Example usage for org.apache.commons.math.linear RealMatrix getColumnMatrix

Introduction

In this page you can find the example usage for org.apache.commons.math.linear RealMatrix getColumnMatrix.

Prototype

RealMatrix getColumnMatrix(int column) throws MatrixIndexException;

Source Link

Document

Returns the entries in column number column as a column matrix.

Usage

From source file:PowerMethod.power_method.java

public static power_object power_method(RealMatrix A, RealMatrix v, double epsilon, int N) {
    RealMatrix uInit = v;
    double k = 0;
    double prevK = 0;
    int num = 0;/*  www.j  a v  a2s.  c o m*/
    double accuracy;
    for (int i = N; i > 0; i--) {
        RealMatrix uN = A.multiply(uInit);
        k = uN.getEntry(0, 0);
        for (int j = 0; j < uN.getRowDimension(); j++) {
            uN.setEntry(j, 0, uN.getEntry(j, 0) / k);
        }
        uInit = uN;

        accuracy = Math.abs(k - prevK);
        if (accuracy <= epsilon) {
            break;
        }

        if (accuracy > epsilon && i == 1) {
            return null;
        }

        prevK = k;
        num++;
    }
    double eVal = k;
    RealMatrix eVec = new Array2DRowRealMatrix(uInit.getRowDimension(), uInit.getColumnDimension());

    eVec.setColumnMatrix(0, uInit.getColumnMatrix(0));
    power_object retVal = new power_object(eVal, eVec, num);
    return retVal;
}

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