Re: Directed Graph from Adjacency Matrix

• To: mathgroup at smc.vnet.net
• Subject: [mg58805] Re: [mg58783] Directed Graph from Adjacency Matrix
• From: Murray Eisenberg <murray at math.umass.edu>
• Date: Tue, 19 Jul 2005 04:10:14 -0400 (EDT)
• Organization: Mathematics & Statistics, Univ. of Mass./Amherst
• References: <200507180721.DAA23417@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```    Needs["DiscreteMath`Combinatorica`"]

a = {{0, 1, 0}, {0, 0, 1}, {1, 0, 0}};
â??Graph:<6, 3, Directed>â??
ShowGraph[%]
(* output shows a directed cycle on 3 vertices *)

However:

mat = ToAdjacencyMatrix[Cycle[3, Directed -> True]]
{{0, 1, 1}, {1, 0, 1}, {1, 1, 0}}

g = FromAdjacencyMatrix[mat, Type -> Directed]
â??Graph:<6, 3, Directed>â??
ShowGraph[g]
(* the complete directed graph on 3 vertices with each edgedirected both
ways *)

In view of the preceding, you may want to use adjacency lists, rather
than the adjacency matrix, for directed graphs.

confused wrote:
> I am new to Mathematica.  Here is my question.  How would I get a
> directed graph from an adjacency matrix?  For instance, the 3x3 matrix
> {{0,1,0},{0,0,1},{1,0,0}} defines a directed 3-cycle, but when I try to
> turn it into a graph using FromAdjacencyMatrix, Mathematica returns a
> graph with only two edges.
>
> Thank you.
>
>

--
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305

```

• Prev by Date: Re: Trace[ Through [ (Max - Min) [ {1, 2, 3, 4, 5} ] ] ]
• Next by Date: Re: Validating functions input