Draft: Implement jacobian
What does the code in the MR do ?
Right now it simply reimplements the jacobian/gradient of the model, it should (soon) work with the personalization option using the jacobian to optimize the scipy.minimize
Where should the reviewer start ?
Look at the implementation of the jacobian in multivariate model.
How can the code be tested ?
Try a personalization with jacobian.
When is the MR due for? (review deadline)
End of sprint.