/*

     This file is part of Combean.

     Combean is free software; you can redistribute it and/or modify

     it under the terms of the GNU General Public License as published by

     the Free Software Foundation; either version 2 of the License, or

     (at your option) any later version.

     Combean is distributed in the hope that it will be useful,

     but WITHOUT ANY WARRANTY; without even the implied warranty of

     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

     GNU General Public License for more details.

     You should have received a copy of the GNU General Public License

     along with Combean; if not, write to the Free Software

     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 */

 /*

  * Created on 07.08.2005

  *

  */

 package net.sourceforge.combean.graph.alg.lp;

 import java.util.Iterator;

 import net.sourceforge.combean.graph.except.UnsupportedGraphProperty;

 import net.sourceforge.combean.graph.prop.statics.GraphPropertyInitializer;

 import net.sourceforge.combean.interfaces.graph.Edge;

 import net.sourceforge.combean.interfaces.graph.Graph;

 import net.sourceforge.combean.interfaces.graph.Node;

 import net.sourceforge.combean.interfaces.graph.prop.GlobalNodesGraphProp;

 import net.sourceforge.combean.interfaces.graph.prop.GlobalNumberedGraphProp;

 import net.sourceforge.combean.interfaces.graph.prop.NeighborhoodGraphProp;

 import net.sourceforge.combean.interfaces.mathprog.linalg.VectorIterator;

 import net.sourceforge.combean.interfaces.mathprog.linalg.VectorOrientation;

 import net.sourceforge.combean.interfaces.mathprog.linalg.VectorValue;

 import net.sourceforge.combean.interfaces.mathprog.lp.model.LPModelColumns;

 import net.sourceforge.combean.interfaces.mathprog.lp.model.LPModelIndex;

 import net.sourceforge.combean.interfaces.mathprog.lp.model.LPSparseVector;

 import net.sourceforge.combean.interfaces.mathprog.lp.model.LPVectorLabel;

 import net.sourceforge.combean.mathprog.linalg.DoubleVectorValue;

 import net.sourceforge.combean.mathprog.lp.model.LPModelIndexImpl;

 import net.sourceforge.combean.mathprog.lp.model.LPVectorLabelImpl;

 import net.sourceforge.combean.util.except.UnsupportedMethodException;

 import org.apache.commons.collections.iterators.SingletonIterator;

 /**

  * Converts a graph into an LP model based on the incidence matrix, i.e.,

  * the rows correspond to the nodes and the columns correspond to the edges.

  * The entry (v,e) is set to -1 if edge e is an outgoing edge of v, set to 1

  * if edge e is an incoming edge of v and zero otherwise. The orientation

  * of the resulting LP component is columnwise.

  * 

  * @author schickin

  *

  */

 public class GraphAsLPModelColumns implements LPModelColumns {

     private NeighborhoodGraphProp neigh = null;

     private GlobalNumberedGraphProp numberedGraph = null;

     private String edgeColumnsOffsetId = "";

     protected String nodeRowsOffsetId = "";

     /**

      * Constructor.

      * 

      * The graph must possess the neighborhood graph property and the

      * global numbered graph property. The edges are considered to be

      * directed.

      * 

      * @param g The graph to be represented by the LP model.

      */

     public GraphAsLPModelColumns(

             String edgeColumnsOffsetId, String nodeRowOffsetId,

             Graph g) {

         super();

         setGraph(g);

         this.edgeColumnsOffsetId = edgeColumnsOffsetId;

         this.nodeRowsOffsetId = nodeRowOffsetId;

     }

     private void setGraph(Graph g) throws UnsupportedGraphProperty {

         GraphPropertyInitializer.setGraphProperties(this, g);

         // access graph property neigh in order to satisfy the compiler

         assert this.neigh != null;

     }

     private class EdgeAsSparseVector implements LPSparseVector {

         private GlobalNodesGraphProp g = null;

         private Edge e = null;

         /**

          * @param e

          */

         public EdgeAsSparseVector(GlobalNodesGraphProp g, Edge e) {

             super();

             this.g = g;

             this.e = e;

         }

         private class EdgeAsVectorIterator

         implements VectorIterator<LPVectorLabel> {

             private EdgeAsSparseVector edgeVec = null;

             private int currNodeNum = 0;

             private LPVectorLabel columnLabel = null;

             /**

              * @param edge

              */

             public EdgeAsVectorIterator(EdgeAsSparseVector edgeVec) {

                 super();

                 this.edgeVec = edgeVec;

                 this.currNodeNum = 0;

                 this.columnLabel = new LPVectorLabelImpl(

                         GraphAsLPModelColumns.this.nodeRowsOffsetId,

                         VectorOrientation.COLUMNWISE);

             }

             /* (non-Javadoc)

              * @see net.sourceforge.combean.interfaces.mathprog.lp.VectorIterator#hasNext()

              */

             public boolean hasNext() {

                  return this.currNodeNum < 2;

             }

             /* (non-Javadoc)

              * @see net.sourceforge.combean.interfaces.mathprog.lp.VectorIterator#next()

              */

             public VectorValue<LPVectorLabel> next() {

                 NeighborhoodGraphProp neigh =

                     (NeighborhoodGraphProp) this.edgeVec.getGraph();

