I put the code you posted just above mine into a project with an empty main, so it wasn't that code that was the problem. I just added stuff to make sure it compiles (if you don't use a template it won't always get run through the compiler).
I don't understand the errors you posted, so perhaps there is something wrong somewhere else in your original project that is causing strange parse errors. I dunno.
You tested it with an empty main, but when I tested it at first, I had no main() at all.
Alright, I'm done for today, I'll post it here for you guys so you can comment, criticize and suggest ideas. I haven't finished the Determinant() function. Right now it can only calculate determinants for matrice from 1x1 to 3x3 but no more since I haven't fully understood the LU decomposition method for faster calculation of determinants on large matrices.
Anyway, here's the code. I haven't fully tested it but most of it works (tested) :PS: The Output() function is there only for testing purposes, I will take it out when I have finished testing / implementing.Code:#ifndef MATRIX_H_INCLUDED #define MATRIX_H_INCLUDED #include <iostream> #include <vector> #include <memory> template < class T > class Matrix { public: typedef std::auto_ptr< Matrix< T > > MATRIX_PTR; Matrix(int Cols = 0, int Rows = 0); void Output( ) { for(int j = 0; j < Rows; j++) { for(int i = 0; i < Cols; i++) { std::cout << Data[j][i]; } std::cout << std::endl; } } void SetElement(int col, int row, T val); void InterchangeRows(int row_1, int row_2); void InterchangeCols(int col_1, int col_2); bool LowerTriangle( ) const; bool UpperTriangle( ) const; bool SquareMatrix( ) const; T Determinant( ); MATRIX_PTR& Minor(int col, int row); private: unsigned int Rows, Cols; std::vector< std::vector< T > > Data; MATRIX_PTR Temp; }; template < class T > Matrix< T >::Matrix< T >(int n_cols, int n_rows) : Cols(n_cols), Rows(n_rows) { if(n_cols > 0 && n_rows > 0) { for(int i = 0; i < Rows; i++) { Data.push_back(std::vector< T >( )); Data[i].insert(Data[i].begin(), Cols, 0); } } else { Cols = Rows = 0; } } template < class T > void Matrix< T >::SetElement(int col, int row, T val) { if(col >= 0 && row >= 0) { Data[row][col] = val; } } template < class T > void Matrix< T >::InterchangeRows(int row_1, int row_2) { if(row_1 != row_2 && (row_1 >= 0 && row_2 >= 0)) { Data[row_1].swap(Data[row_2]); } } template < class T> void Matrix< T >::InterchangeCols(int col_1, int col_2) { // Parentheses for easier reading only // Make sure both columns are different and range in [0, Cols[ if((col_1 != col_2) && (col_1 >= 0) && (col_2 >= 0) && (col_1 < Cols) && (col_2 < Cols)) { for(int j = 0; j < Rows; j++) { T tmp = Data[j][col_1]; Data[j][col_1] = Data[j][col_2]; Data[j][col_2] = tmp; } } } template < class T > bool Matrix< T >::LowerTriangle( ) const { // Only square matrixes bigger than 0,0 if(SquareMatrix() && (Cols != 0 && Rows != 0)) { for(int j = 0; j < Rows; j++) { for(int i = 0; i < Cols; i++) { if(i > j && Data[j][i] != 0) { return false; } } } } else { return false; } return true; } template < class T > bool Matrix< T >::UpperTriangle( ) const { // Only square matrixes bigger than 0,0 if(SquareMatrix() && (Cols != 0 && Rows != 0)) { for(int j = 0; j < Rows; j++) { for(int i = 0; i < Cols; i++) { if(i < j && Data[j][i] != 0) { return false; } } } } else { return false; } return true; } template < class T > bool Matrix< T >::SquareMatrix( ) const { return (Rows == Cols); } template < class T > T Matrix< T >::Determinant( ) { if(SquareMatrix( )) { if(Cols == 0 && Rows == 0) { return static_cast< T >(0); } else if(Cols == 1 && Rows == 1) { return Data[0][0]; } else if(Cols == 2 && Rows == 2) { return (Data[0][0] * Data[1][1] - Data[0][1] * Data[1][0]); } else if(Cols == 3 && Rows == 3) { if(UpperTriangle( ) || LowerTriangle( )) { return (Data[0][0] * Data[1][1] * Data[2][2]); } return (Data[0][0] * Data[1][1] * Data[2][2] + Data[0][2] * Data[1][0] * Data[2][1] + Data[0][1] * Data[1][2] * Data[2][0] - Data[0][2] * Data[1][1] * Data[2][0] - Data[0][0] * Data[1][2] * Data[2][1] - Data[0][1] * Data[1][0] * Data[2][2]); } // Let's use the M = LU decomposition method for faster processing else { } } } template < class T > typename Matrix< T >::MATRIX_PTR& Matrix< T >::Minor(int col, int row) { if(SquareMatrix( ) && (Rows != 0 && Cols != 0)) { Temp.reset(new Matrix< T >); int y = 0; // Move horizontally then down in the matrix for(int j = 0; j < Rows; j++) { if(j != row) { // We're on a new line... Temp->Data.push_back(std::vector< T >( )); for(int i = 0; i < Cols; i++) { if(i != col) { (Temp->Data[y]).push_back(Data[j][i]); } } y++; } } } Temp->Cols = Temp->Data[0].size(); Temp->Rows = Temp->Data.size(); return Temp; } #endif // MATRIX_H_INCLUDED
Thanks again !
some comments
your constructor arguements Cols and Rows have different names in the implementation (n_cols, n_rows). This is legal but bad style. Cols and Rows are both members and arguements in the class def. Personally I like to differentiate members somehow (this->var, m_var, var_, whatever you like). are default arguements of 0 useful?Code:template < class T > class Matrix { public: Matrix(int Cols = 0, int Rows = 0); private: unsigned int Rows, Cols; }; template < class T > Matrix< T >::Matrix< T >(int n_cols, int n_rows) : Cols(n_cols), Rows(n_rows) { if(n_cols > 0 && n_rows > 0) { for(int i = 0; i < Rows; i++) { Data.push_back(std::vector< T >( )); Data[i].insert(Data[i].begin(), Cols, 0); } } else { Cols = Rows = 0; } }
Also why are the arguements ints, but the members unsigned ints? surely the arguements should also be unsigned?
The else is redundant. Cols and Rows have already been initiated to 0 in your initialiser list.
you should reserve() your vectors since you know the size. It will increase efficiency.
same comment about unsigned int parameters.Code:void SetElement(int col, int row, T val); void InterchangeRows(int row_1, int row_2); void InterchangeCols(int col_1, int col_2);
I won't comment on the matrix math since it's been a while since I used it in anger.
hmmm... this isn't really the best way to use auto_ptr.Code:template < class T > typename Matrix< T >::MATRIX_PTR& Matrix< T >::Minor(int col, int row) { // snip... Temp.reset(new Matrix< T >); // snip... return Temp; }
consider the following
You should really return an auto_ptr (not a reference) and forget your Temp member. This will allow the client to take ownership of the minor matrix.Code:Matrix<float> agentSmith(666, 666); MATRIX_PTR &neo = agentSmith.Minor(); // some code MATRIX_PTR &trinity = agentSmith.Minor(); // arrghhh neo was killed!!
other than that, looks good. keep it up.
"I saw a sign that said 'Drink Canada Dry', so I started"
-- Brendan Behan
Free Compiler: Visual C++ 2005 Express
If you program in C++, you need Boost. You should also know how to use the Standard Library (STL). Want to make games? After reading this, I don't like WxWidgets anymore.Want to add some scripting to your App?
Thanks ! I'll fix that up when I get back from College this afternoon. I'll add a copy constructor as well and operators such as multiplication, addition, substraction, equality, assignment... I'd also like to make a function to calculate the order of the matrix (usually noted 'k'). I'll try to find the other thread where someone mentioned points that he/she'd like to have in a matrix library. I might as well make a vector class after.
Here we go, I quite a bit of stuff and I still need to work on determinants and more other stuff (making it possible to add vectors of numbers, adding scalar * matrix, adding matrix transpose...). I'm not completely satisfied with the design yet but it's not that ugly either.
