Author: Eugene Nalimov
Date: 20:14:45 04/16/01
Go up one level in this thread
On April 16, 2001 at 23:06:55, Robert Hyatt wrote: >On April 16, 2001 at 22:53:34, Eugene Nalimov wrote: > >>On April 16, 2001 at 22:07:10, Robert Hyatt wrote: >> >>>On April 16, 2001 at 18:15:52, Dieter Buerssner wrote: >>> >>>>In a different discussion, Vincent wrote the following: >>>> >>>>>It is not difficult to implement the form of parallellism as used by >>>>>Rudolf. Invented by a frenchman who couldn't spell a word english and >>>>>who wrote an impossible article for JICCA (did anyone proofread it at >>>>>the time as i'm pretty sure they didn't get his parallel idea?). >>>>> >>>>>At the time when i read the article i was pathetically laughing about it >>>>>actually as i also didn't get the idea of the frenchman. But it appears >>>>>everyone who can make a chessprogram work under win2000 can also get >>>>>within an afternoon his program parallel to work. Then some debugging >>>>>and a day later it works cool. >>>> >>>>I'd be very interested in this algorithm, that can be implemented at an >>>>afternoon :-) >>>> >>>>Could you point elaborate on this. >>>> >>>>BTW. In Paderborn, Roland Pfister also told me, that he knows this from Rudolf >>>>Huber, and he even started to explain it to me. Somhow, we (or me) got >>>>distracted, and I cannot remember the essential things. >>>> >>>>What I remember is, that the time consuming work, of making your >>>>search/evaluation routines free from all those global variables is not needed. >>>> >>>>Regards, >>>>Dieter >>> >>> >>>Global variables will _always_ be a problem. Unless you avoid threads >>>altogether and use separate processes. But then you incur other penalties >>>you have to solve... >> >>Visual C allows you to declare the global variable as "thread-specific", i.e. >>each thread will have its own copy of the variable. Compiler generates special >>code to access such a variables. >> >>Eugene > > >Many machines have a variant of this. On the Cray, we had global variables >in FORTRAN via a "common" statement. They added "task common" which were >global but thread-specific. > >I do the same thing via pointers in normal C. A thread-specific (local) pointer >that points to a global area that is allocated to a specific thread for its >exclusive use... > >But any such thing causes syntacical changes and lots of debugging... My point was that it's not necessary to introduce a lot of syntax changes. I belive that changing several declarations is not a large change by any standard. Or (in C++) you can wrap your functions in a class, thus avoiding necessity to change each *use* of the variable. Debugging parallel search is other issue, of course... Eugene
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