                 GlobalNumberedGraphProp numberedGraph =

                     (GlobalNumberedGraphProp) this.edgeVec.getGraph();

                 Node resultNode = null;

                 double resultVal = 0.0;

                 if (this.currNodeNum == 0) {

                     resultNode = neigh.getFirstNode(this.edgeVec.getEdge());

                     resultVal = -1.0;

                 }

                 else if (this.currNodeNum == 1) {

                     resultNode = neigh.getSecondNode(this.edgeVec.getEdge());

                     resultVal = 1.0;

                 }

                 else {

                     throw new IllegalArgumentException("this code may not be reached");

                 }

                 this.currNodeNum++;

                 return new DoubleVectorValue<LPVectorLabel>(

                         numberedGraph.getNodeNumber(resultNode),

                         resultVal, this.columnLabel);

             }

             /* (non-Javadoc)

              * @see java.util.Iterator#remove()

              */

             public void remove() {

                 throw new UnsupportedMethodException();

             }

         }

         /* (non-Javadoc)

          * @see net.sourceforge.combean.interfaces.mathprog.SparseVector#getDimension()

          */

         public int getDimension() {

              return this.g.getNumNodes();

         }

         /* (non-Javadoc)

          * @see net.sourceforge.combean.interfaces.mathprog.lp.SparseVector#getIterator()

          */

         public VectorIterator<LPVectorLabel> iterator() {

              return new EdgeAsVectorIterator(this);

         }

         /* (non-Javadoc)

          * @see net.sourceforge.combean.interfaces.mathprog.lp.SparseVector#getNumIterations()

          */

         public int getNumIterations() {

              return 2;

         }

         /**

          * @return Returns the edge.

          */

         public final Edge getEdge() {

             return this.e;

         }

         /**

          * @return Returns the graph.

          */

         public final Graph getGraph() {

             return this.g;

         }

         /* (non-Javadoc)

          * @see java.lang.Object#toString()

          */

         public String toString() {

             StringBuffer result = new StringBuffer();

             result.append(getClass().getName());

             result.append("{ edge " + getEdge() + "}");

             return result.toString();

         }

         /* (non-Javadoc)

          * @see net.sourceforge.combean.interfaces.mathprog.linalg.SparseVec#getLabel()

          */

         public Object getLabel() {

              return null;

         }

     }

     /* (non-Javadoc)

      * @see net.sourceforge.combean.interfaces.mathprog.lp.model.LPModelColumns#getColumnVector(int)

      */

     public LPSparseVector getColumnVector(int localColumn) {

         return new EdgeAsSparseVector(this.numberedGraph,

                 this.numberedGraph.getEdge(localColumn));

     }

     /* (non-Javadoc)

      * @see net.sourceforge.combean.interfaces.mathprog.lp.model.LPModelComponent#getNumColumns()

      */

     public int getNumColumns() {

          return this.numberedGraph.getNumEdges();

     }

     /* (non-Javadoc)

      * @see net.sourceforge.combean.interfaces.mathprog.lp.model.LPModelComponent#getNumRows()

      */

     public int getNumRows() {

          return this.numberedGraph.getNumNodes();

     }

     /* (non-Javadoc)

      * @see net.sourceforge.combean.interfaces.mathprog.lp.model.LPModelComponent#getRowModelIndex(int)

      */

     public LPModelIndex getRowModelIndex(int localRow) {

          return new LPModelIndexImpl(localRow, this.nodeRowsOffsetId);

     }

     /* (non-Javadoc)

      * @see net.sourceforge.combean.interfaces.mathprog.lp.model.LPModelComponent#getColumnModelIndex(int)

      */

     public LPModelIndex getColumnModelIndex(int localColumn) {

          return new LPModelIndexImpl(localColumn, this.edgeColumnsOffsetId);

     }

     /* (non-Javadoc)

      * @see net.sourceforge.combean.interfaces.mathprog.lp.model.LPModelComponent#getOrientation()

      */

     public VectorOrientation getOrientation() {

          return VectorOrientation.COLUMNWISE;

     }

     /* (non-Javadoc)

      * @see net.sourceforge.combean.interfaces.mathprog.lp.model.LPModelComponent#getColumnOffsetIds()

      */

     public Iterator getColumnOffsetIds() {

         return new SingletonIterator(this.edgeColumnsOffsetId);

     }

     /* (non-Javadoc)

      * @see net.sourceforge.combean.interfaces.mathprog.lp.model.LPModelComponent#getRowOffsetIds()

      */

     public Iterator getRowOffsetIds() {

         return new SingletonIterator(this.nodeRowsOffsetId);

     }

     /**

      * @param edgeColumnsOffsetId The edgeColumnsOffsetId to set.

      */

     public final void setEdgeColumnsOffsetId(String edgeColumnsOffsetId) {

         this.edgeColumnsOffsetId = edgeColumnsOffsetId;

     }

     /**

      * @return the nodeRowsOffsetId

      */

     public String getNodeRowsOffsetId() {

         return this.nodeRowsOffsetId;

     }

     /**

      * @param nodeRowsOffsetId The nodeRowsOffsetId to set.

      */

     public final void setNodeRowsOffsetId(String nodeRowsOffsetId) {

         this.nodeRowsOffsetId = nodeRowsOffsetId;

     }

 }