Re: Can it be! A bug in "for"?

From	ken <ken@spamcop.net>
Newsgroups	comp.lang.postscript
Subject	Re: Can it be! A bug in "for"?
Date	2011-11-04 08:01 +0000
Message-ID	<MPG.291dac0b8721dac4989866@usenet.plus.net> (permalink)
References	<b0f2ade7-c738-401f-8b72-0615f50f6a96@r28g2000yqj.googlegroups.com>

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In article <b0f2ade7-c738-401f-8b72-0615f50f6a96
@r28g2000yqj.googlegroups.com>, mijoryx@yahoo.com says...
 
> To be fair, I only just fixed mine yesterday. But now that I can get
> phase pyramid gradient where I expected it.

From the PLRM, p596 (3rd edition), the 'for' operator:

"Beware of using real numbers instead of integers for any of the first 
three operands. Most real numbers are not represented exactly. This can 
cause an error to accumulate in the value of the control variable, with 
possibly surprising results. In particular, if the difference between 
initial and limit is a multiple of increment, as in the last example, 
the control variable may not achieve the limit value."

Which seems to me to be exactly the situation here.....

So its not a bug, its documented behaviour :-)

		Ken

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Can it be! A bug in "for"? luser- -droog <mijoryx@yahoo.com> - 2011-11-03 17:11 -0700
  Re: Can it be! A bug in "for"? A D <amd1234@fastmail.com.au> - 2011-11-04 13:58 +1100
    Re: Can it be! A bug in "for"? luser- -droog <mijoryx@yahoo.com> - 2011-11-03 22:18 -0700
      Re: Can it be! A bug in "for"? ken <ken@spamcop.net> - 2011-11-04 08:02 +0000
        Everybody stop panicking! It's not a bug. (was Re: Can it be! A bug in "for"?) luser- -droog <mijoryx@yahoo.com> - 2011-11-04 01:22 -0700
      Re: Can it be! A bug in "for"? bonomi@host122.r-bonomi.com (Robert Bonomi) - 2011-11-07 16:22 -0600
  Re: Can it be! A bug in "for"? ken <ken@spamcop.net> - 2011-11-04 08:01 +0000

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