Finite Difference Gradients

[gustavojra]

Highly desired features that we must implement asap. This would be the easiest type of gradients since it is independent on the method.

• Serial
• Parallel

For the serial approach we can easily employ the orbitals and amplitudes from the reference structure as initial guess. For parallel we need to figure out how to make this info available (Since parallel in this case means basically generating inputs for individual computations).

A more involved approach for the Parallel gradient would be exploring Distributed.jl.

[cortner]

Can I ask what the general status is here on FD gradients in particular, but gradients in general?

CC @DexuanZhou