Re: Numerics in Ada and C++

[Brian Rogoff <bpr@shell5.ba.best.com>]

There is some discussion of this topic in the Ada FAQ, and I think one of
DEC's compiler experts reports that well programmed Ada was just as fast 
as F77, given a decent compiler of course. Ada does not have the same 
aliasing problems that C and C++ have, and Ada 95, which is more
permissive than Ada 83 in this regard, forces you to explicitly specify 
aliasing when you want it. 

Incidentally, I was looking for a better Fortran several years ago when I 
"discovered" Ada, after being disappointed by C++. I don't know what the
current state of C++ compilers is wrt templates, but in 1995 it was
abysmal. I don't think I'd switch now, even if all C++ compilers conformed
to the draft ISO standard. Ada 95 is just a *much* better language IMO,
despite numerous little (and big ;-) flaws. Particularly for numerics.

-- Brian 

On Mon, 19 Jan 1998, Harry Erwin wrote:

> The new standard for C++ introduces a number of numerics template
> classes (valarray<>, slice<>, etc.) that are intended to implement smart
> arrays built around simple classes that lack side-effects and aliasing
> for the new and delete operators. This has been done so that optimizing
> compilers can generate code for operations on those classes that
> approaches FORTRAN-77 in efficiency. Experience in computational
> applications of C++ has indicated that 'mid-level' C++ code (class code
> involving branching and temporaries) has been particularly inefficient
> and hard for compilers to optimize, and these features were added to
> help solve the problem. My question here is whether Ada encounters the
> same problems.
> 
> -- 
> Harry Erwin, herwin@gmu.edu, http://osf1.gmu.edu/~herwin, Senior
> Software Analyst for the FAA, PhD candidate modeling how bats 
> echolocate and lecturer for CS 211 (data structures and advanced C++).
> 
>