From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,bcdac28207102750,start
X-Google-Attributes: gid103376,public
From: David Starner <dstarner98@aasaa.ofe.org>
Subject: Re: Ada95 speed
Date: 1999/05/17
Message-ID: <3740C7B1.4CD68529@aasaa.ofe.org>#1/1
X-Deja-AN: 479285436
Content-Transfer-Encoding: 7bit
References: <3740C535.7C6200A8@gte.net>
X-Accept-Language: en
Content-Type: text/plain; charset=us-ascii
X-Complaints-To: abuse@worldnet.att.net
X-Trace: bgtnsc02.worldnet.att.net 926999691 17557 12.72.227.143 (18 May 1999
 03:54:51 GMT)
Organization: AT&T WorldNet Services
Mime-Version: 1.0
NNTP-Posting-Date: 18 May 1999 03:54:51 GMT
Newsgroups: comp.lang.ada
Date: 1999-05-18T03:54:51+00:00
List-Id: <comp.lang.ada>



"Clifford J. Nelson" wrote:
> 
> Ten years ago a Mandelbrot set computation and display on a 1200x700
> screen with eight bit color took six seconds in C on a MacIIfx.
> 
> The following computations (leaving out all the with statements that you
> need for the Mac) take ten seconds on an iMac 266 MHertz Mac OS 8.5.1
> with the CodeBuilder Ada95 GNU from Tenon. I think it should run ten
> times faster.

Was the code identical? I've had two Mandelbrot generators on the same
system, and one took hours and one took seconds to do the Mandelbrot.
Since the later was carefully and extensively tuned (cf. Fractint), I
get the impression that the comparision code may have been similarily
tuned. 

>           exit when (abs( Z)) > 2.0;

This line is probably the problem. The C code probably never did a sqrt;
most likely, the code looked like (z.i* z.i + z.r * z.r) > 4.0. Do the
same thing in Ada, and you'll probably see a huge improvement.