package com.imsl.test.example.math;

import com.imsl.math.*;

/**
 * <p>
 * Computes the SVD factorization of a matrix.</p>
 * The singular value decomposition of a matrix is performed. The rank of the
 * matrix is also computed.
 *
 * @see <a href="SVDEx1.java">Code</a>
 * @see <a href="doc-files/SVDEx1.out">Output</a>
 */
public class SVDEx1 {

    public static void main(String args[]) throws SVD.DidNotConvergeException {
        double a[][] = {
            {1, 2, 1, 4},
            {3, 2, 1, 3},
            {4, 3, 1, 4},
            {2, 1, 3, 1},
            {1, 5, 2, 2},
            {1, 2, 2, 3}
        };

        // Compute the SVD factorization of A
        SVD svd = new SVD(a);

        // Print U, S and V.
        new PrintMatrix("U").print(svd.getU());
        new PrintMatrix("S").print(svd.getS());
        new PrintMatrix("V").print(svd.getV());

        // Find the rank of A.
        int rank = svd.getRank();
        System.out.println("rank = " + rank);
    }
}