eigen/doc/examples/class_FixedBlock.cpp
Benoit Jacob 01572b9f54 big change: MatrixBase only takes one template parameter "Derived", the
template parameter "Scalar" is removed. This is achieved by introducting a
template <typename Derived> struct Scalar to achieve a forward-declaration of
the Scalar typedefs.
2008-03-10 17:23:11 +00:00

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C++

#include <Eigen/Core>
USING_PART_OF_NAMESPACE_EIGEN
using namespace std;
template<typename Derived>
Eigen::Block<Derived, 2, 2>
topLeft2x2Corner(MatrixBase<Derived>& m)
{
return Eigen::Block<Derived, 2, 2>(m.asArg(), 0, 0);
}
template<typename Derived>
const Eigen::Block<Derived, 2, 2>
topLeft2x2Corner(const MatrixBase<Derived>& m)
{
return Eigen::Block<Derived, 2, 2>(m.asArg(), 0, 0);
}
int main(int, char**)
{
Matrix3d m = Matrix3d::identity();
cout << topLeft2x2Corner(4*m) << endl; // calls the const version
topLeft2x2Corner(m) *= 2; // calls the non-const version
cout << "Now the matrix m is:" << endl << m << endl;
return 0;
}