How to obtain the Jacobian matrix?

Hi, all!

I want to do inversion by myself through SimPEG, so I need the Jacobian matrix. Does anyone know how to obtain the Jacobian matrix in SimPEG.

Thanks!
Hang

Hi @geohang ,
The Jacobian is not often formed as it gets bigs very quickly. I believe it can only be explicitly formed for potential fields (mag and grav.) and DC (if you set the option storeJ=True). In those cases, you can access the Jacobian via the simulation object: simulation.G

1 Like

Hi Thibaut,
could you please give an example code? Of course for inversion the Jacobian is rarely formed explicitly, as you only need it within matrix-vector-products which can be calculated much faster and without storing. However, it is often useful for understanding the inversion, e.g. when calculating sensitivities or other uncertainty/resolution indicators, or for running a nullspace shuttle.
Cheers,
Volker