public void write(DataOutput out) throws IOException {
   score.write(out);
   vertices.write(out);
 }
 public boolean equals(Object o) {
   return score.equals(((SemiClusterWritable) o).score)
       && vertices.equals(((SemiClusterWritable) o).vertices);
 }
 // /////////////////////////////////////
 // Writable
 // /////////////////////////////////////
 public void readFields(DataInput in) throws IOException {
   score.readFields(in);
   vertices.readFields(in);
 }