Dropping Support for AoS

[ax3l]

Hi everyone,

I am highly inclined to drop support for the legacy AoS particle structure in pyAMReX, because it is:

• hard to maintain
• slow
• superseded by the way faster pure SoA particle layout
• cannot support the same Python features anyway, e.g., cupy has no struct support yet.

Does anyone have a strong use case to still support it in pyAMReX (i.e., is there a strong use case not to transition to pureSoA in your code and still using pyAMReX)?