org.knime.al.util.noveltydetection.knfst.OneClassKNFST.java Source code

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/*
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 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License, Version 3, as
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 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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 *  along with this program; if not, see <http://www.gnu.org/licenses>.
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 *  Additional permission under GNU GPL version 3 section 7:
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 *  KNIME interoperates with ECLIPSE solely via ECLIPSE's plug-in APIs.
 *  Hence, KNIME and ECLIPSE are both independent programs and are not
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package org.knime.al.util.noveltydetection.knfst;

import java.util.Arrays;

import org.apache.commons.math3.linear.MatrixUtils;
import org.apache.commons.math3.linear.RealMatrix;
import org.apache.commons.math3.linear.RealVector;
import org.knime.al.util.noveltydetection.kernel.KernelCalculator;
import org.knime.core.data.DataRow;
import org.knime.core.node.ExecutionMonitor;

public class OneClassKNFST extends KNFST {

    public OneClassKNFST() {

    }

    public OneClassKNFST(final KernelCalculator kernel, final ExecutionMonitor progMon) throws Exception {
        super(kernel);

        final ExecutionMonitor kernelProgMon = progMon.createSubProgress(0.3);
        final ExecutionMonitor nullspaceProgMon = progMon.createSubProgress(0.7);

        // get number of training samples
        final RealMatrix kernelMatrix = m_kernel.kernelize(kernelProgMon);
        final int n = kernelMatrix.getRowDimension();

        // include dot products of training samples and the origin in feature
        // space (these dot products are always zero!)
        final RealMatrix k = MatrixFunctions.concatVertically(
                MatrixFunctions.concatHorizontally(kernelMatrix,
                        MatrixUtils.createRealMatrix(kernelMatrix.getRowDimension(), 1)),
                MatrixUtils.createRealMatrix(1, kernelMatrix.getColumnDimension() + 1));

        // create one-class labels + a different label for the origin
        final String[] labels = new String[n + 1];
        for (int l = 0; l <= n; l++) {
            labels[l] = (l == n) ? "0" : "1";
        }

        // get model parameters
        nullspaceProgMon.setMessage("Calculating nullspace projection");
        final RealMatrix projection = projection(k, labels);
        nullspaceProgMon.setProgress(1.0, "Finished calculating nullspace projection");
        final int[] indices = new int[n];
        for (int i = 0; i < n; i++) {
            indices[i] = i;
        }
        m_targetPoints = MatrixUtils.createRowRealMatrix(MatrixFunctions
                .columnMeans(k.getSubMatrix(0, n - 1, 0, k.getColumnDimension() - 1).multiply(projection))
                .toArray());
        m_projection = projection.getSubMatrix(0, n - 1, 0, projection.getColumnDimension() - 1);
        m_betweenClassDistances = new double[] { Math.abs(m_targetPoints.getEntry(0, 0)) };
    }

    public OneClassKNFST(final RealMatrix kernelMatrix) throws KNFSTException {
        final int n = kernelMatrix.getRowDimension();

        // include dot products of training samples and the origin in feature
        // space (these dot products are always zero!)
        final RealMatrix k = MatrixFunctions.concatVertically(
                MatrixFunctions.concatHorizontally(kernelMatrix,
                        MatrixUtils.createRealMatrix(kernelMatrix.getRowDimension(), 1)),
                MatrixUtils.createRealMatrix(1, kernelMatrix.getColumnDimension() + 1));

        // create one-class labels + a different label for the origin
        final String[] labels = new String[n + 1];
        for (int l = 0; l <= n; l++) {
            labels[l] = (l == n) ? "0" : "1";
        }

        // get model parameters
        final RealMatrix projection = projection(k, labels);
        final int[] indices = new int[n];
        for (int i = 0; i < n; i++) {
            indices[i] = i;
        }
        m_targetPoints = MatrixUtils.createRowRealMatrix(MatrixFunctions
                .columnMeans(k.getSubMatrix(0, n - 1, 0, k.getColumnDimension() - 1).multiply(projection))
                .toArray());
        m_projection = projection.getSubMatrix(0, n - 1, 0, projection.getColumnDimension() - 1);
        m_betweenClassDistances = new double[] { Math.abs(m_targetPoints.getEntry(0, 0)) };
    }

    @Override
    public NoveltyScores scoreTestData(final RealMatrix kernelMatrix) {
        return score(kernelMatrix);
    }

    @Override
    public NoveltyScores scoreTestData(final DataRow testInstance) {
        final RealMatrix kernelMatrix = m_kernel.kernelize(testInstance);
        return score(kernelMatrix);
    }

    private NoveltyScores score(final RealMatrix kernelMatrix) {
        // projected test samples:
        final RealMatrix projectionVectors = kernelMatrix.transpose().multiply(m_projection);

        // differences to the target value:
        final RealMatrix diff = projectionVectors.subtract(MatrixFunctions
                .ones(kernelMatrix.getColumnDimension(), 1).scalarMultiply(m_targetPoints.getEntry(0, 0)));

        // distances to the target value:
        final RealVector scoresVector = MatrixFunctions
                .sqrt(MatrixFunctions.rowSums(MatrixFunctions.multiplyElementWise(diff, diff)));

        return new NoveltyScores(scoresVector.toArray(), projectionVectors);
    }

    @Override
    public String toString() {
        final int maxLen = 10;
        return "OneClassKNFST [m_kernel=" + m_kernel + ", m_projection=" + m_projection + ", m_targetPoints="
                + m_targetPoints + ", m_betweenClassDistances="
                + (m_betweenClassDistances != null ? Arrays.toString(
                        Arrays.copyOf(m_betweenClassDistances, Math.min(m_betweenClassDistances.length, maxLen)))
                        : null)
                + "]";
    }
}