Re: [Swarm-Modelling] Floating point arithmetic

[Marcus G. Daniels]

Russell Standish wrote:

> What's that got to do with no-one using parallel Java? Plenty of people
> do parallel Fortran or parallel C/C++?
>  
The distinction is between parallel application code running in threads 
vs. code that runs in parallel by using distributed objects.  The former 
has low latency (threads) while the latter is over-the-network 
(typically much higher latency).  Java RMI aims to be a user-friendly 
high level interface while MPI (C/Fortran) is a more 
performance-friendly programming model as it doesn't do as much.  
Amdahl's law is exacerbated with RMI (relative to MPI) due to software 
overhead of marshalling calls and increased latency.  I don't believe 
there are any Java language dialects that have compiler implementations 
of the quality of OpenMP (e.g. for C/Fortran compilers by Sun, Portland 
Group, Cray, etc.) so as to extract fine-grained parallelism from loops 
and the like (and using kernel threads to schedule the concurrent parts 
of loops, futures, etc).