Newsgroups: comp.parallel.pvm From: Lars Rzymianowicz Subject: Re: NESL Organization: Dept. of Computer Science, University of Mannheim, Germany Date: Tue, 26 May 1998 09:06:53 +0200 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <356A6A0D.B0F144CD@mufasa.informatik.uni-mannheim.de> Daniel Pfenniger wrote: > Has anybody experience with NESL? > ... that for some applications ... might degrade performance significantly. It does. 3 years ago i coded some small apps (e.g. NAS Benchmark) with NESL and compared the runtime against C. NESL is very, very slow. The reasons are: - the NESL compiler generates an intermediate vector code, which is interpreted by a virtual vector machine (think of JVM) - so its main target are vector machines. I guess, NESL's performance will be much higher on those machines than on a WS, but it gets harder to find those dinosaurs... > The simplicity of coding parallel algorithms is however attractive > (a quicksort algorithm is coded in ten lines with NESL in comparison > of 1700 with MPI). ^^^^ First, you don't seem to be an experienced MPI programmer, ey? ;-) NESL (or any other data-parallel language) might be nice for some apps, but you can't implement task-parallel apps with them. The portability and versatility of Message Passing Libs like MPI or PVM far outweighs the "might be" better performance of data-parallel languages on some problems. Lars -- email: lr@mufasa.informatik.uni-mannheim.de Homepage: http://mufasa.informatik.uni-mannheim.de/lsra/persons/lars/