f: Food
Variable
Agricultural sector
Food [Veg eq kg/year]
f = ly * al * lfh *(1- pl )

f in the updating graph: ( how to read )
In nodes
al : Arable Land
lfh : land fraction harvested
ly : land yield
pl : processing loss
Out nodes
fao : fraction of output in agriculture
foi : fraction of output in industry
fos : fraction of output in services
fpc : food per capita