Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!zephyr.ens.tek.com!tektronix!reed!reeder
From: reeder@reed.UUCP (Doug Reeder)
Newsgroups: comp.sys.apple
Subject: Re: AE, Mandelbrot generator
Summary: points not in the set are not set false
Message-ID: <14105@reed.UUCP>
Date: 9 Feb 90 05:22:17 GMT
References: <9002071850.AA29665@en.ecn.purdue.edu>
Reply-To: reeder@reed.UUCP (Doug Reeder)
Organization: Institute of Knowledge, Jinx
Lines: 26

In article <9002071850.AA29665@en.ecn.purdue.edu> eldorado@EN.ECN.PURDUE.EDU (David D Jansen) writes:

>Could someone with fractal experience tell me why I get weird data.  It gets
>the basic shape but not quite right.  A friend of mine (a fractal "guru")
>can't make out what the problem.

>      if (((z.a * z.a) + (z.b * z.b)) <= 4) then
>        pages.bitmap[h,v]:=true
Nowhere do you initialize the bitmap to false, and Pascal does not
initialize your variables for you, so the value of any given point is
undefined when you start.  The simplest way to fix this is to add:
       else
         pages.bitmap[h,v]:=false

>    end;
>    writeln (v/ver*100:5:2,'% done');

etc.

Some pascal compilers will initialize your variables for you, but don't
depend on it.
-- 
Doug Reeder                                   USENET: ...!tektronix!reed!reeder
from ARPA: tektronix!reed!reeder@berkeley.EDU BITNET: reeder@reed.BITNET
the Little Mermaid on materialism:
I just don't see how a world that makes such wonderful things ... could be bad!