@Override
  public Model learn(ExampleSet exampleSet) throws OperatorException {
    DistanceMeasure measure = DistanceMeasures.createMeasure(this);
    measure.init(exampleSet);
    GeometricDataCollection<RegressionData> data = new LinearList<RegressionData>(measure);

    // check if weights should be used
    boolean useWeights = getParameterAsBoolean(PARAMETER_USE_EXAMPLE_WEIGHTS);
    // check if robust estimate should be performed: Then calculate weights and use it anyway
    if (getParameterAsBoolean(PARAMETER_USE_ROBUST_ESTIMATION)) {
      useWeights = true;
      LocalPolynomialExampleWeightingOperator weightingOperator;
      try {
        weightingOperator =
            OperatorService.createOperator(LocalPolynomialExampleWeightingOperator.class);
        exampleSet = weightingOperator.doWork((ExampleSet) exampleSet.clone(), this);
      } catch (OperatorCreationException e) {
        throw new UserError(this, 904, "LocalPolynomialExampleWeighting", e.getMessage());
      }
    }

    Attributes attributes = exampleSet.getAttributes();
    Attribute label = attributes.getLabel();
    Attribute weightAttribute = attributes.getWeight();
    for (Example example : exampleSet) {
      double[] values = new double[attributes.size()];
      double labelValue = example.getValue(label);
      double weight = 1d;
      if (weightAttribute != null && useWeights) {
        weight = example.getValue(weightAttribute);
      }

      // filter out examples without influence
      if (weight > 0d) {
        // copying example values
        int i = 0;
        for (Attribute attribute : attributes) {
          values[i] = example.getValue(attribute);
          i++;
        }

        // inserting into geometric data collection
        data.add(values, new RegressionData(values, labelValue, weight));
      }
    }
    return new LocalPolynomialRegressionModel(
        exampleSet,
        data,
        Neighborhoods.createNeighborhood(this),
        SmoothingKernels.createKernel(this),
        getParameterAsInt(PARAMETER_DEGREE),
        getParameterAsDouble(PARAMETER_RIDGE));
  }
Ejemplo n.º 2
0
  @Override
  public ClusterModel generateClusterModel(ExampleSet exampleSet) throws OperatorException {
    int k = getParameterAsInt(PARAMETER_K);
    int maxOptimizationSteps = getParameterAsInt(PARAMETER_MAX_OPTIMIZATION_STEPS);
    boolean useExampleWeights = getParameterAsBoolean(PARAMETER_USE_WEIGHTS);
    Kernel kernel = Kernel.createKernel(this);

    // init operator progress
    getProgress().setTotal(maxOptimizationSteps);

    // checking and creating ids if necessary
    Tools.checkAndCreateIds(exampleSet);

    // additional checks
    Tools.onlyNonMissingValues(exampleSet, getOperatorClassName(), this, new String[0]);

    if (exampleSet.size() < k) {
      throw new UserError(this, 142, k);
    }

    // extracting attribute names
    Attributes attributes = exampleSet.getAttributes();
    ArrayList<String> attributeNames = new ArrayList<String>(attributes.size());
    for (Attribute attribute : attributes) {
      attributeNames.add(attribute.getName());
    }
    Attribute weightAttribute = attributes.getWeight();

    RandomGenerator generator = RandomGenerator.getRandomGenerator(this);

    ClusterModel model =
        new ClusterModel(
            exampleSet,
            k,
            getParameterAsBoolean(RMAbstractClusterer.PARAMETER_ADD_AS_LABEL),
            getParameterAsBoolean(RMAbstractClusterer.PARAMETER_REMOVE_UNLABELED));
    // init centroids
    int[] clusterAssignments = new int[exampleSet.size()];

    for (int i = 0; i < exampleSet.size(); i++) {
      clusterAssignments[i] = generator.nextIntInRange(0, k);
    }

    // run optimization steps
    boolean stable = false;
    for (int step = 0; step < maxOptimizationSteps && !stable; step++) {
      // calculating cluster kernel properties
      double[] clusterWeights = new double[k];
      double[] clusterKernelCorrection = new double[k];
      int i = 0;
      for (Example firstExample : exampleSet) {
        double firstExampleWeight = useExampleWeights ? firstExample.getValue(weightAttribute) : 1d;
        double[] firstExampleValues = getAsDoubleArray(firstExample, attributes);
        clusterWeights[clusterAssignments[i]] += firstExampleWeight;
        int j = 0;
        for (Example secondExample : exampleSet) {
          if (clusterAssignments[i] == clusterAssignments[j]) {
            double secondExampleWeight =
                useExampleWeights ? secondExample.getValue(weightAttribute) : 1d;
            clusterKernelCorrection[clusterAssignments[i]] +=
                firstExampleWeight
                    * secondExampleWeight
                    * kernel.calculateDistance(
                        firstExampleValues, getAsDoubleArray(secondExample, attributes));
          }
          j++;
        }
        i++;
      }
      for (int z = 0; z < k; z++) {
        clusterKernelCorrection[z] /= clusterWeights[z] * clusterWeights[z];
      }

      // assign examples to new centroids
      int[] newClusterAssignments = new int[exampleSet.size()];
      i = 0;
      for (Example example : exampleSet) {
        double[] exampleValues = getAsDoubleArray(example, attributes);
        double exampleKernelValue = kernel.calculateDistance(exampleValues, exampleValues);
        double nearestDistance = Double.POSITIVE_INFINITY;
        int nearestIndex = 0;
        for (int clusterIndex = 0; clusterIndex < k; clusterIndex++) {
          double distance = 0;
          // iterating over all examples in cluster to get kernel distance
          int j = 0;
          for (Example clusterExample : exampleSet) {
            if (clusterAssignments[j] == clusterIndex) {
              distance +=
                  (useExampleWeights ? clusterExample.getValue(weightAttribute) : 1d)
                      * kernel.calculateDistance(
                          getAsDoubleArray(clusterExample, attributes), exampleValues);
            }
            j++;
          }
          distance *= -2d / clusterWeights[clusterIndex];
          // copy in outer loop
          distance += exampleKernelValue;
          distance += clusterKernelCorrection[clusterIndex];
          if (distance < nearestDistance) {
            nearestDistance = distance;
            nearestIndex = clusterIndex;
          }
        }
        newClusterAssignments[i] = nearestIndex;
        i++;
      }

      // finishing assignment
      stable = true;
      for (int j = 0; j < exampleSet.size() && stable; j++) {
        stable &= newClusterAssignments[j] == clusterAssignments[j];
      }
      clusterAssignments = newClusterAssignments;

      // trigger operator progress
      getProgress().step();
    }

    // setting last clustering into model
    model.setClusterAssignments(clusterAssignments, exampleSet);

    getProgress().complete();

    if (addsClusterAttribute()) {
      Attribute cluster = AttributeFactory.createAttribute("cluster", Ontology.NOMINAL);
      exampleSet.getExampleTable().addAttribute(cluster);
      exampleSet.getAttributes().setCluster(cluster);
      int i = 0;
      for (Example example : exampleSet) {
        example.setValue(cluster, "cluster_" + clusterAssignments[i]);
        i++;
      }
    }
    return model;
  }