Repost of Wainwright message

[Marcus G. Daniels]

[Argh, I've turned off the majordom admin paranoia, because the
 trigger is just too light.]

"Marcus G. Daniels" wrote:
...
> I don't understand this comment.  Talking to simulation people both at UCSB
> and in bussiness (Rand Corp. and TRW), the feeling is that it is the best
> general language out for simulation.  The feeling is that Java, being
> partially interpreted, will always be a step slower and that makes it
> uNsuitable for hard core sims. 

Hmm, the simulation people I talk to all advocate Fortran90, but they're
mostly matrix-heads.

Actually, the improvements in speed of Java with JIT are what brought me
back to Swarm after trying to build similar models in a fully-compiled OO
language (Eiffel).  The latest IBM JVM (1.3) ruNs numerical code at 90%+
the speed of optimized C, so there is little reason to reject Java for
efficiency concerns.  (NOTE:  The Sun/Blackdown JVM and Kaffe aren't that
fast, but presumably they'll catch up.)  Yes, there is some overhead in
loading and interpreting the byte code, but that is a small concern in a
large long-running simulation.

For some benchmarks, see:  http://math.nist.gov/javanumerics/#benchmarks

Also, some readers might be interested in the IBM Ninja project, at
http://www.research.ibm.com/ninja

>  I'm not trying to push C++, I just
> don't understand why you think it is uNsuitable.

The main reason I reject C++ is the same reason I object to ObjC--It's too
easy to write bad (i.e. obscure and loosely typed) code, resulting in a
very long revision/debugging cycle.  If you can get the same run-time
efficiency in Java or Eiffel, why spend all your time debugging invalid
casts and silly pointer errors? I do miss multiple inheritance, but that
can usually be worked around fairly easily.

Java of course has the additional plus of portability and webability,
although the latter's not yet possible with Swarm because of the ObjC core.

-- 
Tom Wainwright
NOAA/NMFS/NWFSC
2030 S Marine Science Dr
Newport, OR 97365 USA
address@hidden

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