conclusion: after 20 games You don't know much yet... >>>>>> >>>>>>Jouni >>>>> >>>>>With learn off, the games should be exactly reproducable (IMHO). Why should the >>>>>search algo of either prog under the same pre-conditions produce another best >>>>>move for any of the positions some time later? >>>>>If you are right, then IMO either (or both) progs are kind of buggy, accessing >>>>>some non-initialized data or similar ? >>>>>Or does any body have anothe explanation ? >>>>> >>>>>Uli >>>> >>>> >>>>The main problem is the way time is measured. >>>> >>>>On the PC, the time functions only return multiples of 1/18.2 seconds. Even >>>>functions that are supposed to return the current time in 1/1000 of s are not >>>>accurate to the millisecond. They are accurate to approximately 5 hundreds of s >>>>(1/18.2=0.054945...). >>>> >>>>So depending exactly when you started a search inside a 1/18.2 seconds time >>>>slice, searching exactly the same number of nodes could fall randomly just >>>>before or just after another given 1/18.2 time slice. >>>> >>>>So when you measure the time taken by a given search, always the same, you end >>>>up with pseudo random results. A search that takes exactly 1 second can be >>>>measured at 0.989s, or at 1.044s, and it depends if it started just before of >>>>just after a clock tick. >>>> >>>>The time allocation algorithm of a program could decide that if a search takes >>>>less than 1 second, it will allow it to complete the next iteration. If it takes >>>>more than one second, it will stop the search immediately and play. >>>> >>>>In the case of our 1 second search, it will sometimes stop the search and play >>>>after 1 second, and sometimes let the search continue for longer. >>>> >>>>There is no way to avoid this problem. Even with a millisecond-accurate timer. >>>>Even if you can measure the time up to the microsecond. >>>> >>>>Random events such as mouse moves, hard disk saving mode and autoplayer random >>>>lags only make this problem worse. >>>> >>>>This is not a bug. You can call this a "quantic" problem. :) >>>> >>>> >>>> >>>> Christophe >>> >>>Thanks, sounds reasonable to me. So, in particular at very short time controls, >>>I would expect that these effects could have some influence in blitz games where >>>the uncertainty is relatively large compared to the time which is needed to >>>search a root move, and Jouni played at rather short controls. I do not think, >>>that these "quantum uncertainties" would be that drastic at tournament controls. >>> >>>Well, if Heisenberg knew ? >>> >>>Uli >>Hi! >> >>I have played a few 1000 games with Comet (most in DOS). There is two programs >>that never seems to repeat a lost or won game and it is Comet and Nimzo. >>I thought it had something to do with the hash-tables. Or do you you use some >>random element to choose moves? Rebel always plays the same if the conditions >>are equal but never Comet or Nimzo. >> >>Bertil Hi! They never repeat wins either. Bertil > >That's not a surprise, because Comet has a positional learning implemented, >using a file on disk. >I think, that I have heard that the same is true for Nimzo. >These are file with the extension .lrn if I remember right. > >Uli
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