making use of data.table GFORCE optimizations

[myoung3]

lapply(.SD) do optimizations work within a compound (ie multi-line) j statement?
right now it's a for loop so this isn't making use of the optimization level 1.
https://www.rdocumentation.org/packages/data.table/versions/1.12.2/topics/datatable.optimize

to achieve optimization level 2, use prod() instead of "/"

[myoung3]

read: Rdatatable/data.table#1414
especially: https://www.brodieg.com/2019/02/24/a-strategy-for-faster-group-statisitics/#blood-from-a-turnip

[myoung3]

It looks like it's easiest just to use eval(parse(text=