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Topic: nchoosek all pairwise combinations
Replies: 10   Last Post: Nov 27, 2012 7:46 AM

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Jos

Posts: 1,266
Registered: 10/24/08
Re: nchoosek all pairwise combinations
Posted: Nov 27, 2012 4:40 AM
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"Jerry " <jerrycholo@gmail.com> wrote in message <k91ej5$bp5$1@newscl01ah.mathworks.com>...
> Hello,
>
> There is a vector
>
> A=['a', 'b', 'c', 'd','e']
>
> I would like to make a square matrix of all paiwise interactions of this vector:
>
>
> a b c d e
> a aa ba ca da ea
> b ab bb cb db eb
> c ac bc cc dc ec
> d ad bd cd dd ed
> e ae bd ce de ee
>
> However, nchoosek allow me to create only half of this matrix. Is there any function to make all these possible interactions within "A"?
>
> Thanks,
> Jerry


There are many ways to achieve such a matrix, but you should think about how you would store your data. Do you really want a character matrix?

A very easy way to obtain the interactions would be using NDGRID

A = 'abcde'
[B1, B2] = ndgrid(A)

which stores the interactions in two separate yet related matrices ...
It all depends on what you want to do with the result!

~ Jos



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