math.utils

Class Matrix

java.lang.Object

math.utils.Matrix

public class Matrix
extends java.lang.Object

class Matrix

Field Summary

Fields

Modifier and Type	Field and Description
static double	tolerance The tolerance used for solving linear equations.

Constructor Summary

Constructors

Constructor and Description
Matrix() Constructs a new Matrix, with 1 row and 1 column, initialized to 1.
Matrix(double[][] coef) Constructs a new Matrix, initialized with the given coefficients.
Matrix(int nbRows, int nbCols) Initializes a new Matrix with the given number of rows and columns.

Method Summary

Modifier and Type	Method and Description
double	getCoef(int row, int col) Returns the coef.
int	getColumns() Returns the number of columns.
int	getRows() Returns the number of rows.
Matrix	getTranspose() Returns the transposed matrix, without changing the inner coefficients of the original matrix.
boolean	isSquare() Returns true if the matrix is square, i.e.
double[]	multiplyWith(double[] coefs) Returns the result of the multiplication of the matrix with the given vector.
double[]	multiplyWith(double[] src, double[] res) Returns the result of the multiplication of the matrix with the given vector.
Matrix	multiplyWith(Matrix matrix) Returns the result of the multiplication of the matrix with another one.
void	setCoef(int row, int col, double coef) Sets the coef to the given value.
void	setToIdentity() Fills the matrix with zeros everywhere, except on the main diagonal, filled with ones.
double[]	solve(double[] vector) Computes the solution of a linear system, using the Gauss-Jordan algorithm.
java.lang.String	toString() Returns a String representation of the elements of the Matrix
void	transpose() Transposes the matrix, changing the inner coefficients.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

tolerance

public static double tolerance

The tolerance used for solving linear equations. Equal to 1e-14 by default.

Constructor Detail

Matrix

public Matrix()

Constructs a new Matrix, with 1 row and 1 column, initialized to 1.

Matrix

public Matrix(int nbRows,
              int nbCols)

Initializes a new Matrix with the given number of rows and columns.

Matrix

public Matrix(double[][] coef)

Constructs a new Matrix, initialized with the given coefficients.

Method Detail

getCoef

public double getCoef(int row,
                      int col)

Returns the coef. row and col are between 1 and the number of rows and columns.

getRows

public int getRows()

Returns the number of rows.

getColumns

public int getColumns()

Returns the number of columns.

isSquare

public boolean isSquare()

Returns true if the matrix is square, i.e. the number of rows equals the number of columns.

setCoef

public void setCoef(int row,
                    int col,
                    double coef)

Sets the coef to the given value. row and col are between 1 and the number of rows and columns.

multiplyWith

public Matrix multiplyWith(Matrix matrix)

Returns the result of the multiplication of the matrix with another one. The content of the matrix is not modified.

Throws:

java.lang.IllegalArgumentException - if the size of matrices do not match

multiplyWith

public double[] multiplyWith(double[] coefs)

Returns the result of the multiplication of the matrix with the given vector. The content of the matrix is not modified.

Throws:

java.lang.NullPointerException - if input array is null

java.lang.IllegalArgumentException - if size of vector and of matrix do not match

multiplyWith

public double[] multiplyWith(double[] src,
                             double[] res)

Returns the result of the multiplication of the matrix with the given vector. The content of the matrix is not modified.

Throws:

java.lang.NullPointerException - if input vector is null

java.lang.IllegalArgumentException - if size of vector and of matrix do not match

transpose

public void transpose()

Transposes the matrix, changing the inner coefficients.

getTranspose

public Matrix getTranspose()

Returns the transposed matrix, without changing the inner coefficients of the original matrix.

solve

public double[] solve(double[] vector)

Computes the solution of a linear system, using the Gauss-Jordan algorithm. The inner coefficients of the matrix are not modified.

Throws:

java.lang.NullPointerException - if input vector is null

java.lang.IllegalArgumentException - if size of vector and of matrix do not match

java.lang.UnsupportedOperationException - if the matrix is not square

java.lang.ArithmeticException - if the algorithm could not find pivot greater than tolerance

setToIdentity

public void setToIdentity()

Fills the matrix with zeros everywhere, except on the main diagonal, filled with ones.

toString

public java.lang.String toString()

Returns a String representation of the elements of the Matrix

Overrides:

toString in class java.lang.Object