indices[num] = instance.index(j);
    num++;
  }
      } 
      if (num == instance.numValues()) {
  inst = new SparseInstance(instance.weight(), vals, indices,
                                  instance.numAttributes());
      } else {
  double []tempVals = new double[num];
  int []tempInd = new int[num];
  System.arraycopy(vals, 0, tempVals, 0, num);
  System.arraycopy(indices, 0, tempInd, 0, num);
  inst = new SparseInstance(instance.weight(), tempVals, tempInd,
                                  instance.numAttributes());
      }
    } else {
      double []vals = new double[getInputFormat().numAttributes()];
      for (int j = 0; j < instance.numAttributes(); j++) {