package com.imsl.test.example.math;

import com.imsl.math.*;

/**
 * <p>
 * SparseMatrix Example 1: Computes the matrix product of two sparse
 * matrices.</p>
 *
 * The matrix product of two matrices in sparse format is computed using a
 * method from the SparseMatrix class. The one norm of the result is also
 * computed. The matrix and its norm are printed.
 * <p>
 * See example {@link SuperLUEx1} for an explanation of the sparse format.
 * </p>
 *
 * @see <a href="SparseMatrixEx1.java">Code</a>
 * @see <a href="doc-files/SparseMatrixEx1.out">Output</a>
 */
public class SparseMatrixEx1 {

    public static void main(String args[]) {
        SparseMatrix b = new SparseMatrix(6, 6);
        b.set(0, 0, 10.0);
        b.set(1, 1, 10.0);
        b.set(1, 2, -3.0);
        b.set(1, 3, -1.0);
        b.set(2, 2, 15.0);
        b.set(3, 0, -2.0);
        b.set(3, 3, 10.0);
        b.set(3, 4, -1.0);
        b.set(4, 0, -1.0);
        b.set(4, 3, -5.0);
        b.set(4, 4, 1.0);
        b.set(4, 5, -3.0);
        b.set(5, 0, -1.0);
        b.set(5, 1, -2.0);
        b.set(5, 5, 6.0);

        SparseMatrix c = new SparseMatrix(6, 3);
        c.set(0, 0, 5.0);
        c.set(1, 2, -3.0);
        c.set(2, 0, 1.0);
        c.set(2, 2, 7.0);
        c.set(3, 0, 2.0);
        c.set(4, 1, -5.0);
        c.set(4, 2, 2.0);
        c.set(5, 2, 4.0);

        SparseMatrix A = SparseMatrix.multiply(b, c);

        // Get the one norm of matrix A
        System.out.println("The 1-norm of the matrix is " + A.oneNorm());
        SparseMatrix.SparseArray sa = A.toSparseArray();

        // Print the matrix and its one norm
        System.out.println("row  column  value");
        for (int i = 0; i < sa.numberOfRows; i++) {
            for (int j = 0; j < sa.index[i].length; j++) {
                int jj = sa.index[i][j];
                System.out.println(" " + i + "     " + jj + "     "
                        + sa.values[i][j]);
            }
        }
    }
}