/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOUSE. See the GNU
 * General Public License for more details.
 *
 * You should have recieved a copy of the GNU General Public License
 * along with this program; if not write to the Free Software
 * Foundation, inc., 59 Temple Place, Suite 330, Boston MA 02111-1307
 * USA
 */

package Jama;


import Jama.util.*;

import uka.transport.*;
import uka.patch.*;

import java.io.BufferedReader;
import java.io.PrintWriter;
import java.io.StreamTokenizer;

import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.text.NumberFormat;

import java.util.Locale;

import uka.util.Printable;
import uka.util.ToString;


// **********

/**
 * Jama = Java Matrix class.
 * 
 * <P>
 * The Java Matrix Class provides the fundamental operations of numerical
 * linear algebra.  Various constructors create Matrices from two dimensional
 * arrays of double precision floating point numbers.  Various "gets" and
 * "sets" provide access to submatrices and matrix elements.  Several methods
 * implement basic matrix arithmetic, including matrix addition and
 * multiplication, matrix norms, and element-by-element array operations.
 * Methods for reading and printing matrices are also included.  All the
 * operations in this version of the Matrix Class involve real matrices.
 * Complex matrices may be handled in a future version.
 * </p>
 * 
 * <P>
 * Five fundamental matrix decompositions, which consist of pairs or triples of
 * matrices, permutation vectors, and the like, produce results in five
 * decomposition classes.  These decompositions are accessed by the Matrix
 * class to compute solutions of simultaneous linear equations, determinants,
 * inverses and other matrix functions.  The five decompositions are:
 * </p>
 * 
 * <P>
 * 
 * <UL>
 * <li>
 * Cholesky Decomposition of symmetric, positive definite matrices.
 * </li>
 * <li>
 * LU Decomposition of rectangular matrices.
 * </li>
 * <li>
 * QR Decomposition of rectangular matrices.
 * </li>
 * <li>
 * Singular Value Decomposition of rectangular matrices.
 * </li>
 * <li>
 * Eigenvalue Decomposition of both symmetric and nonsymmetric square matrices.
 * </li>
 * </ul>
 * 
 * 
 * <DL>
 * <dt>
 * <B>Example of use:</B>
 * </dt>
 * <dd>
 * Solve a linear system A x = b and compute the residual norm, ||b - A x||.
 * 
 * <P>
 * <PRE>
 *  double[][] vals = {{1.,2.,3},{4.,5.,6.},{7.,8.,10.}};
 *  Matrix A = new Matrix(vals);
 *  Matrix b = Matrix.random(3,1);
 *  Matrix x = A.solve(b);
 *  Matrix r = A.times(x).minus(b);
 *  double rnorm = r.normInf();
 *  </PRE>
 * </p>
 * </dd>
 * </dl>
 * </p>
 *
 * @author The MathWorks, Inc. and the National Institute of Standards and
 *         Technology.
 * @version 5 August 1998
 */
public class Matrix implements Printable, Cloneable, Transportable, Patchable, java.io.Serializable {
    /* ------------------------
       Class variables
     * ------------------------ */

    /**
     * Array for internal storage of elements.
     *
     * @serial internal array storage.
     */
    protected double[][] A;

    /**
     * Row and column dimensions.
     *
     * @serial column dimension.
     */
    protected int m;

    /**
     * Row and column dimensions.
     *
     * @serial column dimension.
     */
    protected int n;

    /* ------------------------
       Constructors
     * ------------------------ */

    /**
     * Construct an m-by-n matrix of zeros.
     *
     * @param m Number of rows.
     * @param n Number of colums.
     */
    public Matrix(int m, int n) {
        this.m = m;
        this.n = n;
        A = new double[m][n];
        //System.out.println("---Matrix---(" + this.getClass().getName() + "@" + Integer.toHexString(this.hashCode()) + ")\n" +
        //                   "            Array: " + A.getClass().getName() + "@" + Integer.toHexString(A.hashCode()));
    }

    /**
     * Construct an m-by-n constant matrix.
     *
     * @param m Number of rows.
     * @param n Number of colums.
     * @param s Fill the matrix with this scalar value.
     */
    public Matrix(int m, int n, double s) {
        this.m = m;
        this.n = n;
        A = new double[m][n];

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                A[i][j] = s;
            }
        }
    }

    /**
     * Construct a matrix from a one-dimensional packed array
     *
     * @param vals One-dimensional array of doubles, packed by columns (ala
     *        Fortran).
     * @param m Number of rows.
     *
     * @exception IllegalArgumentException Array length must be a multiple of
     *            m.
     */
    public Matrix(double[] vals, int m) {
        this.m = m;
        n = ((m != 0) ? (vals.length / m) : 0);

        if ((m * n) != vals.length) {
            throw new IllegalArgumentException(
                "Array length must be a multiple of m."
            );
        }

        A = new double[m][n];

