Description of sladjlist2edgeset

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sladjlist2edgeset

PURPOSE

SLADJLIST2EDGESET Converts the adjacency list to edge set

SYNOPSIS

function edges = sladjlist2edgeset(targets, sch)

DESCRIPTION

SLADJLIST2EDGESET Converts the adjacency list to edge set

 $ Syntax $
   - edges = sladjlist2edgeset(targets, sch)

 $ Arguments $
   - targets:      The targets in adj list (length-n cell array)
   - sch:          The scheme of conversion
                   - 0: no value -> no value
                   - 1: no value -> has value
                   - 2: has value -> no value
                   - 3: has value -> has value
   - edges:        The edge set (nedges x 2 or nedges x 3 matrix)
 
 $ Remarks $
   - an internal function for graph representation conversion.
     no checking of input arguments would be performed.

 $ History $
   - Created by Dahua Lin, on Sep 9, 2006

CROSS-REFERENCE INFORMATION

This function calls:

• slexpand SLEXPAND Expand a set to multiple instance

This function is called by:

• sladjmat SLADJMAT Constructs the adjacency matrix representation of a graph
• sledgeset SLEDGESET Construct the edge set representation of a graph
• slnngraph SLNNGRAPH Constructs a nearest neighborhood based graph

SOURCE CODE

0001 function edges = sladjlist2edgeset(targets, sch)
0002 %SLADJLIST2EDGESET Converts the adjacency list to edge set
0003 %
0004 % $ Syntax $
0005 %   - edges = sladjlist2edgeset(targets, sch)
0006 %
0007 % $ Arguments $
0008 %   - targets:      The targets in adj list (length-n cell array)
0009 %   - sch:          The scheme of conversion
0010 %                   - 0: no value -> no value
0011 %                   - 1: no value -> has value
0012 %                   - 2: has value -> no value
0013 %                   - 3: has value -> has value
0014 %   - edges:        The edge set (nedges x 2 or nedges x 3 matrix)
0015 %
0016 % $ Remarks $
0017 %   - an internal function for graph representation conversion.
0018 %     no checking of input arguments would be performed.
0019 %
0020 % $ History $
0021 %   - Created by Dahua Lin, on Sep 9, 2006
0022 %
0023 
0024 %% get J and V
0025 
0026 n = length(targets);
0027 jv = vertcat(targets{:});
0028 
0029 if ~isempty(jv)
0030     if sch == 1
0031         nedges = size(jv, 1);
0032         jv = [jv, ones(nedges, 1)];
0033     elseif sch == 2
0034         jv = jv(:,1);
0035     end
0036 else
0037     edges =[];
0038     return;
0039 end
0040         
0041 %% add I
0042 
0043 nums = zeros(n, 1);
0044 for i = 1 : n
0045     cinds = targets{i};
0046     if ~isempty(cinds)
0047         nums(i) = size(cinds, 1);
0048     end
0049 end
0050 ic = slexpand(nums);
0051 edges = [ic, jv];
0052 
0053

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