Example usage for org.apache.mahout.math.function Mult div

Introduction

In this page you can find the example usage for org.apache.mahout.math.function Mult div.

Prototype

public static Mult div(double constant) 

Source Link

Document

a / constant.

Usage

From source file:org.carrot2.matrix.factorization.KMeansMatrixFactorization.java

License:Open Source License

public void compute() {
    int n = A.columns();

    // Distances to centroids
    DoubleMatrix2D D = new DenseDoubleMatrix2D(k, n);

    // Object-cluster assignments
    V = new DenseDoubleMatrix2D(n, k);

    // Initialize the centroids with some document vectors
    U = new DenseDoubleMatrix2D(A.rows(), k);
    U.assign(A.viewPart(0, 0, A.rows(), k));

    int[] minIndices = new int[D.columns()];
    double[] minValues = new double[D.columns()];

    for (iterationsCompleted = 0; iterationsCompleted < maxIterations; iterationsCompleted++) {
        // Calculate cosine distances
        U.zMult(A, D, 1, 0, true, false);

        V.assign(0);/*from  w  w w. ja  va  2 s.  c  om*/
        U.assign(0);

        // For each object
        MatrixUtils.maxInColumns(D, minIndices, minValues);
        for (int i = 0; i < minIndices.length; i++) {
            V.setQuick(i, minIndices[i], 1);
        }

        // Update centroids
        for (int c = 0; c < V.columns(); c++) {
            // Sum
            int count = 0;
            for (int d = 0; d < V.rows(); d++) {
                if (V.getQuick(d, c) != 0) {
                    count++;
                    U.viewColumn(c).assign(A.viewColumn(d), Functions.PLUS);
                }
            }

            // Divide
            U.viewColumn(c).assign(Mult.div(count));
            MatrixUtils.normalizeColumnL2(U, null);
        }

    }
}

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