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                A[i][j] = vals[i + (j * m)];
            }
        }
    }

    /**
     * Construct a matrix from a 2-D array.
     *
     * @param A Two-dimensional array of doubles.
     *
     * @exception IllegalArgumentException All rows must have the same length
     *
     * @see #constructWithCopy
     */
    public Matrix(double[][] A) {
        m = A.length;
        n = A[0].length;

        for (int i = 0; i < m; i++) {
            if (A[i].length != n) {
                throw new IllegalArgumentException(
                    "All rows must have the same length."
                );
            }
        }

        this.A = A;
    }

    /**
     * Construct a matrix from a 2-D array.
     *
     * @param A Two-dimensional array of floats.
     *
     * @exception IllegalArgumentException All rows must have the same length
     *
     * @see #constructWithCopy
     */
    public Matrix(float[][] A) {
        m = A.length;
        n = A[0].length;

        for (int i = 0; i < m; i++) {
            if (A[i].length != n) {
                throw new IllegalArgumentException(
                    "All rows must have the same length."
                );
            }
        }

        this.A = new double[m][n];
        
        for(int i=0; i<m; i++)
            for(int j=0; j<n; j++)
                this.A[i][j] = (double)A[i][j];
    }
    
    
    /**
     * Construct a matrix quickly without checking arguments.
     *
     * @param A Two-dimensional array of doubles.
     * @param m Number of rows.
     * @param n Number of colums.
     */
    public Matrix(double[][] A, int m, int n) {
        this.A = A;
        this.m = m;
        this.n = n;
    }

    /**
     * Element-by-element left division, C = A.\B
     *
     * @param B another matrix
     *
     * @return A.\B
     */
    public Matrix arrayLeftDivide(Matrix B) {
        checkMatrixDimensions(B);

        Matrix X = new Matrix(m, n);
        double[][] C = X.getArray();

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                C[i][j] = B.A[i][j] / A[i][j];
            }
        }

        return X;
    }

    /**
     * Element-by-element left division in place, A = A.\B
     *
     * @param B another matrix
     *
     * @return A.\B
     */
    public Matrix arrayLeftDivideEquals(Matrix B) {
        checkMatrixDimensions(B);

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                A[i][j] = B.A[i][j] / A[i][j];
            }
        }

        return this;
    }

    /**
     * Element-by-element right division, C = A./B
     *
     * @param B another matrix
     *
     * @return A./B
     */
    public Matrix arrayRightDivide(Matrix B) {
        checkMatrixDimensions(B);

        Matrix X = new Matrix(m, n);
        double[][] C = X.getArray();

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                C[i][j] = A[i][j] / B.A[i][j];
            }
        }

        return X;
    }

    /**
     * Element-by-element right division in place, A = A./B
     *
     * @param B another matrix
     *
     * @return A./B
     */
    public Matrix arrayRightDivideEquals(Matrix B) {
        checkMatrixDimensions(B);

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                A[i][j] = A[i][j] / B.A[i][j];
            }
        }

        return this;
    }

    /**
     * Element-by-element multiplication, C = A.B
     *
     * @param B another matrix
     *
     * @return A.B
     */
    public Matrix arrayTimes(Matrix B) {
        checkMatrixDimensions(B);

        Matrix X = new Matrix(m, n);
        double[][] C = X.getArray();

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                C[i][j] = A[i][j] * B.A[i][j];
            }
        }

        return X;
    }

    /**
     * Element-by-element multiplication in place, A = A.B
     *
     * @param B another matrix
     *
     * @return A.B
     */
    public Matrix arrayTimesEquals(Matrix B) {
        checkMatrixDimensions(B);

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                A[i][j] = A[i][j] * B.A[i][j];
            }
        }

        return this;
    }

    /* ------------------------
       Private Methods
     * ------------------------ */

    /**
     * Check if size(A) == size(B)
     */
    private void checkMatrixDimensions(Matrix B) {
        if ((B.m != m) || (B.n != n)) {
            throw new IllegalArgumentException("Matrix dimensions must agree.");
        }
    }

    /**
     * Cholesky Decomposition
     *
     * @return CholeskyDecomposition
     *
     * @see CholeskyDecomposition
     */
    public CholeskyDecomposition chol() {
        return new CholeskyDecomposition(this);
    }

    /**
     * Matrix condition (2 norm)
     *
     * @return ratio of largest to smallest singular value.
     */
    public double cond() {
        return new SingularValueDecomposition(this).cond();
    }

    /* ------------------------
       Public Methods
     * ------------------------ */

