Exemple #1
0
 public void split() {
   if (m_ilist == null) throw new IllegalStateException("Frozen.  Cannot split.");
   int numLeftChildren = 0;
   boolean[] toLeftChild = new boolean[m_instIndices.length];
   for (int i = 0; i < m_instIndices.length; i++) {
     Instance instance = m_ilist.get(m_instIndices[i]);
     FeatureVector fv = (FeatureVector) instance.getData();
     if (fv.value(m_gainRatio.getMaxValuedIndex()) <= m_gainRatio.getMaxValuedThreshold()) {
       toLeftChild[i] = true;
       numLeftChildren++;
     } else toLeftChild[i] = false;
   }
   logger.info(
       "leftChild.size="
           + numLeftChildren
           + " rightChild.size="
           + (m_instIndices.length - numLeftChildren));
   int[] leftIndices = new int[numLeftChildren];
   int[] rightIndices = new int[m_instIndices.length - numLeftChildren];
   int li = 0, ri = 0;
   for (int i = 0; i < m_instIndices.length; i++) {
     if (toLeftChild[i]) leftIndices[li++] = m_instIndices[i];
     else rightIndices[ri++] = m_instIndices[i];
   }
   m_leftChild = new Node(m_ilist, this, m_minNumInsts, leftIndices);
   m_rightChild = new Node(m_ilist, this, m_minNumInsts, rightIndices);
 }
Exemple #2
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 public Node(InstanceList ilist, Node parent, int minNumInsts, int[] instIndices) {
   if (instIndices == null) {
     instIndices = new int[ilist.size()];
     for (int ii = 0; ii < instIndices.length; ii++) instIndices[ii] = ii;
   }
   m_gainRatio = GainRatio.createGainRatio(ilist, instIndices, minNumInsts);
   m_ilist = ilist;
   m_instIndices = instIndices;
   m_dataDict = m_ilist.getDataAlphabet();
   m_minNumInsts = minNumInsts;
   m_parent = parent;
   m_leftChild = m_rightChild = null;
 }
Exemple #3
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    public double computeCostAndPrune() {
      double costS = getMDL();

      if (isLeaf()) return costS + 1;

      double minCost1 = getLeftChild().computeCostAndPrune();
      double minCost2 = getRightChild().computeCostAndPrune();
      double costSplit = Math.log(m_gainRatio.getNumSplitPointsForBestFeature()) / GainRatio.log2;
      double minCostN = Math.min(costS + 1, costSplit + 1 + minCost1 + minCost2);

      if (Maths.almostEquals(minCostN, costS + 1)) m_leftChild = m_rightChild = null;

      return minCostN;
    }
Exemple #4
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 public Object getSplitFeature() {
   return m_dataDict.lookupObject(m_gainRatio.getMaxValuedIndex());
 }