Downsampling: General Attributes

[ax3l]

For (field) data sets that were down-sampled, we could add that information so one can calculate the original grid spacing and size again that was used in the simulation.

Things that we have to make sure:

• down-sampling via striding or some kind of averaging (as an other attribute "...parameter")
• striding is also interesting for particle data (but a bit more dangerous due to internal data structures that might now represent a perfect statistical sample if strided)

[bussmann]

One should consider adding the down-sampling method as well.

[ax3l]

yes, that is the first point: methods could be simple striding or more sophisticated methods with various kinds of averaging.

[RemiLehe]

After discussing with @ax3l, it seems that we will defer this to the next version. The reason is that:

• down-sampled mesh can already be written in openPMD (one just has to take care of writing the gridSpacing correctly)
• for the moment there is no specific attribute that tags a mesh as downsampled, but one could indicate this in the comment attribute.

Adding a specific attribute will probably be done in the future, but I think we can skip it for the first release.