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Re: MPI and Java

"A.J. Rossini" wrote:
> >>>>> "e" == exa  <Eray> writes:
>     e> Well, MPI is about high performance. A '99 paper I read about
>     e> Java MPI showed it to be 20 times slower than MPI in
>     e> C/C++/FORTRAN so I don't think that's a good bet :)
>     >> And we can safely discount the gains by Java bytecompiler
>     >> technology, right :-)?
>     >>
>     e> What technology! :)
> Benchmarks are highly specific to the task.  Using statistical
> simulations as benchmarks, we've seen comparable Java and C
> performance (which I would've discounted, except it was done by one of
> our better programmers; for reference, I still find Java annoying as
> hell, compared to say, python...).

Well, maybe. But any computation that is slightly more complex than
iterating thru a single array of integers and Java will blow up. I've
done two things on Java: a phong renderer and a graph based data
clustering algorithm in Weka framework. The first I did when Java
was first released and the second when I believed it had matured
enough (IBM's latest JDK, 7-8 months ago, platform Linux. All that
bytecompilation stuff included.)

You can't even compare the latter to a graph partitioning algorithm I
did in C++, Java will consume insane amounts of memory and turn your bit
grinding pentium into a 6502. The thing is that Java is fitting for
writing web based chatrooms, but not HPF. :)

Point me to Java BLAS3 routines that scale up to ASCI grade supercomputers,
and displays performance within a const. factor of 2 wrt finest code.... and
then I'll believe that Java might enter the game. Which I don't believe is
possible due to some fundamental design flaws that prevent a whole class of

And things like python have of course their place in tasks such as being
a glue language (wrapper around HPF codes for instance) or sys admin. tasks,
but I have seen no language that comes near the performance of a well written
C/C++ or FORTRAN program.

Of course everybody in the local CS department will believe that Java is
the language of the future including my dept. Unaware that Java offers no
fundamental improvement over any programming language being just a dumbed
down special purpose version of C++.


Eray (exa) Ozkural
Comp. Sci. Dept., Bilkent University, Ankara
e-mail: erayo@cs.bilkent.edu.tr
www: http://www.cs.bilkent.edu.tr/~erayo

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