    /**
     * Construct a matrix from a copy of a 2-D array.
     *
     * @param A Two-dimensional array of doubles.
     *
     * @exception IllegalArgumentException All rows must have the same length
     */
    public static Matrix constructWithCopy(double[][] A) {
        int m = A.length;
        int n = A[0].length;
        Matrix X = new Matrix(m, n);
        double[][] C = X.getArray();

        for (int i = 0; i < m; i++) {
            if (A[i].length != n) {
                throw new IllegalArgumentException(
                    "All rows must have the same length."
                );
            }

            for (int j = 0; j < n; j++) {
                C[i][j] = A[i][j];
            }
        }

        return X;
    }

    /**
     * Make a deep copy of a matrix
     */
    public Matrix copy() {
        Matrix X = new Matrix(m, n);
        double[][] C = X.getArray();

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                C[i][j] = A[i][j];
            }
        }

        return X;
    }

    /**
     * Matrix determinant
     *
     * @return determinant
     */
    public double det() {
        return new LUDecomposition(this).det();
    }

    /**
     * Eigenvalue Decomposition
     *
     * @return EigenvalueDecomposition
     *
     * @see EigenvalueDecomposition
     */
    public EigenvalueDecomposition eig() {
        return new EigenvalueDecomposition(this);
    }

    /**
     * Get a single element.
     *
     * @param i Row index.
     * @param j Column index.
     *
     * @return A(i,j)
     *
     * @exception ArrayIndexOutOfBoundsException
     */
    public double get(int i, int j) {
        return A[i][j];
    }

    /**
     * Access the internal two-dimensional array.
     *
     * @return Pointer to the two-dimensional array of matrix elements.
     */
    public double[][] getArray() {
        return A;
    }

    /**
     * Copy the internal two-dimensional array.
     *
     * @return Two-dimensional array copy of matrix elements.
     */
    public double[][] getArrayCopy() {
        double[][] C = new double[m][n];

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                C[i][j] = A[i][j];
            }
        }

        return C;
    }

    /**
     * Get column dimension.
     *
     * @return n, the number of columns.
     */
    public int getColumnDimension() {
        return n;
    }

    /**
     * Make a one-dimensional column packed copy of the internal array.
     *
     * @return Matrix elements packed in a one-dimensional array by columns.
     */
    public double[] getColumnPackedCopy() {
        double[] vals = new double[m * n];

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                vals[i + (j * m)] = A[i][j];
            }
        }

        return vals;
    }

    /**
     * Get a submatrix.
     *
     * @param i0 Initial row index
     * @param i1 Final row index
     * @param j0 Initial column index
     * @param j1 Final column index
     *
     * @return A(i0:i1,j0:j1)
     *
     * @exception ArrayIndexOutOfBoundsException Submatrix indices
     */
    public Matrix getMatrix(int i0, int i1, int j0, int j1) {
        Matrix X = new Matrix(i1 - i0 + 1, j1 - j0 + 1);
        double[][] B = X.getArray();

        try {
            for (int i = i0; i <= i1; i++) {
                for (int j = j0; j <= j1; j++) {
                    B[i - i0][j - j0] = A[i][j];
                }
            }
        } catch (ArrayIndexOutOfBoundsException e) {
            throw new ArrayIndexOutOfBoundsException("Submatrix indices");
        }

        return X;
    }

    /**
     * Get a submatrix.
     *
     * @param i0 Initial row index
     * @param i1 Final row index
     * @param c Array of column indices.
     *
     * @return A(i0:i1,c(:))
     *
     * @exception ArrayIndexOutOfBoundsException Submatrix indices
     */
    public Matrix getMatrix(int i0, int i1, int[] c) {
        Matrix X = new Matrix(i1 - i0 + 1, c.length);
        double[][] B = X.getArray();

        try {
            for (int i = i0; i <= i1; i++) {
                for (int j = 0; j < c.length; j++) {
                    B[i - i0][j] = A[i][c[j]];
                }
            }
        } catch (ArrayIndexOutOfBoundsException e) {
            throw new ArrayIndexOutOfBoundsException("Submatrix indices");
        }

        return X;
    }

    /**
     * Get a submatrix.
     *
     * @param r Array of row indices.
     * @param i0 Initial column index
     * @param i1 Final column index
     *
     * @return A(r(:),j0:j1)
     *
     * @exception ArrayIndexOutOfBoundsException Submatrix indices
     */
    public Matrix getMatrix(int[] r, int j0, int j1) {
        Matrix X = new Matrix(r.length, j1 - j0 + 1);
        double[][] B = X.getArray();

        try {
            for (int i = 0; i < r.length; i++) {
                for (int j = j0; j <= j1; j++) {
                    B[i][j - j0] = A[r[i]][j];
                }
            }
        } catch (ArrayIndexOutOfBoundsException e) {
            throw new ArrayIndexOutOfBoundsException("Submatrix indices");
        }

        return X;
    }

    /**
     * Get a submatrix.
     *
     * @param r Array of row indices.
     * @param c Array of column indices.
     *
     * @return A(r(:),c(:))
     *
     * @exception ArrayIndexOutOfBoundsException Submatrix indices
     */
    public Matrix getMatrix(int[] r, int[] c) {
        Matrix X = new Matrix(r.length, c.length);
        double[][] B = X.getArray();

        try {
            for (int i = 0; i < r.length; i++) {
                for (int j = 0; j < c.length; j++) {
                    B[i][j] = A[r[i]][c[j]];
                }
            }
        } catch (ArrayIndexOutOfBoundsException e) {
            throw new ArrayIndexOutOfBoundsException("Submatrix indices");
        }

        return X;
    }

    /**
     * Get row dimension.
     *
     * @return m, the number of rows.
     */
    public int getRowDimension() {
        return m;
    }

