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.TH chain_struct 1 "September 1996" "Scilab Group" "Scilab function"
.so ../sci.an
.SH NAME
chain_struct - chained structure from adjacency lists of a graph
.SH CALLING SEQUENCE
.nf
[fe,che,fn,chn] = chain_struct(g)
[fe,che,fn,chn] = chain_struct(lp,la,ls)
.fi
.SH PARAMETERS
.TP 2
g
: graph list
.TP 3
lp
: row vector, pointer array of the adjacency lists description of the graph
(its size is the number of nodes of the graph + 1)
.TP 3
la
: row vector, arc array of the adjacency lists description of the graph
(its size is the number of edges of the graph)
.TP 3
ls
: row vector, node array of the adjacency lists description of the graph
(its size is the number of edges of the graph)
.TP 3
fe
: row vector of the numbers of the first edges starting from nodes
(its size is the number of nodes of the graph)
.TP 4
che
: row vector of the numbers of the chained edges
(its size is the number of edges of the graph)
.TP 3
fn
: row vector of the numbers of the first nodes reached by the edges of
\fVfe\fR (its size is the number of nodes of the graph)
.TP 4
chn
: row vector of the nodes reached by the edges of \fVche\fR
.SH DESCRIPTION
\fVchain_struct\fR computes the row vectors of the edge chained structure
description of the graph \fVg\fR.
It is also possible to give directly \fVchain_struct\fR the adjacency lists of
the graph. This is more efficient if the adjacency lists are already
available since \fVchain_struct\fR uses them to make computations.
The vectors \fVfe\fR, \fVche\fR, \fVfn\fR and \fVchn\fR describe the
chained structure in the following way:
\fVfe(i))\fR is the number of the first edge starting from node i
\fVche(fe(i))\fR is the number of the second edge starting from
node i, \fVche(che(fe(i)))\fR is the number of the third edge starting from
node i and so on until the value is 0
\fVfn(i)\fR is the number of the first node reached from node i
\fVch(i)\fR is the number of the node reached by edge \fVche(i)\fR.
.SH EXAMPLE
.nf
ta=[1 1 2 3 5 4 6 7 7 3 3 8 8 5];
he=[2 3 5 4 6 6 7 4 3 2 8 1 7 4];
g=make_graph('foo',1,8,ta,he);
g('node_x')=[116 231 192 323 354 454 305 155];
g('node_y')=[118 116 212 219 117 185 334 316];
show_graph(g);
[fe,che,fn,chn] = chain_struct(g)
.fi
.SH SEE ALSO
adj_lists, graph_2_mat
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