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From: asm23 <asmwarrior@gmail.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Question on Iteration variables means?
Date: Sat, 17 May 2008 15:42:57 +0800
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John D'Errico wrote:
> roberson@ibd.nrc-cnrc.gc.ca (Walter Roberson) wrote in message 
> <g0hqgu$qp0$1@canopus.cc.umanitoba.ca>...
>> In article <g0gl13$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.
> 
> I would not assume its a typo, merely not
> useful as Matlab syntax.
> 
> These may be notations that are valid in
> some other context, but the context is all
> important. We cannot know what is meant
> out of context.
> 
> John
Thanks for your two reply, I notices that I have made a mistake, the 
X(k|k-1) is not the matlab code, they have exist in Kalman filter 
Algorithms, recursion formula often use this as some estimated value or 
expected value. But I don't know what's their meanings.