    /**
     * Make a one-dimensional row packed copy of the internal array.
     *
     * @return Matrix elements packed in a one-dimensional array by rows.
     */
    public double[] getRowPackedCopy() {
        double[] vals = new double[m * n];

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                vals[(i * n) + j] = A[i][j];
            }
        }

        return vals;
    }

    /**
     * Generate identity matrix
     *
     * @param m Number of rows.
     * @param n Number of colums.
     *
     * @return An m-by-n matrix with ones on the diagonal and zeros elsewhere.
     */
    public static Matrix identity(int m, int n) {
        Matrix A = new Matrix(m, n);
        double[][] X = A.getArray();

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                X[i][j] = ((i == j) ? 1.0 : 0.0);
            }
        }

        return A;
    }

    /**
     * Matrix inverse or pseudoinverse
     *
     * @return inverse(A) if A is square, pseudoinverse otherwise.
     */
    public Matrix inverse() {
        return solve(identity(m, m));
    }

    /**
     * Returns the length of the vector Creation date: (2001-10-21 20.57.43)
     *
     * @return double
     *
     * @exception java.lang.IllegalArgumentException The exception description.
     */
    public double length()
        throws java.lang.IllegalArgumentException
    {
        double length;

        if (this.getColumnDimension() != 1) {
            throw new IllegalArgumentException(
                "Vector Lengths can only be applied to vectors. There can only be one column."
            );
        }

        if (this.getRowDimension() != 3) {
            throw new IllegalArgumentException(
                "The length method currently applies only to three dimensional vectors"
            );
        }

        //
        length = Math.sqrt(
                (this.get(0, 0) * this.get(0, 0)) +
                (this.get(1, 0) * this.get(1, 0)) +
                (this.get(2, 0) * this.get(2, 0))
            );

        return length;
    }

    /**
     * LU Decomposition
     *
     * @return LUDecomposition
     *
     * @see LUDecomposition
     */
    public LUDecomposition lu() {
        return new LUDecomposition(this);
    }

    /**
     * C = A - B
     *
     * @param B another matrix
     *
     * @return A - B
     */
    public Matrix minus(Matrix B) {
        checkMatrixDimensions(B);

        Matrix X = new Matrix(m, n);
        double[][] C = X.getArray();

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                C[i][j] = A[i][j] - B.A[i][j];
            }
        }

        return X;
    }

    /**
     * A = A - B
     *
     * @param B another matrix
     *
     * @return A - B
     */
    public Matrix minusEquals(Matrix B) {
        checkMatrixDimensions(B);

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                A[i][j] = A[i][j] - B.A[i][j];
            }
        }

        return this;
    }

    /**
     * One norm
     *
     * @return maximum column sum.
     */
    public double norm1() {
        double f = 0;

        for (int j = 0; j < n; j++) {
            double s = 0;

            for (int i = 0; i < m; i++) {
                s += Math.abs(A[i][j]);
            }

            f = Math.max(f, s);
        }

        return f;
    }

    /**
     * Two norm
     *
     * @return maximum singular value.
     */
    public double norm2() {
        return (new SingularValueDecomposition(this).norm2());
    }

    /**
     * Frobenius norm
     *
     * @return sqrt of sum of squares of all elements.
     */
    public double normF() {
        double f = 0;

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                f = Maths.hypot(f, A[i][j]);
            }
        }

        return f;
    }

    /**
     * Infinity norm
     *
     * @return maximum row sum.
     */
    public double normInf() {
        double f = 0;

        for (int i = 0; i < m; i++) {
            double s = 0;

            for (int j = 0; j < n; j++) {
                s += Math.abs(A[i][j]);
            }

            f = Math.max(f, s);
        }

        return f;
    }

    /**
     * C = A + B
     *
     * @param B another matrix
     *
     * @return A + B
     */
    public Matrix plus(Matrix B) {
        checkMatrixDimensions(B);

        Matrix X = new Matrix(m, n);
        double[][] C = X.getArray();

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                C[i][j] = A[i][j] + B.A[i][j];
            }
        }

        return X;
    }

    /**
     * A = A + B
     *
     * @param B another matrix
     *
     * @return A + B
     */
    public Matrix plusEquals(Matrix B) {
        checkMatrixDimensions(B);

