ext/OGDF/ogdf/planarity/EmbedderMinDepthMaxFaceLayers.h

   1 /*
   2  * $Revision: 2584 $
   3  *
   4  * last checkin:
   5  *   $Author: gutwenger $
   6  *   $Date: 2012-07-12 02:38:07 +0200 (Do, 12. Jul 2012) $
   7  ***************************************************************/
   8
   9 /** \file
  10  * \brief Computes an embedding of a graph with minimum depth and
  11  * maximum external face (plus layers approach).
  12  *
  13  * \author Thorsten Kerkhof
  14  *
  15  * \par License:
  16  * This file is part of the Open Graph Drawing Framework (OGDF).
  17  *
  18  * \par
  19  * Copyright (C)<br>
  20  * See README.txt in the root directory of the OGDF installation for details.
  21  *
  22  * \par
  23  * This program is free software; you can redistribute it and/or
  24  * modify it under the terms of the GNU General Public License
  25  * Version 2 or 3 as published by the Free Software Foundation;
  26  * see the file LICENSE.txt included in the packaging of this file
  27  * for details.
  28  *
  29  * \par
  30  * This program is distributed in the hope that it will be useful,
  31  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  32  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  33  * GNU General Public License for more details.
  34  *
  35  * \par
  36  * You should have received a copy of the GNU General Public
  37  * License along with this program; if not, write to the Free
  38  * Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  39  * Boston, MA 02110-1301, USA.
  40  *
  41  * \see  http://www.gnu.org/copyleft/gpl.html
  42  ***************************************************************/
  43
  44 #ifdef _MSC_VER
  45 #pragma once
  46 #endif
  47
  48 #ifndef OGDF_EMBEDDER_MIN_DEPTH_MAX_FACE_Layers_H
  49 #define OGDF_EMBEDDER_MIN_DEPTH_MAX_FACE_Layers_H
  50
  51 #include <ogdf/module/EmbedderModule.h>
  52 #include <ogdf/decomposition/BCTree.h>
  53 #include <ogdf/internal/planarity/MDMFLengthAttribute.h>
  54
  55 namespace ogdf {
  56
  57 //! Planar graph embedding with minimum block-nesting depth and maximum external face (plus layers approach).
  58 /**
  59  * See paper "Graph Embedding with Minimum Depth and Maximum External Face"
  60  * by C. Gutwenger and P. Mutzel (2004) for details.
  61  * The algorithm for minimum depth and maximum external face is combined with the
  62  * algorithm for maximum external layers which defines how to embed
  63  * blocks into inner faces. See diploma thesis "Algorithmen zur
  64  * Bestimmung von guten Graph-Einbettungen f&uuml;r orthogonale
  65  * Zeichnungen" (in german) by Thorsten Kerkhof (2007) for details.
  66  */
  67 class OGDF_EXPORT EmbedderMinDepthMaxFaceLayers : public EmbedderModule
  68 {
  69 public:
  70         //constructor:
  71         EmbedderMinDepthMaxFaceLayers() { }
  72
  73         /**
  74          * \brief Call embedder algorithm.
  75          * \param G is the original graph. Its adjacency list has to be  changed by the embedder.
  76          * \param adjExternal is an adjacency entry on the external face and has to be set by the embedder.
  77          */
  78         void call(Graph& G, adjEntry& adjExternal);
  79
  80 private:
  81         /**
  82          * \brief Bottom-up-traversal of bcTree computing the values \a m_{cT, bT}
  83          * for all edges (\a cT, \a bT) in the BC-tree. The length of each vertex
  84          * \f$ v \neq c \f$ in \a bT is set to 1 if \f$ v \in M_{bT}\f$ and to 0 otherwise.
  85          *
  86          * \param bT is a block vertex in the BC-tree.
  87          * \param cH is a vertex in the original graph \a G.
  88          * \return Minimum depth of an embedding of \a bT with \a cH on the external
  89          *    face.
  90          */
  91         int md_bottomUpTraversal(const node& bT, const node& cH);
  92
  93         /**
  94          * \brief Top-down-traversal of BC-tree. The minimum depth of the BC-tree-node
  95          * bT is calculated and before calling the function recursively for all
  96          * children of bT in the BC-tree, the nodeLength of the cut-vertex which bT
  97          * and the child have in common is computed. The length of each node is set to
  98          * 1 if it is in M_B and 0 otherwise, except for |M_B| = 1, than it is set to
  99          * 1 if it is in M2 with m2 = \f$\max_{v \in V_B, v != c} m_B(v)\f$ and
 100          * M2 = \f${c \in V_B \ {v} | m_B(c) = m2}\f$.
