Real-space position operator matrix elements between different cell

[ryotaono10]

Dear Wannier.jl developers,

I am trying to obtain real-space position operator matrix elements
between the WFs of different cells, e.g. <0n|r|Rm>.
I checked position_op, but it seems it does only within the home unit cell <0n|r|0m>.
Is it possible to obtain <0n|r|Rm> by this function?
If it is not implemented yet, it would be not so difficult as it simply needs to shift the
Wannier functions and compute position_op. This would be very useful to have it.
For example, I needed to use very dense k-points to obtain reasonable position matrix in
wannier90 because of the formula it uses (derivative on k-mesh).
Also, if there is a way to control density of real-space mesh of WFs, I think it would be great.

Best regards,
Ryota