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                A[i][j] = A[i][j] + B.A[i][j];
            }
        }

        return this;
    }

    /**
     * Print the matrix to stdout.   Line the elements up in columns with a
     * Fortran-like 'Fw.d' style format.
     *
     * @param w Column width.
     * @param d Number of digits after the decimal.
     */
    public void print(int w, int d) {
        print(new PrintWriter(System.out, true), w, d);
    }

    /**
     * Print the matrix to the output stream.   Line the elements up in columns
     * with a Fortran-like 'Fw.d' style format.
     *
     * @param output Output stream.
     * @param w Column width.
     * @param d Number of digits after the decimal.
     */
    public void print(PrintWriter output, int w, int d) {
        DecimalFormat format = new DecimalFormat();
        format.setDecimalFormatSymbols(new DecimalFormatSymbols(Locale.US));
        format.setMinimumIntegerDigits(1);
        format.setMaximumFractionDigits(d);
        format.setMinimumFractionDigits(d);
        format.setGroupingUsed(false);
        print(output, format, w + 2);
    }

    // DecimalFormat is a little disappointing coming from Fortran or C's printf.
    // Since it doesn't pad on the left, the elements will come out different
    // widths.  Consequently, we'll pass the desired column width in as an
    // argument and do the extra padding ourselves.

    /**
     * Print the matrix to the output stream.  Line the elements up in columns.
     * Use the format object, and right justify within columns of width
     * characters. Note that is the matrix is to be read back in, you probably
     * will want to use a NumberFormat that is set to US Locale.
     *
     * @param output the output stream.
     * @param format A formatting object to format the matrix elements
     * @param width Column width.
     *
     * @see java.text.DecimalFormat#setDecimalFormatSymbols
     */
    public void print(PrintWriter output, NumberFormat format, int width) {
        output.println(); // start on new line.

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                String s = format.format(A[i][j]); // format the number
                int padding = Math.max(1, width - s.length()); // At _least_ 1 space

                for (int k = 0; k < padding; k++) {
                    output.print(' ');
                }

                output.print(s);
            }

            output.println();
        }

        output.println(); // end with blank line.
    }

    /**
     * Print the matrix to stdout.  Line the elements up in columns. Use the
     * format object, and right justify within columns of width characters.
     * Note that is the matrix is to be read back in, you probably will want
     * to use a NumberFormat that is set to US Locale.
     *
     * @param format A  Formatting object for individual elements.
     * @param width Field width for each column.
     *
     * @see java.text.DecimalFormat#setDecimalFormatSymbols
     */
    public void print(NumberFormat format, int width) {
        print(new PrintWriter(System.out, true), format, width);
    }

    /**
     * QR Decomposition
     *
     * @return QRDecomposition
     *
     * @see QRDecomposition
     */
    public QRDecomposition qr() {
        return new QRDecomposition(this);
    }

    /**
     * Generate matrix with random elements
     *
     * @param m Number of rows.
     * @param n Number of colums.
     *
     * @return An m-by-n matrix with uniformly distributed random elements.
     */
    public static Matrix random(int m, int n) {
        Matrix A = new Matrix(m, n);
        double[][] X = A.getArray();

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                X[i][j] = Math.random();
            }
        }

        return A;
    }

    /**
     * Matrix rank
     *
     * @return effective numerical rank, obtained from SVD.
     */
    public int rank() {
        return new SingularValueDecomposition(this).rank();
    }

    /**
     * Read a matrix from a stream.  The format is the same the print method,
     * so printed matrices can be read back in (provided they were printed
     * using US Locale).  Elements are separated by whitespace, all the
     * elements for each row appear on a single line, the last row is followed
     * by a blank line.
     *
     * @param input the input stream.
     */
    public static Matrix read(BufferedReader input)
        throws java.io.IOException
    {
        StreamTokenizer tokenizer = new StreamTokenizer(input);

        // Although StreamTokenizer will parse numbers, it doesn't recognize
        // scientific notation (E or D); however, Double.valueOf does.
        // The strategy here is to disable StreamTokenizer's number parsing.
        // We'll only get whitespace delimited words, EOL's and EOF's.
        // These words should all be numbers, for Double.valueOf to parse.
        tokenizer.resetSyntax();
        tokenizer.wordChars(0, 255);
        tokenizer.whitespaceChars(0, ' ');
        tokenizer.eolIsSignificant(true);

        java.util.Vector v = new java.util.Vector();

        // Ignore initial empty lines
        while (tokenizer.nextToken() == StreamTokenizer.TT_EOL) {
            ;
        }

        if (tokenizer.ttype == StreamTokenizer.TT_EOF) {
            throw new java.io.IOException("Unexpected EOF on matrix read.");
        }

        do {
            v.addElement(Double.valueOf(tokenizer.sval)); // Read & store 1st row.
        } while (tokenizer.nextToken() == StreamTokenizer.TT_WORD);

        int n = v.size(); // Now we've got the number of columns!
        double[] row = new double[n];

        for (int j = 0; j < n; j++) // extract the elements of the 1st row.
         {
            row[j] = ((Double) v.elementAt(j)).doubleValue();
        }

        v.removeAllElements();
        v.addElement(row); // Start storing rows instead of columns.

