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Copyright (C) 2009-2012 Gabor Csardi <csardi.gabor@gmail.com>
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334 Harvard street, Cambridge, MA 02139 USA
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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#ifndef IGRAPH_DATATYPE_H
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#define IGRAPH_DATATYPE_H
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# define __BEGIN_DECLS extern "C" {
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# define __END_DECLS }
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# define __BEGIN_DECLS /* empty */
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# define __END_DECLS /* empty */
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#include "igraph_types.h"
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#include "igraph_vector.h"
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* \brief The internal data structure for storing graphs.
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* It is simple and efficient. It has the following members:
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* - <b>n</b> The number of vertices, reduntant.
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* - <b>directed</b> Whether the graph is directed.
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* - <b>from</b> The first column of the edge list.
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* - <b>to</b> The second column of the edge list.
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* - <b>oi</b> The index of the edge list by the first column. Thus
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* the first edge according to this order goes from
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* \c from[oi[0]] to \c to[oi[0]]. The length of
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* this vector is the same as the number of edges in the graph.
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* - <b>ii</b> The index of the edge list by the second column.
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* The length of this vector is the same as the number of edges.
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* - <b>os</b> Contains pointers to the edgelist (\c from
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* and \c to for every vertex. The first edge \em from
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* vertex \c v is edge no. \c from[oi[os[v]]] if
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* \c os[v]<os[v+1]. If \c os[v]==os[v+1] then
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* there are no edges \em from node \c v. Its length is
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* the number of vertices plus one, the last element is always the
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* same as the number of edges and is contained only to ease the
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* - <b>is</b> This is basically the same as <b>os</b>, but this time
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* for the incoming edges.
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* For undirected graph, the same edge list is stored, ie. an
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* undirected edge is stored only once, and for checking whether there
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* is an undirected edge from \c v1 to \c v2 one
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* should search for both \c from=v1, \c to=v2 and
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* \c from=v2, \c to=v1.
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* The storage requirements for a graph with \c |V| vertices
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* and \c |E| edges is \c O(|E|+|V|).
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typedef struct igraph_s {
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igraph_bool_t directed;
added
removed
include/igraph_datatype.h
