Combine the loops for masked and separately-weighted model sets. Avoid some extra transpositions.
Combine the loops for masked and separately-weighted model sets.
Avoid some extra transpositions.

aleksandr-bakanov/astropy,pllim/astropy,pllim/astropy,pllim/astropy,saimn/astropy,astropy/astropy,saimn/astropy,mhvk/astropy,saimn/astropy,astropy/astropy,dhomeier/astropy,dhomeier/astropy,astropy/astropy,larrybradley/astropy,lpsinger/astropy,saimn/astropy,larrybradley/astropy,mhvk/astropy,StuartLittlefair/astropy,mhvk/astropy,dhomeier/astropy,StuartLittlefair/astropy,pllim/astropy,lpsinger/astropy,lpsinger/astropy,larrybradley/astropy,saimn/astropy,StuartLittlefair/astropy,astropy/astropy,aleksandr-bakanov/astropy,pllim/astropy,mhvk/astropy,larrybradley/astropy,StuartLittlefair/astropy,larrybradley/astropy,lpsinger/astropy,mhvk/astropy,lpsinger/astropy,dhomeier/astropy,aleksandr-bakanov/astropy,aleksandr-bakanov/astropy,astropy/astropy,StuartLittlefair/astropy,dhomeier/astropy