Fortran vs. C for numerical work (SUMMARY)

[Mark A Terribile]

> > ... To access a random element of the array takes two additions and two
> >memory references. In contrast, to access a random element of a flat array
> >takes two additions, a multiplication, and a memory reference. On most
> >widely used machines, a multiplication is quite a bit slower than a
> >memory reference, particularly a cached memory reference.  ...

>     With respect to speed, almost all machines that I have used during
>     the last 25 or so years have had faster multiplications than
>     memory accesses. (I have been doing mostly scientific stuff.) ...

Please note that superscalar machines may change this again!  If a superscalar
machine has fewer multiplication resources than instruction pipelines, the
memory lookup may once again win, depending upon how much other stuff is done
to the datum being looked up.  Superscalar may not be a factor for the very
fastest machines (immersion cooled, GaAs, ECL, ballistic semiconductor,
whatever) but it will probably become more important for engineering work-
stations and for the second tier of fast machines (mini-supers, whatever).

But then, I could be wrong ...

Say, whatever happened to the Numerical C Extensions Group?
-- 

 (This man's opinions are his own.)
 From mole-end				Mark Terribile