Description of induce

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induce

PURPOSE

induce --- create induced subgraphs

SYNOPSIS

function induce(g,arg1,arg2)

DESCRIPTION

 induce --- create induced subgraphs
 induce(g,vset) --- g overwritten with induced subgraph on vset
 induce(g,h,vset) --- g overwritten with induced subgraph of h on vertex
                      set vset

CROSS-REFERENCE INFORMATION

This function calls:

• embed embed --- create an embedding for a graph
• getxy getxy(g) --- give g's embedding (or [] if g doesn't have one)
• hasxy hasxy(g) --- determine if an embedding has been created for g
• is_labeled is_labeled(g) --- determine if there are labels on vertices.
• label Assign labels to vertices of g

This function is called by:

SOURCE CODE

0001 function induce(g,arg1,arg2)
0002 % induce --- create induced subgraphs
0003 % induce(g,vset) --- g overwritten with induced subgraph on vset
0004 % induce(g,h,vset) --- g overwritten with induced subgraph of h on vertex
0005 %                      set vset
0006 
0007 
0008 global GRAPH_MAGIC
0009 
0010 if nargin == 2
0011     vset = arg1;
0012     if hasxy(g)
0013         GRAPH_MAGIC.graphs{g.idx}.xy = ...
0014             GRAPH_MAGIC.graphs{g.idx}.xy(vset,:);
0015     end
0016     if is_labeled(g)
0017         GRAPH_MAGIC.graphs{g.idx}.labels =  ...
0018             GRAPH_MAGIC.graphs{g.idx}.labels(vset);
0019     end
0020     GRAPH_MAGIC.graphs{g.idx}.array = ...
0021         GRAPH_MAGIC.graphs{g.idx}.array(vset,vset);
0022     return
0023 end
0024 
0025 h = arg1;
0026 vset = arg2;
0027 
0028 GRAPH_MAGIC.graphs{g.idx}.array = ...
0029     GRAPH_MAGIC.graphs{h.idx}.array(vset,vset);
0030 
0031 if (hasxy(h))
0032     xy = getxy(h);
0033     xy = xy(vset,:);
0034     embed(g,xy);
0035 end
0036 
0037 if is_labeled(g)
0038     label(h);
0039     GRAPH_MAGIC.graphs{g.idx}.labels = ...
0040         GRAPH_MAGIC.graphs{h.idx}.labels(vset);
0041 end

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