Re: Ada vs Fortran for scientific applications

[Pascal Obry <pascal@obry.net>]

Nasser Abbasi a �crit :

> I also found this interesting note about some research done at IBM for 
> paralalizing Ada for numerical work
> 
> "Parallelism in scientific applications can most often be found at the loop 
> level. Although Ada supports parallelism via the task construct, its 
> coarseness renders it unsuitable for this light-weight parallelism."

And this is talking only about a small part of the total application. In
some applications I know where OpenMP is used to do parallel computing
the gain is 20% or 30%. Why ? Because most of the application is not
doing vector computing! This is often only a small part of an
application. The application needs to read data, prepare them, do some
computation, eventually communicate with some other applications, do
some more computations... write the data, do some 2D/3D display... At
this level of parallelism Ada tasking is a really nice solution. The
fork/join model of OpenMP is not that efficient and certainly not a
general purpose model.

We are not in a world of vector-oriented architecture and vectorizing
compiler (Cray, Fujitsu) but in a multi-processor or dual-core
cluster/grid. I'm not sure IBM would say the same thing today...

Pascal.

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