Author: Miguel A. Ballicora
Date: 12:48:36 01/01/03
Go up one level in this thread
On January 01, 2003 at 15:47:07, Miguel A. Ballicora wrote: >On January 01, 2003 at 01:01:24, Robert Hyatt wrote: > >>On December 31, 2002 at 20:32:28, Uri Blass wrote: >> >>>On December 31, 2002 at 19:50:43, Robert Hyatt wrote: >>> >>>>On December 31, 2002 at 17:49:52, Uri Blass wrote: >>>> >>>>>From Ed programmer stuff >>>>> >>>>>Killer-One [current ply] 110 >>>>>Killer-One [current ply-2] 108 >>>>>Killer-Two [current ply] 106 >>>>>Killer-Two [current ply-2] 104 >>>>> >>>>>I until today used only >>>>> >>>>>Killer-One [current ply] >>>>>Killer-Two [current ply] >>>>> >>>>>I am interested to know if using 4 killers is a new idea or maybe this idea is >>>>>known to be used by other programs. >>>> >>>>It was known in 1975. Chess 4.0 used this. You can find it mentioned in >>>>the chess 4.7 chapter of "Chess Skill in Man and Machine." >>>> >>>>We did that in Cray Blitz, but we also did more killers, going back to the >>>>root in fact... >>>> >>>> >>>> >>>>> >>>>>I did try part of the idea that Ed suggested without clear results. >>>>> >>>>>I changed the order of moves in movei to >>>>> >>>>>Killer-One [current ply] >>>>>Killer-One [current ply-2] >>>>>Killer-Two [current ply] >>>>> >>>>>instead of >>>>> >>>>>Killer-One [current ply] >>>>>Killer-Two [current ply] >>>>> >>>>>I found that it is better only in part of the cases and have not clear results >>>>>if it is better or worse than previous order but I had a bug in the >>>>>implementation and I checked killer[ply-2] even in cases when ply-2<0. >>>>> >>>>>It is surprising that the program did not crush and even performed better in >>>>>part of the cases. >>>>> >>>>>I still do not use check bound software. >>>>>I asked in a previous discussion about checking bounds but I solved the >>>>>problem that caused me to ask about it and I also read a claim that if a >>>>>varaible is out of bound the program should crush. >>>>> >>>>>I also looked for a software that will help me under visual C++ but after I >>>>>asked to get it for free evaluation and I only got an email that suggest me to >>>>>contact them by fax or telephone I did not respond(I responded by email but my >>>>>email was blocked for some reason and I decided that the subject is probably not >>>>>very important). >>>>> >>>>>I think now that it may be important because a chess program may even play well >>>>>inspite of the fact that it calls killer[-1] so it is possible that I have more >>>>>mistakes like that. >>>>> >>>> >>>>That probably won't hurt a thing. That move probably would not pass your >>>>legality check, so even a garbage move would just waste a tiny bit of time >>>>as you notice it is not legal in the current position. >>> >>>Yes but I can still imagine problems. >>> >>>1)If I am unlucky a garbage move may be legal so it can be counterproductive. >>> >>>2)I thought that garbage may do something worse than giving a random >>>number. >>>I thought that if my program try to look at some place that does not exist the >>>program may crush and not give me a random number or may change another array. >>> >>>I also cared not to have -1 >>> A[x]=1; and not >>>if (x>=0) >>>A[x]=1; >> >>That doesn't hurt a thing. a[-1] is one "thing" before a[0]. If a is an >>integer, a[-1] is simply 4 bytes in front of a[0]... > >It might not hurt, but it is undefined behavior. The computer could easily >crash. I would not recommend it. > >int a[10]; > >mean that it is valid to access the value from a[0] to a[9] and use the >addresses from a[0] to a[10]. Anything else is dangerous. "and use the addresses from &a[0] to &a[10]..." Miguel > >Miguel
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