output.log

[[email protected] saurabh]$ g++ -std=c++14 -O3 -w eigen_sqrt.cpp -I/usr/include/eigen3
[[email protected] saurabh]$ ./a.out
default ctor called.
default ctor called.
default ctor called.
default ctor called.
default ctor called.
default ctor called.
Task 1
initializer ctor called.
assignment operator called.
initializer ctor called.
assignment operator called.
initializer ctor called.
assignment operator called.
initializer ctor called.
assignment operator called.
initializer ctor called.
assignment operator called.
initializer ctor called.
assignment operator called.
default ctor called.
default ctor called.
default ctor called.
default ctor called.
default ctor called.
default ctor called.
assignment operator called.
assignment operator called.
assignment operator called.
assignment operator called.
assignment operator called.
assignment operator called.
0 0 0
0 0 0

tmp_memalloc_eigen.cpp

#include <iostream>
#include <memory>
#include <Eigen/Eigen>

using std::cout;
using std::endl;
using std::make_unique;
using std::unique_ptr;
using Eigen::Matrix;
using Eigen::Dynamic;
using Eigen::Map;

template <typename T>
struct Type
{
	Type() : _value(static_cast<T>(0)) { cout << "default ctor called." << endl; }
	Type(T value) : _value(value) { cout << "initializer ctor called." << endl; }
	Type(const Type& other) : _value(other._value) { cout << "copy ctor called." << endl; }
	Type& operator=(const Type& other)
	{
		_value = other._value;
		cout << "assignment operator called." << endl;
		return *this;
	}
	operator T()
	{
		return _value;
	}
	operator const T() const
	{
		return _value;
	}
	T _value;
};

int main()
{
	auto mapped_mem = make_unique<Type<double>[]>(2*3);
	Map<Matrix<Type<double>, Dynamic, Dynamic>> map(mapped_mem.get(), 2, 3);
	cout << "Task 1" << endl;
	map = map.array().sqrt();
	cout << map << endl;
	return 0;
}