SST and SSC does not support Memory Selection in write side

[pnorbert]

We need SST and SSC support Memory Selection on the write side.

The Gray-Scott tutorial example is held back by the fact that only BP supports Memory Selection. We have been running the example with the old approach of double copy of data.

Example
https://github.com/ornladios/ADIOS2-Examples/tree/master/source/cpp/gray-scott

Set "adios_memory_selection": true, in input
https://github.com/ornladios/ADIOS2-Examples/blob/master/source/cpp/gray-scott/simulation/settings-files.json

gsplot.py will show that the data includes the ghost cells since memory selection is not executed.

[eisenhauer]

I think the question is: Are we happy with double copy (like we have in the BP5 file engine)? Or do we want to push the copy down into the serializer (actually into the MallocV buffer class) so that it only happens once? The former can happen immediately. WRT the latter, it might be the time to do it because we also need additional application-level information to handle GPU buffers for issue #3706 .

[pnorbert]

SST has had support for this for a while now, but SSC still doesn't