demands for TI with temperature/pressure-dependent constrains

[Vibsteamer]

Dear developers,

Here comes a demand to conduct TI with temperature/pressure-dependent constrains.

The scenario is to obtain the temperature-dependent Free energy difference as [ΔG = G2-(G0+G1)] vs T，
where sys2 and sys1 at each temperature point is compressed/stretched by the box of sys0 at the corresponding temperature, (use y and z box-vectors of sys0 at different temperatures as the constrains, meanwhile allow the x direction to relax)

In implementation, the high-T cases can not be handled by HTI due to the high-T jump out of the string-well for the equi_position
thus it should be implemented by the TI path

however,
current TI path doesn't support the
1) integration-condition(T/P)-specific control of the variables,
in this case, box vectors in the structure file
2) output the MD-averaged structure at each TI simulation point
in this case, box vectors of sys0 is the prerequisite for setting TI parameters for sys1 and sys2

Can these two specific requests be satisfied?

Looking forwards to the development, similar demands may present in many practical simulations in fields of material sciences.

3. btw, the MD ensemble setting in lammps (fix npt ... ... x ... ... ) to allow specific constrains in MD is currently implemented by hacking the code
   It's also expecting an official patch to permits more kinds of constrains allowed in fix/npt command of lammps.

[wanghan-iapcm]

@felix5572 Could you please take a look? Thanks!

[Vibsteamer]

A workaround was attempted without further hacking the code,
by manually pausing then continuing the workflow, and replacing input files in corresponding folder.

Best wishes to your endeavor~