        while (tokenizer.nextToken() == StreamTokenizer.TT_WORD) {
            // While non-empty lines
            v.addElement(row = new double[n]);

            int j = 0;

            do {
                if (j >= n) {
                    throw new java.io.IOException(
                        "Row " + v.size() + " is too long."
                    );
                }

                row[j++] = Double.valueOf(tokenizer.sval).doubleValue();
            } while (tokenizer.nextToken() == StreamTokenizer.TT_WORD);

            if (j < n) {
                throw new java.io.IOException(
                    "Row " + v.size() + " is too short."
                );
            }
        }

        int m = v.size(); // Now we've got the number of rows.
        double[][] A = new double[m][];
        v.copyInto(A); // copy the rows out of the vector

        return new Matrix(A);
    }

    /**
     * Set a single element.
     *
     * @param i Row index.
     * @param j Column index.
     * @param s A(i,j).
     *
     * @exception ArrayIndexOutOfBoundsException
     */
    public void set(int i, int j, double s) {
        A[i][j] = s;
    }

    /**
     * Set the complete data.
     *
     * @param X other matrix
     */
    public void setMatrix(Matrix X) {
	for (int i = 0; i < m; i++) {
	    for (int j = 0; j < n; j++) {
		A[i][j] = X.get(i, j);
	    }
	}
    }

    
    /**
     * Set a submatrix.
     *
     * @param i0 Initial row index
     * @param i1 Final row index
     * @param j0 Initial column index
     * @param j1 Final column index
     * @param X A(i0:i1,j0:j1)
     *
     * @exception ArrayIndexOutOfBoundsException Submatrix indices
     */
    public void setMatrix(int i0, int i1, int j0, int j1, Matrix X) {
        try {
            for (int i = i0; i <= i1; i++) {
                for (int j = j0; j <= j1; j++) {
                    A[i][j] = X.get(i - i0, j - j0);
                }
            }
        } catch (ArrayIndexOutOfBoundsException e) {
            throw new ArrayIndexOutOfBoundsException("Submatrix indices");
        }
    }

    /**
     * Set a submatrix.
     *
     * @param i0 Initial row index
     * @param i1 Final row index
     * @param c Array of column indices.
     * @param X A(i0:i1,c(:))
     *
     * @exception ArrayIndexOutOfBoundsException Submatrix indices
     */
    public void setMatrix(int i0, int i1, int[] c, Matrix X) {
        try {
            for (int i = i0; i <= i1; i++) {
                for (int j = 0; j < c.length; j++) {
                    A[i][c[j]] = X.get(i - i0, j);
                }
            }
        } catch (ArrayIndexOutOfBoundsException e) {
            throw new ArrayIndexOutOfBoundsException("Submatrix indices");
        }
    }

    /**
     * Set a submatrix.
     *
     * @param r Array of row indices.
     * @param j0 Initial column index
     * @param j1 Final column index
     * @param X A(r(:),j0:j1)
     *
     * @exception ArrayIndexOutOfBoundsException Submatrix indices
     */
    public void setMatrix(int[] r, int j0, int j1, Matrix X) {
        try {
            for (int i = 0; i < r.length; i++) {
                for (int j = j0; j <= j1; j++) {
                    A[r[i]][j] = X.get(i, j - j0);
                }
            }
        } catch (ArrayIndexOutOfBoundsException e) {
            throw new ArrayIndexOutOfBoundsException("Submatrix indices");
        }
    }

    /**
     * Set a submatrix.
     *
     * @param r Array of row indices.
     * @param c Array of column indices.
     * @param X A(r(:),c(:))
     *
     * @exception ArrayIndexOutOfBoundsException Submatrix indices
     */
    public void setMatrix(int[] r, int[] c, Matrix X) {
        try {
            for (int i = 0; i < r.length; i++) {
                for (int j = 0; j < c.length; j++) {
                    A[r[i]][c[j]] = X.get(i, j);
                }
            }
        } catch (ArrayIndexOutOfBoundsException e) {
            throw new ArrayIndexOutOfBoundsException("Submatrix indices");
        }
    }

    /**
     * Solve AX = B
     *
     * @param B right hand side
     *
     * @return solution if A is square, least squares solution otherwise
     */
    public Matrix solve(Matrix B) {
        return ((m == n) ? (new LUDecomposition(this)).solve(B)
                         : (new QRDecomposition(this)).solve(B));
    }

    /**
     * Solve XA = B, which is also A'X' = B'
     *
     * @param B right hand side
     *
     * @return solution if A is square, least squares solution otherwise.
     */
    public Matrix solveTranspose(Matrix B) {
        return transpose().solve(B.transpose());
    }

