Re: C is 'better' than Ada because...

[clodius@hotspec.lanl.gov (William Clodius)]

In article <01bb7fd4$6a0f4300$87ee6fce@timpent.airshields.com> "Tim
Behrendsen" <tim@airshields.com> writes: 

<snip>

   I had an [ex-]employee who wrote the slowest code on the face of
   the earth.  Because of performance problems in our application,
   I went through and analyzed his code.  The man almost never used
   pointers, and almost always used array accesses.  These algorithms
   were much more complex that the trivial examples we've been
   talking about.

   I rewrote the subroutines to use pointers, and with an eye toward
   easy optimization by the compiler.  The algorithms used were
   exactly the same; I just reworked the stylistic expression of them.
   I didn't view the assembly language output, or anything processor
   specific like that.  I simply coded things in a straightforward
   data-flow sort of way, keeping the amount of context information
   that the compiler needed at any one point in the subroutine to
   a minimum.

   I was easily able to get 3-4x performance improvements.

<snip>

This anecdote by itself says nothing. It says that you had an employee
wrote slow code and that he used arrays. Unfortunately, because you
never determined the specific sources of the inefficiencies, it does
not say that the slow code was due to the use of arrays. It could very
well be due to the misuse of arrays, in particular if he used column
major order instead of C's preferred row major order, or due to
entirely different reasons. It is possible for a knowledgeable person
to write very efficient code using arrays.
-- 

William B. Clodius		Phone: (505)-665-9370
Los Alamos National Laboratory	Email: wclodius@lanl.gov
Los Alamos, NM 87545