>> It would be helpful for me to understand what type of potential
>> applications you are thinking of ...
>>
>> Are you thinking of Jmol for viewing molecules?
> Yes. We want to develop a kind of CAD tool for designing our own
> molecules from the bottom up.
Hmmm ... interesting ...

> We call it a Computer Aided Molecular Design tool.
Sounds like it is more important that you look at CDK than at Jmol.

> We also want to use it to display results of molecular
> modelling packages, which ones are unknown at the moment but we are
> thinking about VASP?
I don't know anything about this kind of thing.

> We also want to develop our own scripting
> language  (probably in Python using Jython).
Very good. You will need to build some powerful tools.

>> is it in the context of an applet or of a standalone application?
> Standalone application.
OK

>>> I would be grateful Miguel if you could give me more details about
>>> this new 3D engine you are working on. It would help me defending our
>>> possible co-operation to the other critical project members.
>>
>>You said 'defending' ... what else are you looking at?
>
> Nothing at the moment! I have to defend my proposition of using Java
> instead of some other language to develop our software. There are
> others
> in our group who would prefer to do it in C or C++.
> We want our software to run on Windows and Linux systems at least.
> Speed
>  is in fact the only factor that works against using Java for our
> project  but I think looking at the demo of your new engine that we
> should go for  it.
Runtime speed is *not* a factor.

I think I may have said this in my previous email ... I think that for the
level of your application, Java code is only 10-20% slower. You are not
writing systems code.

Tell one of your developers to take a few days, write some benchmarks, and
test it for himself/herself. Java will be slightly slower, but not enough
to really matter.

What matters for your project is developer productivity. I think that your
developers will be more productive using Java, especially your best
developers.

Java *will* be slower if the developers are wasteful in generating lots of
garbage at runtime. But those same developers would have cost you more
*development time* in the C++ world.

I think that Java losing mindshare and going "out of fashion" is a more
legitimate concern.

See additional comments below.

> There are just too many benefits in using Java.

> Jmol is also, I think, one of the better examples of a �general�
> molecular visualisation package. Not too specific, not too big so it
> should be fairly easy to strip it from the parts we will not need for
> our software.
> Did you test Jmol on a Linux or other unix system?
Most of my development is done on RedHat Linux. When I am traveling I do
development on a Win32 laptop. Egon uses a Sun.

> Are you developing with the latest J2SE release (1.4.2_01)?
Yes

> I have noticed a considerable improvement in speed compared to 1.4.
It is good to hear that you think it is faster. Sun PR said that it was
faster.  The specific graphics operations I want are still too slow. (I
said that the graphics operations are slow, not that Java is inherently
slow.)


>> But it would be good to have someone else take a critical look at it,
> or to use it heavily.
> We will do that! Not to worry! :-)
Good.


Now, for my random thoughts. In fact, my blunt advice:

I spent many years programming in C and C++ ... I have been programming in
Java for 11 months. Frankly, I would not dream of doing your project in
C++.

You want to be cross-platform, Win + *nix. Which offers a more portable
cross-platform *environment* of systems calls?

You want to build a complicated CAD system. This is not a low-end system,
it is a high-end system. Your target users will have good hardware,
multiple CPUs. You will want to use those CPUs to check the validity of
structures in real-time. Which offers a more portable way of managing
threads, Java or C++?

You want to do some distributed computed ... in the form if your screen
saver. Which language is better suited for managing distributed processes?

Something *very* important for you should be availability of molecular
modeling libraries. I honestly have no idea whether Java or C++ has better
stuff. But this is *much* more important than measly performance
considerations.

I believe that C++ has an advantage over Java in the area of OpenGL
support, but you are not currently thinking of using OpenGL.

Finally, I am going to going to say something that may surprise you.

I don't think you should use Jmol ... you should use Java3D (or OpenGL if
you choose the C++ path).

You are building a complex system that is targeted at users who will be
running on high-end hardware. And we are talking about high-end hardware
when you start to deplay 2 or 3 years from now. Your target users will
*absolutely* have 3D graphics hardware. You should use it.

I am not a fan of Java3D ... as a broad market product. Nevertheless it
does work (I assume) and it does have its place. And I think its place is
for applications like yours. Java3D will slowly gain broader support and
acceptance over the coming years.

Training ... I am sure that you are hoping to have a team of developers.
If you use Java3D/OpenGL then it will be much easier to train your
developers and get them up to speed.

Jmol is small and attractive and a more complete package for rendering
molecules. But I think your project will outgrow it quickly.

In summary, if it was my project
 - I would decide which chemical modeling libray to use. If there was a
   clear winner in the C++ world that may sway me to use C++
 - I would use Java over C++
 - I would use Java3D or OpenGL instead of jmol

Let me know what you think.
Don't hold back ... I didn't :-)

Miguel


>
> Regards,
>
> Val�re
>
>
>
>
>
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