Analytical Derivatives for ASCF

[nodeterz]

Hi,

Thank you for your great work on this project!

I was wondering if there are any plans to support analytical derivatives for ASCF.
I noticed there is a branch named acsf_grad, but it appears to encounter an issue related to NaNs in the G5 term.

I'd appreciate any updates or insights you could share on this.

Best regards,
Ehsan

[lauri-codes]

Hi @nodeterz!

At the moment, we do not have plans for this.

In principle lot of the scaffolding for doing this is in place: one would just need to implement the method derivatives_analytical in the ACSF class by following what has been done in the SOAP class and then ensuring that the implementation matches with the numerical derivatives with a unit test, as shown here for SOAP. If you would like to contribute this feature, we would be more than happy to accept it as a PR.