Re: Ada for numerics computation (i.e. forget Fortran ?)

[mgk25@cl.cam.ac.uk (Markus Kuhn)]

In article <372083A1.45A5EB97@t-online.de>, HNBeck@t-online.de (Hans N. Beck) writes:
|> does anyone has experiences with Ada and numerical
|> applications ?

Have you seen

  http://amok.ast.univie.ac.at/~stift/stift_home.html

which is a web page that propagates the use of Ada95 in
astrophysics number crunching.

|> Does Ada fit for this?

It think it does! You have all the types available (including complex),
you have a better exception handling than in Fortran, and with tasks,
you have a powerful construct for using parallel processors. Ada is
certainly much better suited than C, which thanks to the array/pointer
duality prevents many of the strong optimizations that number-crunching
applications need on modern RISK architectures. C implicitely assumes
that arrays have to be stored always in RAM (as opposed to registers),
while compilers can handle non-aliased Ada arrays much more flexible.

(I actually wonder, whether GNAT 3.11p does produce more efficient
code for non-aliased arrays than the corresponding C code, or whether
GNAT limits itself to the optimization capabilities of gcc.)

|> It's not only a question of types available, but also
|> of efficiency (speed) of the compilers.

You get Ada compilers today that are quite comparable in efficiency
with C compilers. On more exotic architectures such as super
computers, you might not find the same level of optimization yet
as it is available for Fortran 77 compilers. It depends a lot on the
architecture.

Markus

-- 
Markus G. Kuhn, Computer Laboratory, University of Cambridge, UK
Email: mkuhn at acm.org,  WWW: <http://www.cl.cam.ac.uk/~mgk25/>