How to get the physical coordinates in the tile-box?

[Horizonatpku]

Hi everyone,

I want to use the physical coordinates in the tile-box (mfi%tilebox) to participate the calculation.

However, I don't know how to get the physical coordinates in the tile-box and even the grid-space of the tile-box (dx, dy, dz).

I will be appreciate if someone can give me some help!

Best wishes,

He Yifeng

[atmyers]

The information needed to map between index-space and physical space coordinates, including the cell spacing and global domain offset, is stored in the amrex::Geometry object. You need to query that. You may find this function in WarpX helpful: https://github.com/ECP-WarpX/WarpX/blob/development/Source/WarpX.cpp#L2296

[Horizonatpku]

Hi Myers,

Thank you for you nice advice!

I am not familiar with AMRex, I do not know if I understand the code you point out

For example in Fortran codes, I get a tilebox named tbx and it is located in the level named lev

First, I announce geom :

type(amrex_geometry) :: geom

then get the specific geom for tbx

gm = GetInstance().Geom(lev)

Finally, I can get the cell spacing and physical lower bounds of tbx

dx=gm.CellSize()
lowbd=gm.ProbLo()

I will be appreciate if you can give me some suggestions, thank u again!

Best wishes,
He Yifeng

[atmyers]

If you are using the Fortran Interfaces, you'll need to use the methods here instead of the C++ versions: https://github.com/AMReX-Codes/amrex/blob/development/Src/F_Interfaces/Base/AMReX_geometry_mod.F90

In that case, there is also a geom%get_physical_location method that you could use on tbx%lo and tbx%hi.