    /**
     * Singular Value Decomposition
     *
     * @return SingularValueDecomposition
     *
     * @see SingularValueDecomposition
     */
    public SingularValueDecomposition svd() {
        return new SingularValueDecomposition(this);
    }

    /**
     * Multiply a matrix by a scalar, C = sA
     *
     * @param s scalar
     *
     * @return sA
     */
    public Matrix times(double s) {
        Matrix X = new Matrix(m, n);
        double[][] C = X.getArray();

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                C[i][j] = s * A[i][j];
            }
        }

        return X;
    }

    /**
     * Linear algebraic matrix multiplication, A  B
     *
     * @param B another matrix
     *
     * @return Matrix product, A  B
     *
     * @exception IllegalArgumentException Matrix inner dimensions must agree.
     */
    public Matrix times(Matrix B) {
        if (B.m != n) {
            throw new IllegalArgumentException(
                "Matrix inner dimensions must agree."
            );
        }

        Matrix X = new Matrix(m, B.n);
        double[][] C = X.getArray();
        double[] Bcolj = new double[n];

        for (int j = 0; j < B.n; j++) {
            for (int k = 0; k < n; k++) {
                Bcolj[k] = B.A[k][j];
            }

            for (int i = 0; i < m; i++) {
                double[] Arowi = A[i];
                double s = 0;

                for (int k = 0; k < n; k++) {
                    s += (Arowi[k] * Bcolj[k]);
                }

                C[i][j] = s;
            }
        }

        return X;
    }

    /**
     * Multiply a matrix by a scalar in place, A = sA
     *
     * @param s scalar
     *
     * @return replace A by sA
     */
    public Matrix timesEquals(double s) {
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                A[i][j] = s * A[i][j];
            }
        }

        return this;
    }

    /**
     * Matrix trace.
     *
     * @return sum of the diagonal elements.
     */
    public double trace() {
        double t = 0;

        for (int i = 0; i < Math.min(m, n); i++) {
            t += A[i][i];
        }

        return t;
    }

    /**
     * Matrix transpose.
     *
     * @return A'
     */
    public Matrix transpose() {
        Matrix X = new Matrix(n, m);
        double[][] C = X.getArray();

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                C[j][i] = A[i][j];
            }
        }

        return X;
    }

    /**
     * Unary minus
     *
     * @return -A
     */
    public Matrix uminus() {
        Matrix X = new Matrix(m, n);
        double[][] C = X.getArray();

        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                C[i][j] = -A[i][j];
            }
        }

        return X;
    }

    /**
     * This method calculates the vectorProduct between two matrices. The
     * matrices must be three dimensional. Creation date: (2001-10-21
     * 19.46.07) Jonas Forssell
     *
     * @param a Jama.Matrix
     * @param b Jama.Matrix
     *
     * @return result_vector Jama.Matrix
     *
     * @exception java.lang.IllegalArgumentException The exception description.
     */
    public Matrix vectorProduct(Jama.Matrix B)
        throws java.lang.IllegalArgumentException
    {
        //
        Matrix result_vector = new Matrix(3, 1);

        //
        if ((B.getColumnDimension() != 1) || (this.getColumnDimension() != 1)) {
            throw new IllegalArgumentException(
                "Vector Products can only be applied to vectors. There can only be one column."
            );
        }

        if ((B.getRowDimension() != 3) || (this.getRowDimension() != 3)) {
            throw new IllegalArgumentException(
                "Matrix inner dimensions must agree."
            );
        }

        //
        // Calculate the vector product term by term.
        result_vector.set(
            0, 0,
            (this.get(1, 0) * B.get(2, 0)) - (B.get(1, 0) * this.get(2, 0))
        );
        result_vector.set(
            1, 0,
            (this.get(2, 0) * B.get(0, 0)) - (B.get(2, 0) * this.get(0, 0))
        );
        result_vector.set(
            2, 0,
            (this.get(0, 0) * B.get(1, 0)) - (B.get(0, 0) * this.get(1, 0))
        );

        // Now, return the completed vector.
        return result_vector;
    }

    /** The following methods are custom written to allow patching of
     * variable values during synchronization of replicated objects
     * in the cluster version of Impact.
     * 
     * They are replacements and extensions to methods provided by
     * default in the JavaParty environment.
     *
     */
    
    
    public void appendTo(ToString s) {
        s.append("A", A);
    }

    // Implementation of the Patchable interface
    public void createPatch(Object _copy, uka.patch.PatchOutput po)
        throws java.io.IOException
    {
        Matrix copy = (Matrix) _copy;

        if (this.n != copy.n) {
            throw new AssertionError("Matrix dimension has changed");
        }

        if (this.m != copy.m) {
            throw new AssertionError("Matrix dimension has changed");
        }

        for (int row = 0; row < getRowDimension(); row++) {
            for (int col = 0; col < getColumnDimension(); col++) {
                if (po.writeDiff(this.get(row, col) - copy.get(row, col), 0.0d)) {
                    copy.set(row, col, this.get(row, col));
                }
            }
        }
    }

    public void applyPatch(Object _copy, uka.patch.PatchInput pi)
        throws java.io.IOException, ClassNotFoundException
    {
        Matrix copy = (Matrix) _copy;
	
