Example usage for org.apache.mahout.math.function Functions SQUARE

Introduction

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

Prototype

DoubleFunction SQUARE

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Document

Function that returns a * a.

Usage

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

License:Open Source License

/**
 * Orders U and V matrices according to the 'activity' of base vectors.
 *//*from  ww  w  . j  av  a  2 s  . c om*/
protected void order() {
    DoubleMatrix2D VT = V.viewDice();
    aggregates = new double[VT.rows()];

    for (int i = 0; i < aggregates.length; i++) {
        aggregates[i] = VT.viewRow(i).aggregate(Functions.PLUS, Functions.SQUARE);
    }

    final IndirectComparator.DescendingDoubleComparator comparator = new IndirectComparator.DescendingDoubleComparator(
            aggregates);
    V = MatrixUtils.sortedRowsView(VT, comparator).viewDice();
    U = MatrixUtils.sortedRowsView(U.viewDice(), comparator).viewDice();
}

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From source file:org.carrot2.matrix.MatrixUtils.java

License:Open Source License

/**
 * Calculates the Frobenius norm of a matrix.
 * // w ww  . ja  v  a  2 s.c om
 * @see <a href="http://en.wikipedia.org/wiki/Matrix_norm#Frobenius_norm">Frobenius
 *      norm</a>
 */
public static double frobeniusNorm(DoubleMatrix2D matrix) {
    return Math.sqrt(matrix.aggregate(Functions.PLUS, Functions.SQUARE));
}

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