class_FixedBlock.cpp
No OneTemporary
Actions

Subscribers

None

File Metadata

	#include <Eigen/Core>
	#include <iostream>
	using namespace Eigen;
	using namespace std;

	template<typename Derived>
	Eigen::Block<Derived, 2, 2>
	topLeft2x2Corner(MatrixBase<Derived>& m)
	{
	return Eigen::Block<Derived, 2, 2>(m.derived(), 0, 0);
	}

	template<typename Derived>
	const Eigen::Block<const Derived, 2, 2>
	topLeft2x2Corner(const MatrixBase<Derived>& m)
	{
	return Eigen::Block<const Derived, 2, 2>(m.derived(), 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;
	}