Thank you Tejal, I appreciate it. It’s not as straightforward indeed with reverse mode. I am going to right one, just to find some time ! In the meantime you can take a look at this code I published on GitHub a while ago :

OmarAflak/autodiff

It’s not a very efficient implementation to be honest and it’s not a minimal working code so it might be a bit complicated to understand, but still. You can also subscribe to my account, you’ll get a notification when I publish the article. Thanks !