Small improvement in remapping

[AndyZe]

Resizing this output vector with every iteration isn't necessary.

The idea here is, make the variable static so it retains its value between iterations. Only remap if the dimension of the vector changes.

Partial fix to #392

[AndyZe]

If it's safe to assume dof_ never changes, this can get simpler.

dof_ changes here:

controller_interface::CallbackReturn JointTrajectoryController::on_configure(
  const rclcpp_lifecycle::State &)
{
  const auto logger = get_node()->get_logger();

  // update parameters
  joint_names_ = get_node()->get_parameter("joints").as_string_array();
  if ((dof_ > 0) && (joint_names_.size() != dof_))
  {
    RCLCPP_ERROR(
      logger,
      "The JointTrajectoryController does not support restarting with a different number of DOF");
    // TODO(andyz): update vector lengths if num. joints did change and re-initialize them so we
    // can continue
    return CallbackReturn::FAILURE;
  }

  dof_ = joint_names_.size();

So it could hypothetically change but that would be really unusual

[AndyZe]

I think it doesn't make any sense to allow dof_ to change since the yaml config file contains a list of joint names to control. Example config file here: https://github.com/ros-planning/moveit_resources/blob/ros2/panda_moveit_config/config/ros2_controllers.yaml

Agree, @destogl or @bmagyar ?

[destogl]

Yes! Please also see #394

[destogl]

I agree, although here it is not necessary to have great performance since this is (or at least should be) a non-realtime method.

[AndyZe]

well, this method is actually called in the update loop. I'll probably end up closing this PR if dof_ becomes constant because it won't be relevant anymore.