The walking model SLvsLL defines a UE walking in a straight line. It was created with the purpose of comparing our link-level with the system-level simulator, and using very specific scenarios, as you can see from the values there.
With the SLvsLL waling model, after defining the distances vector for the positions we want to move the UE along this stright line, it generates the new position by counting the number of elements of the distance vector. It doesn’t return the same value.
If you are getting the same position, then the UE is not moving, please check the parameter LTE_config.keep_UEs_still = true/false; (true: UE doesn’t move).