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From: roberson@ibd.nrc-cnrc.gc.ca (Walter Roberson)
Newsgroups: comp.soft-sys.matlab
Subject: Re: Question on Iteration variables means?
Date: Thu, 15 May 2008 17:05:34 +0000 (UTC)
Organization: National Research Council Canada - Conseil national de rechereches Canada
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In article <g0gl13$v4i$1@news.cn99.com>, asm23  <asmwarrior@gmail.com> wrote:
>hi, I'm new to this forum, I want to know the meaning of these variables 
>for iteration.

>such as:

>X(k|k-1)
>X(k|k)
>X(k-1|k-1)
>....

>What's the difference between them? Can someone explain it? thank you 
>very much.

I think you must have miscopied or mistyped, as those are quite
unlikely to come up in real code in the form written.

'|' is bitwise 'or'. Any value bitwise or'd with itself is going to
be the same value. Thus, X(k|k) would be the same X(k), and
X(k-1|k-1) would be the same as X(k-1).

k|k-1 has some interesting mathematical properties in binary, but 
it is fairly unlikely that you have described the question correctly
so I will not describe the mathematical properties. k&k-1 has more
interesting properties and sometimes occurs in code, but k|k-1 seldom
does.

-- 
  "The whole history of civilization is strewn with creeds and
  institutions which were invaluable at first, and deadly
  afterwards."                                -- Walter Bagehot