Here it is:
Code:#ifndef MATRIX_H_INCLUDED #define MATRIX_H_INCLUDED #include <iostream> #include <vector> #include <memory> template < class T > class Matrix { public: typedef std::auto_ptr< Matrix< T > > MATRIX_PTR; Matrix(unsigned int n_cols = 0, unsigned int n_rows = 0); Matrix(const Matrix& m); void Output( ) { for(int j = 0; j < Rows; j++) { for(int i = 0; i < Cols; i++) { std::cout << Data[j][i]; } std::cout << std::endl; } } void SetElement(unsigned int col, unsigned int row, T val); void InterchangeRows(unsigned int row_1, unsigned int row_2); void InterchangeCols(unsigned int col_1, unsigned int col_2); bool LowerTriangle( ) const; bool UpperTriangle( ) const; bool SquareMatrix( ) const; T Determinant( ); static MATRIX_PTR IdentityMatrix(unsigned int size); static MATRIX_PTR NullMatrix(unsigned int size); MATRIX_PTR Minor(unsigned int col, unsigned int row); Matrix< T >& operator = (const Matrix< T >&); Matrix< T >& operator += (const Matrix< T >&); Matrix< T >& operator -= (const Matrix< T >&); Matrix< T > operator * (const Matrix< T >&) const; Matrix< T > operator - (const Matrix< T >&) const; Matrix< T > operator + (const Matrix< T >&) const; private: unsigned int Rows, Cols; std::vector< std::vector< T > > Data; }; template < class T > Matrix< T >::Matrix< T >(unsigned int n_cols, unsigned int n_rows) : Cols(n_cols), Rows(n_rows) { if(Cols > 0 && Rows > 0) { Data.reserve(Rows); for(int i = 0; i < Rows; i++) { Data.push_back(std::vector< T >( )); Data[i].reserve(Cols); Data[i].insert(Data[i].begin(), Cols, 0); } } else if(Cols < 0 && Rows < 0) { Cols = Rows = 0; } } template < class T > Matrix< T >::Matrix< T >(const Matrix& m) { *this = m; } template < class T > void Matrix< T >::SetElement(unsigned int col, unsigned int row, T val) { if(col >= 0 && row >= 0 && col < Cols && row < Rows) { Data[row][col] = val; } } template < class T > void Matrix< T >::InterchangeRows(unsigned int row_1, unsigned int row_2) { if(row_1 != row_2 && (row_1 >= 0 && row_2 >= 0)) { Data[row_1].swap(Data[row_2]); } } template < class T> void Matrix< T >::InterchangeCols(unsigned int col_1, unsigned int col_2) { // Parentheses for easier reading only // Make sure both columns are different and range in [0, Cols[ if((col_1 != col_2) && (col_1 >= 0) && (col_2 >= 0) && (col_1 < Cols) && (col_2 < Cols)) { for(int j = 0; j < Rows; j++) { T tmp = Data[j][col_1]; Data[j][col_1] = Data[j][col_2]; Data[j][col_2] = tmp; } } } template < class T > bool Matrix< T >::LowerTriangle( ) const { // Only square matrixes bigger than 0,0 if(SquareMatrix() && (Cols != 0 && Rows != 0)) { for(int j = 0; j < Rows; j++) { for(int i = 0; i < Cols; i++) { if(i > j && Data[j][i] != 0) { return false; } } } } else { return false; } return true; } template < class T > bool Matrix< T >::UpperTriangle( ) const { // Only square matrixes bigger than 0,0 if(SquareMatrix() && (Cols != 0 && Rows != 0)) { for(int j = 0; j < Rows; j++) { for(int i = 0; i < Cols; i++) { if(i < j && Data[j][i] != 0) { return false; } } } } else { return false; } return true; } template < class T > bool Matrix< T >::SquareMatrix( ) const { return (Rows == Cols); } template < class T > T Matrix< T >::Determinant( ) { if(SquareMatrix( )) { if(Cols == 0 && Rows == 0) { return static_cast< T >(0); } if(Cols == 1 && Rows == 1) { return Data[0][0]; } if(UpperTriangle( ) || LowerTriangle( )) { int total = 1; for(int i = 0; i < Cols; i++) { total *= Data[i][i]; } return total; } if(Cols == 2 && Rows == 2) { return (Data[0][0] * Data[1][1] - Data[0][1] * Data[1][0]); } if(Cols == 3 && Rows == 3) { return (Data[0][0] * Data[1][1] * Data[2][2] + Data[0][2] * Data[1][0] * Data[2][1] + Data[0][1] * Data[1][2] * Data[2][0] - Data[0][2] * Data[1][1] * Data[2][0] - Data[0][0] * Data[1][2] * Data[2][1] - Data[0][1] * Data[1][0] * Data[2][2]); } // Let's use the M = LU decomposition method for faster processing else { } } } template < class T > typename Matrix< T >::MATRIX_PTR Matrix< T >::IdentityMatrix(unsigned int size) { MATRIX_PTR tmp(new Matrix< T >(size, size)); for(int j = 0; j < tmp->Rows; j++) { for(int i = 0; i < tmp->Cols; i++) { tmp->Data[j][i] = i == j ? 1 : 0; } } return tmp; } template < class T > typename Matrix< T >::MATRIX_PTR Matrix< T >::NullMatrix(unsigned int size) { return MATRIX_PTR(new Matrix< T >(size, size)); } template < class T > typename Matrix< T >::MATRIX_PTR Matrix< T >::Minor(unsigned int col, unsigned int row) { static MATRIX_PTR tmp; if(SquareMatrix( ) && (Rows != 0 && Cols != 0)) { tmp.reset(new Matrix< T >); int y = 0; // Move horizontally then down in the matrix for(int j = 0; j < Rows; j++) { if(j != row) { // We're on a new line... tmp->Data.push_back(std::vector< T >( )); for(int i = 0; i < Cols; i++) { if(i != col) { (tmp->Data[y]).push_back(Data[j][i]); } } y++; } } tmp->Cols = tmp->Data[0].size(); tmp->Rows = tmp->Data.size(); } return tmp; } template< class T > Matrix< T >& Matrix< T >::operator = (const Matrix< T >& m) { Rows = m.Rows; Cols = m.Cols; Data.assign(m.Data.begin(), m.Data.end()); return *this; } template< class T > Matrix< T >& Matrix< T >::operator += (const Matrix< T >& m) { *this = *this + m; return *this; } template< class T > Matrix< T >& Matrix< T >::operator -= (const Matrix< T >& m) { *this = *this - m; return *this; } template< class T > Matrix< T > Matrix< T >::operator * (const Matrix< T >& m) const { // A Matrix A(a, b) and a matrix B(c, d) yield a matric C(b, c) when multiplied Matrix< T > tmp(Rows, m.Cols); if(Cols == m.Rows && Rows == m.Cols && Rows > 0 && Cols > 0) { for(int j_result = 0; j_result < Rows; j_result++) { for(int i_result = 0; i_result < m.Cols; i_result++) { int sum = 0; for(int j = 0, i = 0; j < m.Rows && i < Cols; j++, i++) { sum += Data[j_result][i] * m.Data[j][i_result]; } tmp.Data[j_result][i_result] = sum; } } } return tmp; } template< class T > Matrix< T > Matrix< T >::operator - (const Matrix< T >& m) const { Matrix< T > tmp(Cols, Rows); if(Rows == m.Rows && Cols == m.Cols && Rows > 0 && Cols > 0) { for(int j = 0; j < Rows; j++) { for(int i = 0; i < Cols; i++) { tmp.Data[j][i] = Data[j][i] - m.Data[j][i]; } } } return tmp; } template< class T > Matrix< T > Matrix< T >::operator + (const Matrix< T >& m) const { Matrix< T > tmp(Cols, Rows); if(Rows == m.Rows && Cols == m.Cols && Rows > 0 && Cols > 0) { for(int j = 0; j < Rows; j++) { for(int i = 0; i < Cols; i++) { tmp.Data[j][i] = Data[j][i] + m.Data[j][i]; } } } return tmp; } #endif // MATRIX_H_INCLUDED
