repicea.math

Class MatrixUtility

java.lang.Object

repicea.math.MatrixUtility

public class MatrixUtility
extends java.lang.Object

This class provides some matrix operations. Some update the first argument matrix instead of creating a new instance. Useful for optimizing some operations.

Constructor Summary

Constructors

Constructor and Description
MatrixUtility()

Method Summary

Modifier and Type	Method and Description
static void	add(Matrix a, Matrix b) This method adds a matrix to a reference matrix.
static void	elementWiseMultiply(Matrix a, Matrix b) This method returns the element wise product of two matrices.
static Matrix	getIdentityMatrix(int i) This method returns an identity matrix of size i.
static void	scalarMultiply(Matrix a, double b) This method multiplies all the element of a matrix by a double.
static void	subtract(Matrix a, Matrix b) This method subtracts a matrix from a reference matrix.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MatrixUtility

public MatrixUtility()

Method Detail

add

public static void add(Matrix a,
                       Matrix b)

This method adds a matrix to a reference matrix. The result is returned in the reference matrix. NOTE: No new matrix instance is created.

Parameters:

a - a Matrix instance (the reference)

b - a Matrix instance

subtract

public static void subtract(Matrix a,
                            Matrix b)

This method subtracts a matrix from a reference matrix. The result is returned in the reference matrix. NOTE: No new matrix instance is created.

Parameters:

a - a Matrix instance (the reference)

b - a Matrix instance

elementWiseMultiply

public static void elementWiseMultiply(Matrix a,
                                       Matrix b)

This method returns the element wise product of two matrices. The result is returned in the first matrix. NOTE: No new matrix instance is created.

Parameters:

a - a Matrix instance (the reference)

b - a Matrix instance

scalarMultiply

public static void scalarMultiply(Matrix a,
                                  double b)

This method multiplies all the element of a matrix by a double. The result is returned in the same matrix. NOTE: No new matrix instance is created.

Parameters:

a - a Matrix instance

b - a double instance

getIdentityMatrix

public static Matrix getIdentityMatrix(int i)

This method returns an identity matrix of size i.

Parameters:

i - the dimension of the matrix

Returns:

a Matrix instance