c++ Matrix with Expression template issues - c++

Question

I have to make a school project, which work with matrices. In Visual Studio 2010 everything works fine. The tester server have the "matrix_base" and the main function, for example:
template<class T, int N, int M, class LeftOp, class RightOp> class my_matrixAdd;
template<class T, int N, int M, class LeftOp, class RightOp> class my_matrixSub;
template<class T, int N, int M, class LeftOp, class RightOp> class my_matrixMul;
template<class T, int N, int M>
class my_matrix //: matrix_base
{
private:
T arrData[N][M];
int columns;
int rows;
public:
my_matrix() : columns(N), rows(M) {}
template<class LeftOp, class RightOp>
my_matrix<T, N, M> & operator=(
const my_matrixAdd<T, N, M, LeftOp, RightOp> & mx)
{
for(int i=0; i<N; ++i)
for(int j=0; j<M; ++j)
{
At(i, j) = mx.At(i, j);
}
return *this;
}
template<class LeftOp, class RightOp>
my_matrix<T, N, M> & operator=(
const my_matrixMul<T, N, M, LeftOp, RightOp> & mx)
{
for(int i=0; i<N; ++i)
for(int j=0; j<M; ++j)
{
At(i, j) = mx.At(i, j);
}
return *this;
}
template<class LeftOp, class RightOp>
my_matrix<T, N, M> & operator=(
const my_matrixSub<T, N, M, LeftOp, RightOp> & mx)
{
for(int i=0; i<N; ++i)
for(int j=0; j<M; ++j)
{
At(i, j) = mx.At(i, j);
}
return *this;
}
virtual ~my_matrix() {}
const T& At(int n, int m) const
{
return arrData[n][m];
}
T& At(int n, int m)
{
return arrData[n][m];
}
const T& operator()(int n, int m) const
{
return arrData[n][m];
};
T& operator()(int n, int m)
{
return arrData[n][m];
};
int Columns() const { return columns; }
int Rows() const { return rows; }
};
template< class T, int N, int M, class LeftOp, class RightOp>
class my_matrixAdd
{
private:
const LeftOp& m_lhs;
const RightOp& m_rhs;
public:
my_matrixAdd(
const LeftOp& lhs, const RightOp& rhs) :
m_lhs(lhs), m_rhs(rhs) {}
T At(int x, int y) const
{
return m_lhs.At(x, y) + m_rhs.At(x, y);
}
};
template<class T, int N, int M>
inline my_matrixAdd<T, N, M, my_matrix<T, N, M> , my_matrix<T, N, M> >
operator+(const my_matrix<T, N, M> &l, const my_matrix<T, N, M> &r)
{
return my_matrixAdd<T, N, M, my_matrix<T, N, M> ,
my_matrix<T, N, M> > (l, r);
}
template<class T, int N, int M, class LeftOp, class RightOp>
inline my_matrixAdd<T, N, M, my_matrixAdd<T, N, M, LeftOp, RightOp> ,
my_matrix<T, N, M> >
operator+(const my_matrixAdd<T, N, M, LeftOp, RightOp> &l,
const my_matrix<T, N, M> &r)
{
return my_matrixAdd<T, N, M, my_matrixAdd<T, N, M, LeftOp, RightOp> ,
my_matrix<T, N, M> > (l, r);
}
template<class T, int N, int M, class LeftOp, class RightOp>
inline my_matrixAdd<T, N, M, my_matrixSub<T, N, M, LeftOp, RightOp> ,
my_matrix<T, N, M> >
operator+(const my_matrixSub<T, N, M, LeftOp, RightOp> &l,
const my_matrix<T, N, M> &r)
{
return my_matrixAdd<T, N, M, my_matrixSub<T, N, M, LeftOp, RightOp> ,
my_matrix<T, N, M> > (l, r);
}
int main()
{
my_matrix<int,2,2> mtx1;
my_matrix<int,2,2> mtx2;
my_matrix<int,2,2> mtx3;
my_matrix<int,2,2> mtx4;
mtx4 = mtx1 + mtx2 + mtx3;
return 0;
}
The compiler in the server is a g++ with -static -O2 parameters.
And i get errors like:
/var/www/F/I704e/3/1/teszt1.cpp: In function ‘int main()’:
/var/www/F/I704e/3/1/teszt1.cpp:42: error: no match for ‘operator+’ in ‘operator+(const my_matrix&, const my_matrixAdd&) [with T = int, int N = 5, int M = 3, LeftOp = my_matrix, RightOp = my_matrix](((const my_matrixAdd, my_matrix >&)((const my_matrixAdd, my_matrix >*)(& operator+(const my_matrix&, const my_matrix&) [with T = int, int N = 5, int M = 3](((const my_matrix&)((const my_matrix*)(& mtx3)))))))) + operator+(const my_matrixAdd&, const my_matrix&) [with T = int, int N = 5, int M = 3, LeftOp = my_matrix, RightOp = my_matrix](((const my_matrix&)((const my_matrix*)(& mtx6))))’
And like:
In file included from /var/www/F/I704e/3/1/teszt1.cpp:6:
/var/www/Hallg/I704e/3/h145172/7/feladat.cpp: In function ‘my_matrixAdd, my_matrixAdd > operator+(const my_matrixAdd&, const my_matrixAdd&) [with T = int, int N = 5, int M = 3, LeftOp = my_matrix, RightOp = my_matrix]’:
Please help me! Thank You!

Answer 1

This is an extended comment.
Here is my stripping of all of the unrequired stuff in your question:
template<class LeftOp, class RightOp>
class my_matrixAdd;
struct matrix_base {};
class my_matrix : matrix_base
{
public:
my_matrix() {}
template<class LeftOp, class RightOp>
my_matrix & operator=(const my_matrixAdd<LeftOp, RightOp> & mx) {
return *this;
}
virtual ~my_matrix() {}
};
template< class LeftOp, class RightOp>
class my_matrixAdd
{
private:
const LeftOp& m_lhs;
const RightOp& m_rhs;
public:
my_matrixAdd(const LeftOp& lhs, const RightOp& rhs) : m_lhs(lhs), m_rhs(rhs) {}
};
inline my_matrixAdd<my_matrix , my_matrix >
operator+(const my_matrix &l, const my_matrix &r) {
return my_matrixAdd<my_matrix, my_matrix > (l, r);
}
template<class LeftOp, class RightOp>
inline my_matrixAdd<my_matrixAdd<LeftOp, RightOp> , my_matrix >
operator+(const my_matrixAdd<LeftOp, RightOp> &l, const my_matrix &r) {
return my_matrixAdd<my_matrixAdd<LeftOp, RightOp>, my_matrix>(l, r);
}
#include <utility>
int main() {
my_matrix mtx1;
my_matrix mtx2;
my_matrix mtx3;
my_matrix mtx4;
// really, we should figure out what type these are explicitly, instead of using auto:
auto&& tmp1 = mtx1 + mtx2;
auto&& tmp2 = std::move(tmp1) + mtx3;
mtx4 = std::move(tmp2);
auto&& tmp3 = mtx2 + mtx3;
auto&& tmp4 = mtx1 + std::move(tmp3);
mtx4 = std::move(tmp4);
return 0;
}
note that this version also fails to compile. The reason is more obvious, however.
You should strip your code down to something like this, either ask for help understanding why there is still an error, fix it (or note that there is no longer a problem), then build it back up one step at a time.
You'll note that the classes don't do anything anymore -- which is good, because a type error isn't caused by what distant code does. (at worst, it is caused by their signature, which I left unchanged).