Example usage for weka.attributeSelection PrincipalComponents getEigenValues

Introduction

In this page you can find the example usage for weka.attributeSelection PrincipalComponents getEigenValues.

Prototype

public double[] getEigenValues() 

Source Link

Document

Return the eigenvalues corresponding to the eigenvectors

Usage

From source file:PCADetector.java

License:Apache License

public boolean runPCA(ArrayList<Double> newData, int slidewdSz, double cAlpha, int nAttrs) {
    try {//w w w.j a  va  2s .c  om
        if (m_nDims == 0) {
            m_nDims = nAttrs;
            for (int i = 0; i < this.m_nDims; i++) {
                m_oriDataMatrix.add(new ArrayList<Double>()); // one list for each attribute
            }
        }
        verifyData(newData);
        this.c_alpha = cAlpha;
        if (false == prepareData(newData, slidewdSz))
            return false;
        Instances oriDataInsts = getInstances();
        if (oriDataInsts != null) {
            // standardization + PCA covariance matrix
            m_scaledInstances = new Instances(oriDataInsts);
            Standardize filter = new Standardize();

            filter.setInputFormat(m_scaledInstances);
            m_scaledInstances = Standardize.useFilter(m_scaledInstances, filter); // standardization

            PrincipalComponents PCA = new PrincipalComponents();
            PCA.setVarianceCovered(1.0); // means 100%
            PCA.setMaximumAttributeNames(-1);
            PCA.setCenterData(true);
            Ranker ranker = new Ranker();
            AttributeSelection selector = new AttributeSelection();
            selector.setSearch(ranker);
            selector.setEvaluator(PCA);
            selector.SelectAttributes(m_scaledInstances);
            //                Instances transformedData = selector.reduceDimensionality(m_scaledInstances);

            // get sorted eigens
            double[] eigenValues = PCA.getEigenValues();
            // eigenVectors[i][j]  i: rows; j: cols
            double[][] eigenVectors = PCA.getUnsortedEigenVectors();
            Sort(eigenValues, eigenVectors);
            setEigens(eigenValues);

            // get residual start dimension
            int residualStartDimension = -1;
            double sum = 0;
            double major = 0;
            for (int ss = 0; ss < eigenValues.length; ss++) {
                sum += eigenValues[ss];
            }
            for (int ss = 0; ss < eigenValues.length; ss++) {
                major += eigenValues[ss];
                if ((residualStartDimension < 0) && (major / sum > 0.95)) {
                    residualStartDimension = ss + 1;
                    break;
                }
            }
            //            System.out.println("residualStartDim: "+residualStartDimension);
            m_threshold = computeThreshold(eigenValues, residualStartDimension);

            // check new data abnormal or not
            boolean bAbnormal = checkSPE(eigenVectors, residualStartDimension, newData);
            computeProjPCs(eigenVectors, residualStartDimension, newData); // only for demo

            if (bAbnormal) { // anomaly, now to diagnosis
                // check original space using all the lists
                diagnosis(eigenVectors, residualStartDimension, newData);
            }

        }

    } catch (Exception exc) {
    }
    return true;
}

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From source file:org.knowrob.knowrob_sim_games.MongoSimGames.java

License:Open Source License

/**
 * Return the roundness from the PCA, using the eigenvalues
 *//*w w  w .  ja  va  2s .c  om*/
public double GetPCARoundness(PrincipalComponents pca) {

    // get the eigenvalues of the pca
    double[] eigenvalues = pca.getEigenValues();

    // get the nr of eigenvalues
    int length = eigenvalues.length;

    // return the roundness by dividing the before last value with the last
    // (the last [length-1] being the greatest)
    return eigenvalues[length - 2] / eigenvalues[length - 1];
}

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