Extruding 2-d checkpoint data to 3-d

[RSuryaNarayan]

Hello everyone,

Is there a way to read a 2-D checkpoint and convert it into a 3-D checkpoint by extruding it uniformly along the third direction?

Thanks a lot.

[WeiqunZhang]

Could you be more specific about the format of your checkpoint files? The 2D MultiFab data written with 2D VisMF::Write can be read with 3D `VisMF::Read. The result will be a 3D MulitFab with one cell and zero ghost cells in the z-direction. One can then write a function to extend the data to 3d. We will show you how to do this later. But the first thing it to read the data.

[RSuryaNarayan]

Hello, a follow up on this. If I were to do this on a plotfile instead (i.e. take a 2-D plotfile and just convert it to 3D with one cell along the third direction), could I still use VisMF::Read()?

[drummerdoc]

The plot files are read with VisMF::Read, or you can manually read them directly. There are several pieces of data in the plot file Header (ascii) files that are 2D specific, so to read a 2D plot file with a code compiled for 3D, you'd have to manually edit the corresponding fields in the Header.

Your question here is a little ill-formed though. Can you rephrase?

[RSuryaNarayan]

@drummerdoc basically I'm looking for a standalone AMReX script that takes in 2D plotfile data and just extrudes it to 3D (with only 1 cell along the third direction). Specifically, I'd be using Pele plotfiles.

Basically trying to hack my way through to circumvent the 2D specific problem that arises when I try to run AmrDeriveSpectrum

[WeiqunZhang]

You can read a 2d plotfile with PlotFileData in an executable compiled for 3d. The class in AMReX_PlotFileUtil.H. Once you have the data and meta-data in memory, you can write out a true 3d plotfile if you want.

[RSuryaNarayan]

@WeiqunZhang Thanks. So basically I compile in 3D but using generic, dimension agnostic readers inside the script. Is that correct?

[WeiqunZhang]

Right. The reader is dimension agnostic if it's compiled in 3d. If the reader is compiled in 2d, it won't read 3d data.

[RSuryaNarayan]

@WeiqunZhang thanks. Could you point me to the exact function that does the readimg?

[drummerdoc]

PlotFileData::get() in AMReX_PlotFileUtil.H

[RSuryaNarayan]

thanks! @drummerdoc

[RSuryaNarayan]

Thanks for the inputs @drummerdoc and @WeiqunZhang I finally wrote some code that works. Posting it for the benefit of other users: https://github.com/RSuryaNarayan/AMReX-Pseduo3D which does the job