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# st: Mata and subsets...

 From Matthew Baker <[email protected]> To [email protected] Subject st: Mata and subsets... Date Thu, 1 Mar 2012 15:03:47 -0500

```Dear Listers --

I have a question about obtaining subsets and their complements in
mata. To be clear, what I am trying to do is get a listing of both the
subsets and their corresponding complements.

For example,
mata
mm_subsets(4,2)

gives me the subsets:
1   2   3   4   5   6
+-------------------------+
1 |  1   1   1   2   2   3  |
2 |  2   3   4   3   4   4  |
+-------------------------+

But the question is: is there also an (efficient, general) way to
obtain the corresponding complements:

1   2   3   4   5   6
+-------------------------+
1 |  3   2   2   1   1   1  |
2 |  4   4   3   4   3   2  |
+-------------------------+

I'm hoping for a general method that doesn't depend upon having four
items or the two-element subsets but am baffled about how to do this
without looping, etc.

Matt Baker

--
Dr. Matthew J. Baker
Department of Economics
Hunter College and the Graduate Center, CUNY
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```