Java, zmatek v tridach a instanci atd.. – Java – Fórum – Programujte.com

Ahoj,
mam dost zmatek v tech ruznych vychytavkach objektoveho programovani a momentalne jsem se v jednom projektu zabrzdil na jedne veci..

package maticeproject2009;



final public class Matrix {

    private final int M;             // number of rows

    private final int N;             // number of columns

    private final double[][] data;   // M-by-N array



    // create M-by-N matrix of 0's

    public Matrix(int M, int N) {

        this.M = M;

        this.N = N;

        data = new double[M][N];

    }



    // create matrix based on 2d array

    public Matrix(double[][] data) {

        M = data.length;

        N = data[0].length;

        this.data = new double[M][N];

        for (int i = 0; i < M; i++)

            for (int j = 0; j < N; j++)

                    this.data[i][j] = data[i][j];

    }



    // copy constructor

    private Matrix(Matrix A) { this(A.data); }



    // print matrix to standard output

    public void show() {

        for (int i = 0; i < M; i++) {

            for (int j = 0; j < N; j++)

                System.out.printf("%9.4f ", data[i][j]);

            System.out.println();

        }

    }

    

    public Matrix gaussian() {

        // create copies of the data

        Matrix A = new Matrix(this);



        // Gaussian elimination with partial pivoting

        for (int i = 0; i < N; i++) {



            // find pivot row and swap

            int max = i;

            for (int j = i + 1; j < N; j++)

                if (Math.abs(A.data[j][i]) > Math.abs(A.data[max][i]))

                    max = j;

            A.swap(i, max);



            // pivot within A

            for (int j = i + 1; j < N; j++) {

                double m = A.data[j][i] / A.data[i][i];

                for (int k = i+1; k < N; k++) {

                    A.data[j][k] -= A.data[i][k] * m;

                }

                A.data[j][i] = 0.0;

            }

        }

        return A;

    }



    // swap rows i and j

    private void swap(int i, int j) {

        double[] temp = data[i];

        data[i] = data[j];

        data[j] = temp;

    }



    // test client

    public static void main(String[] args) {

        double[][] d = { { 8, -1, -2, 0 }, { -1, 7, -1, 10 }, { -2, -1, 9, 23} };

        Matrix A = new Matrix(d);

        A.show();

        System.out.println();



        A.gaussian();

        System.out.println("Uprava na schodovy tvar:");

        A.show();

    }

}

if (Math.abs(A.data[j][i]) > Math.abs(A.data[max][i]))

To nieje o objektovo orientovanom programovani, ale o tom ze nechapes algoritmu... Nejdem to teraz presne riesit ale zrejme si chcel spravit Gaussovu eliminacnu metodu...

Problem je v tom ze tam mas vela chyb, resp. casto menis indexy jeden za druhy a celkovo ten algoritmus nedava zmysel...