push(new SparseInstance(instance.weight(), vals));
inst = new SparseInstance(instance.weight(), vals);
  public boolean input(Instance instance) throws Exception {    if (getInputFormat() == null) {      throw new Exception("No input instance format defined");    }    if (m_NewBatch) {      resetQueue();      m_NewBatch = false;    }    Instances outputFormat = outputFormatPeek();    double[] vals = new double[outputFormat.numAttributes()];    boolean inRange = false;    double lastVal = Instance.missingValue();    int i, j;    for(i = 0, j = 0; j < outputFormat.numAttributes(); i++) {      if (m_DeltaCols.isInRange(i)) {	if (inRange) {	  if (Instance.isMissingValue(lastVal) || instance.isMissing(i)) {	    vals[j++] = Instance.missingValue();	  } else {	    vals[j++] = instance.value(i) - lastVal;	  }	} else {	  inRange = true;	}	lastVal = instance.value(i);      } else {	vals[j++] = instance.value(i);      }    }    if (instance instanceof SparseInstance) {      push(new SparseInstance(instance.weight(), vals));    } else {      push(new Instance(instance.weight(), vals));    }    return true;  }