docs: def dcmtoquat(dcm):
      """Convert DCM to quaternion
      
      This function will convert a rotation matrix, also called a direction
      cosine matrix into the equivalent quaternion.
  
      Parameters:
      ----------
      dcm - (3,3) numpy array
          Numpy rotation matrix which defines a rotation from the b to a frame
  
      Returns:
      --------
      quat - (4,) numpy array
          Array defining a quaterion where the quaternion is defined in terms of
          a vector and a scalar part.  The vector is related to the eigen axis
          and equivalent in both reference frames [x y z w]
      """
      quat = np.zeros(4)
      quat[-1] = 1/2*np.sqrt(np.trace(dcm)+1)
      quat[0:3] = 1/4/quat[-1]*vee_map(dcm-dcm.T)
  
      return quat