#ifndef _MATRIX_H#define _MATRIX_H#include "defines.h"namespace annie{/** A class for 2-dimensional matrices.  * This probably isn't the most efficient way to do matrix operations,  * use of optimized matrix libraries would be preferable, but this should  * suffice for most applications  */class Matrix{private:	int _m,_n;	real **_M;	void _allocateMatrix(int m, int n);	void _freeMatrix();public:	/** Create a matrix	  * Note that the elements of the matrix will be random, they have	  * NOT been initialized to zero or any other value	  * @param m Number of rows	  * @param n Number of columns	  */	Matrix(int m,int n);	/// Copy constructor	Matrix(Matrix &M);	/// Similar to the copy constructor	Matrix(Matrix *M);	virtual ~Matrix();	/// Prints the matrix on the screen	virtual void print();	/** Value of a given cell in the matrix	  * @param i The row in the matrix	  * @param j The column in the matrix	  * @return Value of the element at the ith row and jth column	  */	virtual real& elementAt(int i,int j);	/** Multiplies the matrix with the given matrix and returns	  * a new matrix.	  * You will have to deallocate the product matrix with delete.	  * @param other The matrix to multiply with	  * @return The product matrix	  * @throws Exception if the matrices cannot be multiplied	  */	virtual Matrix *multiply(Matrix &other);	/** Multiplies the matrix with the given matrix and returns	  * a new matrix.	  * You will have to deallocate the product matrix with delete.	  * @param other The matrix to multiply with	  * @return The product matrix	  * @throws Exception if the matrices cannot be multiplied	  */	virtual Matrix *multiply(Matrix *other);	/// Multiplies the matrix with the scalar quantity provided	virtual void multiply(real f);	/// Swaps the ith and jth row of the matrix	virtual void swapRows(int i, int j);	/** Finds the transpose of the matrix	  * You will have to deallocate the tranpose matrix with delete.	  * @return A new matrix which is the transpose of the current matrix	  */	virtual Matrix *transpose();	/** Finds the inverse of the matrix	  * You will have to deallocate the inverse matrix with delete.	  * Uses the gaussian elmination technique to calculate the inverse	  * @return A new matrix which is the inverse of this matrix	  * @throws Exception if the matrix is not invertible.	  */	virtual Matrix *inverse();	/** Returns the identity matrix of size nxn.	  * You will have to deallocate the identity matrix with delete	  * @param n The number of rows/columns in the matrix	  * @return The square identity matrix of nxn	  */	static Matrix *Identity(int n);	/// Prints matrix to the provided output stream	friend std::ostream& operator << (std::ostream& s, Matrix &M);};}; //namespace annie#endif // define _MATRIX_H