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Subject: Re: What does m('ABC') do?
Date: Mon, 13 Apr 2009 12:00:17 +0000 (UTC)
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"Preet Desai" <preet.desai.nospam@matchworks.com> wrote in message <gru2dd$tu$1@fred.mathworks.com>...
> I'm trying to figure out how to make graphs with sparse matrices (like shown in the bionformatics functions), but I have no idea what
> 
> m('ABC') = [1 2 3] does. I get a 1x67 matrix with the last three numbers (1,2,3)...
> Where did 67 come from? Please help me out with this... or tell me what to search for, for more information.
> 
> 
> Preet

Preet:
"m" is a convenience index vector that helps you define a graph when node IDs are characters, lets say you want to create a graph with three nodes ('A','B','C') and three edges ('A->B','C->A','B->C'), then you can use 'm' to create the indices for sparse:

sparse(m('ACB'),m('BAC'),1,3,3)

ans =

   (3,1)        1
   (1,2)        1
   (2,3)        1

Of course you could have also use:

sparse([3 1 2],[1 2 3],1,3,3)

ans =

   (3,1)        1
   (1,2)        1
   (2,3)        1

Lucio