Feature: Charge/Wavefunction Extrapolation with External Interfaces

[QuantumMisaka]

Background

3264 is a start for external interfaces to use electronic structure information from ABACUS to do next ionic step, but only read-in the charge and wavefunction file for initialization of next ionic step is not enough, extrapolation for wavefunction & charge is needed when using external interface like ASE to do optimization, NEB or other jobs.

ABACUS have charge/wavefunction extrapolation now, the only thing is to use it.

Describe the solution you'd like

Modification of wavefunction and charge file read-in part and charge initialization part, which allows ABACUS to do extrapolation with read-in charge and wavefunction file from last ionic step and read-in STRU for next ionic step.

Task list only for developers

• [ ] Notice possible changes of behavior
• [ ] Explain the changes of codes in core modules of ESolver, HSolver, ElecState, Hamilt, Operator or Psi

Notice Possible Changes of Behavior (Reminder only for developers)

No response

Notice any changes of core modules (Reminder only for developers)

No response

Notice Possible Changes of Core Modules (Reminder only for developers)

No response

Additional Context

I'd like to make it my first contribution for ABACUS source code with some help.

Task list for Issue attackers (only for developers)

• [ ] 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.

[WHUweiqingzhou]

@QuantumMisaka , May I ask your further plan for this issue?