from_rotation_matrix

kyosu::from_rotation_matrix = eve::functor<from_rotation_matrix_t>

inlineconstexpr

Callable object computing a quaternion from its rotation_matrix representation.

This function returns a quaternion associated to the input rotation matrix m. If m is not a proper 3x3 rotation matrix (i.e an orthogonal matrix with determinant 1) the result is undefined.

Header file

#include kyosu/quaternion.hpp>`

Callable Signatures

namespace eve
{
   template < typename M >
   auto from_rotation_matrix(auto m) const noexcept
}

Parameters

• m the rotation matrix. The actual implementation assumes that m[i][j] will return the ith line and jth column element of the matrix (indices starting from 0).

  The computation method is inspired from the article: "Accurate Computation of Quaternions from Rotation Matrices", by Soheil Sarabandi and Federico Thomas Institut de Robotica i Informatica Industrial (CSIC-UPC) Llorens Artigas 4-6, 08028 Barcelona, Spain.

Return value

an unitary quaternion representing the rotation

Example

#include <kyosu/kyosu.hpp>
#include <eve/wide.hpp>
#include <iostream>
 
int main()
{
  using kyosu::to_rotation_matrix;
  using kyosu::from_rotation_matrix;
  using kyosu::complex_t;
  using kyosu::quaternion_t;
  using q_t = kyosu::quaternion_t<float>;
 
 
  std::cout << "Quaternion:  "<< "\n";
  q_t q0(1, 5, 2, 3);
  q0 = kyosu::sign(q0); //normalization is optional
  auto m = to_rotation_matrix(q0);
  std::cout << "q0 =  " << q0 << std::endl;
  std::cout << "m = to_rotation_matrix(q0) = \n";
  for(int i=0; i <3 ; ++i)
  {
    std::cout << "    ";
    for(int j=0; j < 2 ; ++j)
    {
      std::cout << m[i][j] << ", ";
    }
    std::cout << m[i][2] << "\n";
  }
  std::cout << "from_rotation_matrix(m) =  " << from_rotation_matrix(m) << std::endl;
 
  return 0;
}