trans_topologyMat2edgeTable(topologyMatrix)

% trans_topologyMat2edgeTable
% 
% Usage: [edgeTable] = trans_topologyMat2edgeTable(topologyMatrix)
%
% Abstract: This function converts a "topology matrix" in a "edges matrix". 
% We translate the information about the physical topology from a format
% "topology matrix' (matrix of 1's and 0's where each entry (i,j)indicates 
% if there is a physical link from the node i to the node j if the entry is
% '1'.) to a format "edges matrix" (matrix where each row is a link and the
% first and second column of each row are respectively the origin node and 
% the destination node).
%
% Arguments:
% o	In: 
%  topologyMatrix(NxN): N-by-N integer matrix. Graph of the network topology 
%   (physical topolgy of links or vurtual topology of edges) of nodes and edges, 
%   where N is the number of nodes. As entry (i,j) is the number of edges existing 
%   from the node i to the node j. It is usually 1 or 0, in case of the edge exists 
%   or not respectively. As agreement the values of main diagonal are
%   established to 0.
%
% o	Out: 
% . edgeTable(M,2): M-by-2 integer matrix. Each row is an edge (physical link 
%   or lightpath) 'm', where the first and second columns of each row are the 
%   origin node 'x' and destination node 'y' of this edge 'm' respectively and
%   M is the number of physical links or lightpaths if the network topology
%   is physical or virtual respectively.


function [edgeTable] = trans_topologyMat2edgeTable(topologyMatrix)

if (nargin==0),  help trans_topologyMat2edgeTable;return, end %help calling
if (nargin~=1),  error('1: Incorrect number of arguments.'),end %Number of input arguments different of 1

[destinationNode originNode]=find(topologyMatrix'>0);
edgeTable=[originNode destinationNode];