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From: Eyal &lt;efleminge@gmail.com&gt;
Newsgroups: comp.soft-sys.matlab
Subject: Identifying repeating pattern in a vector
Date: Tue, 3 Nov 2009 05:50:13 -0800 (PST)
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Hi

I have a function running a loop where a value is added to a vector at
each iteration. So, for example, if the vector is x, it could look
like:

Iteration 1: x=[1]
Iteration 2: x=[1,3]
Iteration 3: x=[1,3,2]
Iteration 4: x=[1,3,2,6]
Iteration 5: x=[1,3,2,6,2]
Iteration 6: x=[1,3,2,6,2,6]
Iteration 7: x=[1,3,2,6,2,6,2]

and so on.

As can be seen in the example above, at some point a repeating pattern
of values may appear in x; this indicates the function has entered an
infinite loop. I would like to be able to catch the pattern, say for
example after 3 repeats. In the example above, that would be when the
last 6 values of x are [2,6,2,6,2,6]; however, I do not know the
values in advance, nor do I know the length of the repeating pattern
(e.g. it could be [2,4,6,3,2,4,6,3,2,4,6,3]), though for practical
purposes three values should be sufficient to catch this error.

Can anyone suggest a way to identify this repeating pattern?

Thx
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