matrix.hh

/*
 * matrix.hh
 *
 * License: Artistic License, see file LICENSE.TXT or 
 *          https://opensource.org/licenses/artistic-license-1.0
 */
 
#ifndef _MATRIX_HH
#define _MATRIX_HH
 
// standard C/C++ includes
#include <vector>
#include <ostream>  // for operator<<
 
 
using namespace std;
 
template <class T>
class Matrix {
public:
    typedef T         value_t;
public:
    Matrix(int n = 0, int m = 0) {
    init(n,m);
    }
    ~Matrix( ){ 
    delete[] data;
    }
    value_t* operator[] ( int i ) {
    return data + i*width;
    }
    const value_t* operator[] ( int i ) const {
    return data + i*width;
    }
    value_t& operator() ( int i, int j ) {
    return (*this)[i][j];
    }
    const value_t& operator() ( int i, int j ) const {
    return (*this)[i][j];
    }
    vector<T> getRow(int i) const {
    return vector<T>(data + i*width, data + (i+1)*width);
    }
    vector<T> getColumn(int j) const {
    vector<T> result;
    result.reserve(height);
    for (value_t* p = data + j; p < data + size; p+=width)
        result.push_back(*p);
    return result;
    }
    int getColSize( ) const {
    return height;
    }
    int getRowSize( ) const {
    return width;
    }
    void operator=(const Matrix<value_t>& mat) {
    resize(mat.height, mat.width);
    for (int i=0; i<size; i++) 
        data[i] = mat.data[i];
    }
    void assign(int n, int m, value_t t = value_t()) {
    resize(n,m);
    for (int i=0; i<size; i++) 
        data[i] = t;
    }
    friend ostream& operator<<(ostream& out, const Matrix<value_t>& mat) {
    for (int i = 0; i < mat.size; i++) {
        out << mat.data[i];
        if (i+1 % mat.width)
        out << "\t";
        else
        out << endl;
    }
    return out;
    }
 
private:
    void resize(int n = 0, int m = 0) {
    if (n == height && m == width) 
        return;
    delete[] data;
    init(n,m);
    }
    void init(int n = 0, int m = 0) {
    if (n>0 && m>0) {
        height=n; width=m; size=n*m;
        data  = new value_t[size];
    } else {
        size=height=width=0; data=0;
    }
    }
    int     height;  // n
    int     width;  // m
    int     size;    // n*m;
    value_t   *data;  // the nxm matrix
};
 
#endif   //  _MATRIX_HH