Example usage for weka.clusterers SimpleKMeans getClusterStandardDevs

Introduction

In this page you can find the example usage for weka.clusterers SimpleKMeans getClusterStandardDevs.

Prototype

public Instances getClusterStandardDevs() 

Source Link

Document

Gets the standard deviations of the numeric attributes in each cluster.

Usage

From source file:br.ufrn.ia.core.clustering.EMIaProject.java

License:Open Source License

private void EM_Init(Instances inst) throws Exception {
    int i, j, k;/*from  w ww  .  j ava 2  s.  c o  m*/

    // run k means 10 times and choose best solution
    SimpleKMeans bestK = null;
    double bestSqE = Double.MAX_VALUE;
    for (i = 0; i < 10; i++) {
        SimpleKMeans sk = new SimpleKMeans();
        sk.setSeed(m_rr.nextInt());
        sk.setNumClusters(m_num_clusters);
        sk.setDisplayStdDevs(true);
        sk.buildClusterer(inst);
        if (sk.getSquaredError() < bestSqE) {
            bestSqE = sk.getSquaredError();
            bestK = sk;
        }
    }

    // initialize with best k-means solution
    m_num_clusters = bestK.numberOfClusters();
    m_weights = new double[inst.numInstances()][m_num_clusters];
    m_model = new DiscreteEstimator[m_num_clusters][m_num_attribs];
    m_modelNormal = new double[m_num_clusters][m_num_attribs][3];
    m_priors = new double[m_num_clusters];
    Instances centers = bestK.getClusterCentroids();
    Instances stdD = bestK.getClusterStandardDevs();
    double[][][] nominalCounts = bestK.getClusterNominalCounts();
    double[] clusterSizes = bestK.getClusterSizes();

    for (i = 0; i < m_num_clusters; i++) {
        Instance center = centers.instance(i);
        for (j = 0; j < m_num_attribs; j++) {
            if (inst.attribute(j).isNominal()) {
                m_model[i][j] = new DiscreteEstimator(m_theInstances.attribute(j).numValues(), true);
                for (k = 0; k < inst.attribute(j).numValues(); k++) {
                    m_model[i][j].addValue(k, nominalCounts[i][j][k]);
                }
            } else {
                double minStdD = (m_minStdDevPerAtt != null) ? m_minStdDevPerAtt[j] : m_minStdDev;
                double mean = (center.isMissing(j)) ? inst.meanOrMode(j) : center.value(j);
                m_modelNormal[i][j][0] = mean;
                double stdv = (stdD.instance(i).isMissing(j))
                        ? ((m_maxValues[j] - m_minValues[j]) / (2 * m_num_clusters))
                        : stdD.instance(i).value(j);
                if (stdv < minStdD) {
                    stdv = inst.attributeStats(j).numericStats.stdDev;
                    if (Double.isInfinite(stdv)) {
                        stdv = minStdD;
                    }
                    if (stdv < minStdD) {
                        stdv = minStdD;
                    }
                }
                if (stdv <= 0) {
                    stdv = m_minStdDev;
                }

                m_modelNormal[i][j][1] = stdv;
                m_modelNormal[i][j][2] = 1.0;
            }
        }
    }

    for (j = 0; j < m_num_clusters; j++) {
        // m_priors[j] += 1.0;
        m_priors[j] = clusterSizes[j];
    }
    Utils.normalize(m_priors);
}

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