Does AMReX provide a piecewise constant cell-centered interpolater?

[Afraid31]

Hi all,

I'm working with AMReX in 2D using cell-centered data, and I'm using FillPatchTwoLevels to interpolate data from coarse to fine levels. By default, I understand that cell_cons_interp uses linear conservative interpolation (i.e., CellConservativeLinear), which averages surrounding coarse cells.

However, in my case I just want a simple piecewise constant interpolation, where each fine cell simply copies the value from its corresponding coarse cell (i.e., no interpolation, just duplication of the coarse value).

My questions are:

Does AMReX already provide a built-in piecewise constant interpolater for cell-centered data?

If not, what is the recommended way to implement such an interpolater in AMReX? Do I need to subclass amrex::Interpolater myself?

Any minimal example or pointers to relevant documentation would be much appreciated!

Thanks!

[WeiqunZhang]

You can use pc_interp, which does piecewise constant interpolation on cell centered data.

amrex/Src/AmrCore/AMReX_Interpolater.H

Line 446 in 65bf80d

* \brief Piecewise Constant interpolation on cell centered data.

[Afraid31]

Thanks a lot! That’s exactly what I needed.
I wasn’t aware that pc_interp was already available in AMReX—this makes things much simpler.
Appreciate the clear explanation and pointer!