Implementing PAW (projector augmented wave)

[wenfei-li]

Background

ABINIT has a very nice PAW module which can be adopted for carrying out PAW calculations.

Describe the solution you'd like

I am currently working on it.

Additional Context

No response

[wenfei-li]

#2633 the first pr; deals with some basic reading operations and spherical bessel transformation

[wenfei-li]

#2694 the second pr; deals with splines and spherical harmonics

[wenfei-li]

#2731 the third pr, added paw_atom class

[wenfei-li]

#2734 calculates rhoij from wavefunctions

[wenfei-li]

#2815 some subroutines for collecting and passing information to libpaw

[hongriTianqi]

• Review and understand the proposed feature and its importance.
• Research on the existing solutions and relevant research articles/resources.
• Discuss with the team to evaluate the feasibility of implementing the feature.
• Create a design document outlining the proposed solution and implementation details.
• Get feedback from the team on the design document.
• Develop the feature following the agreed design.
• Write unit tests and integration tests for the feature.
• Update the documentation to include the new feature.
• Perform code review and address any issues.
• Merge the feature into the main branch.
• Monitor for any issues or bugs reported by users after the feature is released.
• Address any issues or bugs reported by users and continuously improve the feature.

[wenfei-li]

I will close this issue with #3110, which fixes the last bug for multi-k paw. Now PAW works for SCF calculations.