AdjacencyMatrix.java

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package aud.graph;
 
import java.util.Iterator;
import java.util.Map;
import java.util.TreeMap;
import aud.graph.matrix.Coordinate;
import aud.graph.matrix.SparseMatrix;
 
public class AdjacencyMatrix<Edge>
  extends SparseMatrix<Edge> implements Iterable<Edge> {
 
 
  public AdjacencyMatrix(boolean symmetric) {
    super(symmetric);
  }
 
  public void clearColumnAndRow(int idx) {
    int[] ri=getColumnRowIndices(idx);
    for (int k=0;k<ri.length;++k)
      set(ri[k],idx,null);
 
    if (!isSymmetricMatrix()) {
      int[] ci=getRowColumnIndices(idx);
       for (int k=0;k<ci.length;++k)
         set(idx,ci[k],null);
    }
  }
 
  @Override public Iterator<Edge> iterator() {
    // inefficient!
    if (isSymmetricMatrix()) {
      // copy and remove_if
      TreeMap<Coordinate,Edge> m=new TreeMap<Coordinate,Edge>(mat_);
      for (Iterator<Map.Entry<Coordinate,Edge>> ii=m.entrySet().iterator();
           ii.hasNext();) {
        Map.Entry<Coordinate,Edge> entry=ii.next();
        Coordinate c=entry.getKey();
        if (c.i>c.j)
          ii.remove();
      }
      return m.values().iterator();
    }
    else
      return mat_.values().iterator();
  }
}