It seems like all caching data from
Subprogramm is purged after closing a file, but can we re-use this internal cache?
I was thinking about running few instances of Blender to write
Subprogramm Loop cache on different frames simultaneously and then save it for further use. Mainly to speed up the process, as AN doesn't use all CPU power.
P.S. Right now I am saving OBJ sequences splitted between two instances of Blender and converting it to Alembic, which is quite annoying.
EDIT: Trying to implement Omar's solution...
Cube is simply rotating at (0,0,0). I am caching vertices and writing them to dynamic keys. After disconnecting
Subprogram from upper
Expression I can keep data for 1 full animation timeline. When I want to repeat animation - all data is lost.