No need to double post. What happened was you meant to post in Help on Lotka Voltera model Parameter Estimation - #6 by ChrisRackauckas, but it seems you posted in the wrong thread (Please read: make it easier to help you - #112 by Miraj_Miraj) so your response wasn’t seen. I commented on the original thread to get this going. Though please follow the guidelines of Please read: make it easier to help you and share the code that you ran, as otherwise we do not know what exactly you ran!