[Feature Request] Support "direct_force" and "direct_force_ener" fitting type in Pytorch code

[Chengqian-Zhang]

Summary

Support "direct_force" and "direct_force_ener" fitting type in Pytorch code

Detailed Description

I find that when I add key in model/fitting: "type": "direct_force" or "direct_force_ener". It occurs an error:

Further Information, Files, and Links

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