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From: sxc@itd.dsto.gov.au
Newsgroups: comp.lang.ada
Subject: Re: Ada and Number Crunching ?
Message-ID: <3ikfqg$6ar@fang.dsto.gov.au>
Date: 24 Feb 95 11:27:12 GMT
References: <3iatre$3t1m@lamar.ColoState.EDU>
 <VLADIMIR.95Feb20234429@speedy.intrepid.com>
Organization: DSTO Australia
NNTP-Posting-Host: shekel.dsto.gov.au
Date: 1995-02-24T11:27:12+00:00
List-Id: <comp.lang.ada>

In article <VLADIMIR.95Feb20234429@speedy.intrepid.com>,
Vladimir Vukicevic <vladimir@speedy.intrepid.com> wrote:
>
>As regarding code speed, I'm currently writing a ray tracer completely
>in Ada 95. (Will take full advantage of tasking [as soon as I get that
>pthreads working for linux..] as well as distributed processing, etc.)
>The code runs at about the same speed than a similar ray tracer
>written completely in C++. However, considering that the ada compiler
>in question is gnat, and the C++ compiler is g++, this isn't much of a
>statistic, since they both use the same optimization engine and back
>end (gcc's). :-)

Actually, I think that Vladimir has an interesting point

  Approximately equivalent Ada and C++ programs, when compiled with 
  compilers that use the same backend / optimiser technology, seem
  to run in approximately the same time. 

Now if there was some way to remove some of the hand-waves in the 
above, he may be able to arrive at a meaningful datapoint.  For 
example:

  1)  Are the Ada and C++ programs really comparable; i.e. they do 
  they use the same algorithms and data structures, and have they 
  had similar tuning effort expended on them?

  2)  Are the back-end optimisers really identical?  (Do they do
  any C++ or Ada specific optimisation?)

  3)  What are the actual runtimes?  (Are they dominated by CPU time?)

-- Steve