class_VectorBlock.cpp revision c981c48f5bc9aefeffc0bcb0cc3934c2fae179dd 
1#include <Eigen/Core>
2#include <iostream>
3using namespace Eigen;
4using namespace std;
5
6template<typename Derived>
7Eigen::VectorBlock<Derived>
8segmentFromRange(MatrixBase<Derived>& v, int start, int end)
9{
10  return Eigen::VectorBlock<Derived>(v.derived(), start, end-start);
11}
12
13template<typename Derived>
14const Eigen::VectorBlock<const Derived>
15segmentFromRange(const MatrixBase<Derived>& v, int start, int end)
16{
17  return Eigen::VectorBlock<const Derived>(v.derived(), start, end-start);
18}
19
20int main(int, char**)
21{
22  Matrix<int,1,6> v; v << 1,2,3,4,5,6;
23  cout << segmentFromRange(2*v, 2, 4) << endl; // calls the const version
24  segmentFromRange(v, 1, 3) *= 5;              // calls the non-const version
25  cout << "Now the vector v is:" << endl << v << endl;
26  return 0;
27}
28