Hi Michael, Without --fast the compiler generates runtime checks, which slows down execution time.
Please compile with the --fast flag and see how much execution time improvement there is. Thanks Tom MacDonald On Fri, 15 Aug 2014, Tom MacDonald wrote: > Hi Michael, > > Thank you for your interest in Chapel! It's good to hear you are > studying high performance programming languages. > > Are you compiling your Chapel program with the --fast option? > > We need to know that before looking deeper. > > Thanks > > Tom MacDonald > > On Fri, 15 Aug 2014, Michael Dietrich wrote: > >> Hello, >> >> I'm working with Chapel due to my bachelor thesis about high >> performance programming languages. My current task is to implement a >> particle simulation program of which I already have the code in C. It >> includes two possible algorithms for calculating the force acting onto >> the particles: A simple but ineffective one and the >> Barnes-Hut-Algorithm [1] which is much faster but a bit more >> complicated. The other calculations aren't that complex so for me only >> the calculation of force is important. >> >> I implemented the simple algorithm at first. For comparing the serial >> and parallel execution time I surrounded everything with a >> serial-statement, evaluating a bool variable I have to set in the >> command line. I didn't implement the multi locale improvement yet so >> it runs only on a dual core PC, using forall-loops. Finally the >> parallel one only needed half of the time of the serial, yay. >> >> I continued with Barnes-Hut. This one was a bit more work because the >> maintenance of the tree-structure leaves a lot of opportunities for >> mistakes. After a bit more time it was working as well. >> My issue is about the parallel execution time of this algorithm. Like >> in the other one I replaced the crucial for-loop with a forall-loop >> (the serial-statement surrounds the whole program). The problem is, >> that the parallel execution time is similar to the serial one, >> sometimes even longer. >> Of course I don't want you to read through all my code, but could you >> tell me some possible reasons, why this effect may occur? >> >> thank you very much >> bye >> Michael >> >> >> [1] http://beltoforion.de/barnes_hut/barnes_hut_en.html >> >> >> ------------------------------------------------------------------------------ >> _______________________________________________ >> Chapel-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/chapel-users >> > > ------------------------------------------------------------------------------ > _______________________________________________ > Chapel-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/chapel-users > ------------------------------------------------------------------------------ _______________________________________________ Chapel-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/chapel-users
