Gradient calculation of FWI using devito based on a new wave equation

[Ruihua-Chen]

Devito is a powerful open source program to implement the wave equation forward modeling and full waveform inverison. I am currently implementing FWI based on the immersive boundary method. Could you please tell me what modifications I need to make to the backpropagation module provided by Devito? Or like automatic differentiation, simply achieve forward modeling and thereby automatically perform backward propagation of gradient calculations?