Exemple #1
0
  /**
   * This is the method to call for assigning labels and node vectors to the Tree. After calling
   * this, each of the non-leaf nodes will have the node vector and the predictions of their classes
   * assigned to that subtree's node.
   */
  public void forwardPropagateTree(Tree tree) {
    INDArray nodeVector;
    INDArray classification;

    if (tree.isLeaf()) {
      // We do nothing for the leaves.  The preterminals will
      // calculate the classification for this word/tag.  In fact, the
      // recursion should not have gotten here (unless there are
      // degenerate trees of just one leaf)
      throw new AssertionError("We should not have reached leaves in forwardPropagate");
    } else if (tree.isPreTerminal()) {
      classification = getUnaryClassification(tree.label());
      String word = tree.children().get(0).value();
      INDArray wordVector = getFeatureVector(word);
      if (wordVector == null) {
        wordVector = featureVectors.vector(Word2Vec.UNK);
      }

      nodeVector =
          Nd4j.getExecutioner()
              .execAndReturn(Nd4j.getOpFactory().createTransform(activationFunction, wordVector));
    } else if (tree.children().size() == 1) {
      throw new AssertionError(
          "Non-preterminal nodes of size 1 should have already been collapsed");
    } else if (tree.children().size() == 2) {
      Tree left = tree.firstChild(), right = tree.lastChild();
      forwardPropagateTree(left);
      forwardPropagateTree(right);

      String leftCategory = tree.children().get(0).label();
      String rightCategory = tree.children().get(1).label();
      INDArray W = getBinaryTransform(leftCategory, rightCategory);
      classification = getBinaryClassification(leftCategory, rightCategory);

      INDArray leftVector = tree.children().get(0).vector();
      INDArray rightVector = tree.children().get(1).vector();

      INDArray childrenVector = Nd4j.appendBias(leftVector, rightVector);

      if (useDoubleTensors) {
        INDArray doubleT = getBinaryINDArray(leftCategory, rightCategory);
        INDArray INDArrayIn = Nd4j.concat(0, leftVector, rightVector);
        INDArray INDArrayOut = Nd4j.bilinearProducts(doubleT, INDArrayIn);
        nodeVector =
            Nd4j.getExecutioner()
                .execAndReturn(
                    Nd4j.getOpFactory()
                        .createTransform(
                            activationFunction, W.mmul(childrenVector).addi(INDArrayOut)));

      } else
        nodeVector =
            Nd4j.getExecutioner()
                .execAndReturn(
                    Nd4j.getOpFactory()
                        .createTransform(activationFunction, W.mmul(childrenVector)));

    } else {
      throw new AssertionError("Tree not correctly binarized");
    }

    INDArray inputWithBias = Nd4j.appendBias(nodeVector);
    if (inputWithBias.rows() != classification.columns()) inputWithBias = inputWithBias.transpose();
    INDArray preAct = classification.mmul(inputWithBias);
    INDArray predictions =
        Nd4j.getExecutioner()
            .execAndReturn(Nd4j.getOpFactory().createTransform(outputActivation, preAct));

    tree.setPrediction(predictions);
    tree.setVector(nodeVector);
  }