	// Assertion
	//
        // if (((PatchReader) pi).objects.findID(A) != -1) {
	//     throw new AssertionError("A reference to the private matrix state was given away");
	// }

        if (this.n != copy.n) {
            throw new AssertionError("Matrix dimension has changed");
        }

        if (this.m != copy.m) {
            throw new AssertionError("Matrix dimension has changed");
        }

        for (int row = 0; row < getRowDimension(); row++) {
            for (int col = 0; col < getColumnDimension(); col++) {
                if (pi.hasDiff()) {
                    double dd = pi.getDiffAsDouble();
                    this.set(row, col, this.get(row, col) + dd);
                    copy.set(row, col, copy.get(row, col) + dd);
                }
            }
        }
    }

    public Object clone() {
        // return a deep copy
        return copy();
    }

    public void descendReferences(uka.patch.ReferenceConsumer c)
        throws java.io.IOException
    {
        // empty
    }

    public void filterReferences(uka.patch.ReferenceFilter f) {
    }

    // *****************************************
    // Implementation of the Transportable interface
    
   public static final uka.transport.TransportDescriptor TRANSPORT_DESCRIPTOR = 
       new uka.transport.TransportDescriptor() {
	   public Object unmarshalReference(uka.transport.UnmarshalStream s, int id)
	       throws java.io.IOException, ClassNotFoundException 
	   {
	       return new Matrix(s, id);
	   }

	   public boolean unmarshal(Object obj, uka.transport.UnmarshalStream s) 
	       throws ClassNotFoundException, java.io.IOException 
	   {
	       ((Matrix) obj).unmarshal(s);
	       return false;
	   }

	   public void marshalReference(Object obj, uka.transport.MarshalStream s) 
	       throws java.io.IOException 
	   {
	       ((Matrix) obj).marshalReference(s);
	   }

	   public void marshal(Object obj, uka.transport.MarshalStream s) 
	       throws java.io.IOException 
	   {
	       ((Matrix) obj).marshal(s);
	   }

	   public Object deepClone(Object orig, int id, uka.transport.DeepClone _helper) 
	       throws CloneNotSupportedException 
	   {
	       Matrix c = ((Matrix) orig).copy();
	       _helper.add(id, c);
	       return c;
	       
	   }

	   public boolean deepCloneReferences(Object orig, Object copy, uka.transport.DeepClone _helper) throws CloneNotSupportedException {
	    	return false;
	    }
	   
	   public Class getType() {
	       return Matrix.class;
	   }
       };

    public uka.transport.TransportDescriptor getTransportDescriptor() {
	return TRANSPORT_DESCRIPTOR;
    }

    private static final int _SIZE = uka.transport.BasicIO.SIZEOF_int + uka.transport.BasicIO.SIZEOF_int;
    
    public Matrix(uka.transport.UnmarshalStream _stream, int _id) 
	throws java.io.IOException, ClassNotFoundException 
    {
	_stream.register(this, _id);
    }

    public void unmarshal(uka.transport.UnmarshalStream _stream) 
	throws java.io.IOException, ClassNotFoundException 
    {
	_stream.request(Matrix._SIZE);
	byte[] _buffer = _stream.getBuffer();
	int _pos = _stream.getPosition();
	this.n = uka.transport.BasicIO.extractInt(_buffer, _pos);
	_pos += uka.transport.BasicIO.SIZEOF_int;
	this.m = uka.transport.BasicIO.extractInt(_buffer, _pos);
	_pos += uka.transport.BasicIO.SIZEOF_int;
	_stream.accept(Matrix._SIZE);

	this.A = uka.transport.ValueIO.readValueArrayArrayDouble(_stream);
    }

    public void marshalReference(uka.transport.MarshalStream _stream) 
	throws java.io.IOException 
    {
    }

    public void marshal(uka.transport.MarshalStream _stream) 
	throws java.io.IOException 
    {
	_stream.reserve(Matrix._SIZE);
	byte[] _buffer = _stream.getBuffer();
	int _pos = _stream.getPosition();
	_pos = uka.transport.BasicIO.insert(_buffer, _pos, this.n);
	_pos = uka.transport.BasicIO.insert(_buffer, _pos, this.m);
	_stream.deliver(_SIZE);

	uka.transport.ValueIO.writeValue(_stream, this.A);
    }

    public Object flatClone() {
    	return copy();
    }
        
    
}

