Example usage for weka.core AlgVector AlgVector

Introduction

In this page you can find the example usage for weka.core AlgVector AlgVector.

Prototype

public AlgVector(Instance instance) throws Exception 

Source Link

Document

Constructs a vector using an instance.

Usage

From source file:moa.reduction.bayes.OFSGDAttributeEval.java

License:Open Source License

public void updateEvaluator(Instance inst) throws Exception {

    if (weights == null) {
        weights = new AlgVector(new double[inst.numAttributes() - 1]);
        for (int i = 0; i < weights.numElements(); i++)
            weights.setElement(i, 0);/*from   w  w w . j a va2  s  . c  o m*/
    }

    double[] rawx = Arrays.copyOfRange(inst.toDoubleArray(), 0, inst.numAttributes() - 1);
    AlgVector x = new AlgVector(rawx);
    double pred = weights.dotMultiply(x);

    if (pred * inst.classValue() <= 1) {
        x.scalarMultiply(eta * inst.classValue());
        weights = weights.add(x);
        weights.scalarMultiply(Math.min(1.0, 1 / (Math.sqrt(lambda) * weights.norm())));

        int counts = 0;
        Pair[] array = new Pair[weights.numElements()];
        for (int i = 0; i < weights.numElements(); i++) {
            array[i] = new Pair(i, weights.getElement(i));
            if (weights.getElement(i) != 0)
                counts++;
        }

        // Truncate
        if (counts > numFeatures) {
            Arrays.sort(array);
            for (int i = numFeatures + 1; i < array.length; i++)
                weights.setElement(array[i].index, 0);
        }
    }
    updated = true;
}

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