The thing about java is that it seems to be a big memory pig. I can't have multiple java processes running without suddenly getting a lot of memory thrashing.
If I do things in C, everything screams. I always figured this is a problem with java that will be solved - but to this day it hasn't happened. I still consider it basically broken, or at least not usable unless you are treating your machine like a single user, single process machine like the old days. I don't have this problem with other high level scripting languages so it cannot be blamed on dynamic memory allocation. It has pretty much turned me off. - Don On Wed, 2006-11-29 at 09:37 -0800, Peter Drake wrote: > On Nov 29, 2006, at 9:26 AM, Eduardo Sabbatella wrote: > > > I'm a full time worker. Before starting my engine (a > > couple of months ago) by 3rd or 4th try. I concluded > > this: > > > > It will be impossible for me to do anything in C, C++ > > because I will have to focus on not having memory > > leaks, range errors, etc. > > > > My engine nowadays is winning agains gnugo on lower > > levels. Without time constrait. Ok, gnugo takes 10 > > secs to play, my engine 90 seconds. > > > > But, something I has sorted out in the beginning: > > > > - I have to optimise algoritms, not code. > > I agree absolutely, and have seen this advice in many books. One went > so far as to propose the two rules of optimization: > > 1. Don't to it. > > 2. (For advanced programmers only) Don't do it yet. > > Algorithmic improvements are much more important than local > efficiency improvements. > > > I think Drake follow the correct path, first optimise > > algorithm on Java, then move it to C/C++. > > Since computer Go algorithms are always, to some degree, in flux, I'm > now leaning toward staying in Java. Yes, C/C++ allows fine control, > but it also requires such fine control that it's hard to think about > larger algorithmic issues. > > > Personally, I found that creating objects in Java is > > realllly expensive. My engine use a lot arrays of > > ints, longs, big linked arrays by reference numbers. > > (yes, a'la C... sometimes I have to resize arrays, its > > costy, but I found that its a lot cheaper on overall > > perfomance than creating objects). > > Yes, in both time and space. I intend to go to some lengths to avoid > dynamic object creation, e.g., creating all of the objects at startup > time and just clearing them out when I need "new" ones. For the most > memory-intensive part of the program (the enormous search tree), I > intend to use a big array of raw ints. Yes, this will be just as ugly > as doing it in C/C++, but at least I'll be able to confine the > ugliness to that part of the program. > > Peter Drake > Assistant Professor of Computer Science > Lewis & Clark College > http://www.lclark.edu/~drake/ > _______________________________________________ > computer-go mailing list > computer-go@computer-go.org > http://www.computer-go.org/mailman/listinfo/computer-go/ _______________________________________________ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
