Re: Numerical Computation and Ada95

["Marin David Condic" <marin.condic.auntie.spam@pacemicro.com>]

I was afraid to say anything because its been so long since I regularly used
Fortran that I couldn't be sure that later versions of the language didn't
add features of which I was not aware. When I *was* a Fortran programmer and
started learning Ada, I was very impressed with the fact that Ada seemed to
have so much better support for math than did Fortran. (Aside from lack of
Log & trig at the time. :-) Certainly, Ada has added lots of new
mathematical capabilities in Ada95 only by now I don't know if Fortran has
caught up.

At the time, I was very impressed that Ada let you specify the accuracy you
required and/or check the accuracy that was available. Ada defined model
numbers and safe numbers that gave one a model for understanding how
calculations were going to be made & thus one could plan for it. Fortran
basically left the mechanics of the computations up to the machine with no
rigorous formal definition of behavior. (Or at least it was not nearly as
rigorous as the definition Ada provided.) Lots of this is a major aid in
numerical analysis when you're trying to figure out how good your
computations are going to be.

Now the numerous attributes available for numeric types as well as adding
support for decimal & modular types would have me claiming that there is
quite a bit more support in Ada for number crunching than one gets with
Fortran - but the last Fortran I used was Fortran77. If later versions have
caught up, I'd like to know about it, but I'd recommend that Fortran number
crunchers take a serious look at Ada's numeric support because they just
might find it to be superior. (That, and its hard to beat Generics for
building computations once & reusing them with different numeric types!)

MDC

--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
Web:      http://www.mcondic.com/


"Jean-Pierre Rosen" <rosen@adalog.fr> wrote in message
news:9dh4ol$s9g$1@s1.read.news.oleane.net...
> An other point I'm surprised nobody mentionned:
> Provided your compiler supports Annex F, you get guarantees about the
numerical accuracies of computations, *including* the accuracy
> of the math library.
> AFAIK, Fortran tells you nothing about the accuracy of sin, log, etc. So
if you are concerned not only by fast results, but also by
> accurate results, Ada is a big winner.
>