 101          *
 102          * \param bT is a block vertex in the BC-tree.
 103          */
 104         void md_topDownTraversal(const node& bT);
 105
 106         /**
 107          * \brief Bottom up traversal of BC-tree.
 108          *
 109          * \param bT is the BC-tree node treated in this function call.
 110          * \param cH is the block node which is related to the cut vertex which is
 111          *   parent of bT in BC-tree.
 112          */
 113         int mf_constraintMaxFace(const node& bT, const node& cH);
 114
 115         /**
 116          * \brief Top down traversal of BC-tree.
 117          *
 118          * \param bT is the tree node treated in this function call.
 119          * \param bT_opt is assigned a block node in BC-tree which contains a face that
 120          *   can be expanded to a maximum face.
 121          * \param ell_opt is the size of a maximum face.
 122          */
 123         void mf_maximumFaceRec(const node& bT, node& bT_opt, int& ell_opt);
 124
 125         /**
 126          * \brief Computes the adjacency list for all nodes in a block and calls
 127          * recursively the function for all blocks incident to nodes in bT.
 128          *
 129          * \param bT is the tree node treated in this function call.
 130          */
 131         void embedBlock(const node& bT);
 132
 133         /**
 134          * \brief Computes the adjacency list for all nodes in a block and calls
 135          * recursively the function for all blocks incident to nodes in bT.
 136          *
 137          * \param bT is the tree node treated in this function call.
 138          * \param cT is the parent cut vertex node of bT in the BC-tree. cT is 0 if bT
 139          *   is the root block.
 140          * \param after is the adjacency entry of the cut vertex, after which bT has to
 141          *   be inserted.
 142          */
 143         void embedBlock(const node& bT, const node& cT, ListIterator<adjEntry>& after);
 144
 145 private:
 146         /** the BC-tree of G */
 147         BCTree* pBCTree;
 148
 149         /** an adjacency entry on the external face */
 150         adjEntry* pAdjExternal;
 151
 152         /** saving for each node in the block graph its length */
 153         NodeArray<int> md_nodeLength;
 154
 155         /** an array containing the minimum depth of each block */
 156         NodeArray<int> md_minDepth;
 157
 158         /** an array saving the length for each edge in the BC-tree */
 159         EdgeArray<int> md_m_cB;
 160
 161         /** M_B = \f${cH \in B | m_B(cH) = m_B}\f$ with m_B = \f$\max_{c \in B} m_B(c)\f$
 162          *  and m_B(c) = \f$\max {0} \cup {m_{c, B'} | c \in B', B' \neq B}\f$. */
 163         NodeArray< List<node> > md_M_B;
 164
 165         /** M2 is empty, if |M_B| != 1, otherwise M_B = {cH}
 166          *  M2 = \f${cH' \in V_B \ {v} | m_B(cH') = m2}\f$ with
 167          *  m2 = \f$\max_{vH \in V_B, vH != cH} m_B(vH)\f$. */
 168         NodeArray< List<node> > md_M2;
 169
 170         /** is saving for each node of the block graph its length */
 171         NodeArray<int> mf_nodeLength;
 172
 173         /** is saving for each node of the block graph its cstrLength */
 174         NodeArray<int> mf_cstrLength;
 175
 176         /** an array containing the maximum face size of each block */
 177         NodeArray<int> mf_maxFaceSize;
 178
 179         /** is saving for each node of the block graph its length */
 180         NodeArray<MDMFLengthAttribute> mdmf_nodeLength;
 181
 182         /** is saving for each edge of the block graph its length */
 183         EdgeArray<MDMFLengthAttribute> mdmf_edgeLength;
 184
 185         /** saves for every node of G the new adjacency list */
 186         NodeArray< List<adjEntry> > newOrder;
 187
 188         /** treeNodeTreated saves for all block nodes in the
 189          *  BC-tree if it has already been treated or not. */
 190         NodeArray<bool> treeNodeTreated;
 191 };
 192
 193 } // end namespace ogdf
 194
 195 #endif