work around apparent matrix_product bug
work around apparent matrix_product bug

aleksandr-bakanov/astropy,mhvk/astropy,bsipocz/astropy,aleksandr-bakanov/astropy,astropy/astropy,stargaser/astropy,kelle/astropy,aleksandr-bakanov/astropy,dhomeier/astropy,pllim/astropy,saimn/astropy,aleksandr-bakanov/astropy,pllim/astropy,AustereCuriosity/astropy,AustereCuriosity/astropy,funbaker/astropy,kelle/astropy,DougBurke/astropy,saimn/astropy,StuartLittlefair/astropy,MSeifert04/astropy,larrybradley/astropy,larrybradley/astropy,MSeifert04/astropy,saimn/astropy,stargaser/astropy,mhvk/astropy,pllim/astropy,astropy/astropy,kelle/astropy,dhomeier/astropy,astropy/astropy,funbaker/astropy,bsipocz/astropy,DougBurke/astropy,DougBurke/astropy,larrybradley/astropy,saimn/astropy,lpsinger/astropy,dhomeier/astropy,astropy/astropy,StuartLittlefair/astropy,kelle/astropy,mhvk/astropy,lpsinger/astropy,larrybradley/astropy,bsipocz/astropy,stargaser/astropy,mhvk/astropy,AustereCuriosity/astropy,StuartLittlefair/astropy,lpsinger/astropy,stargaser/astropy,funbaker/astropy,AustereCuriosity/astropy,pllim/astropy,lpsinger/astropy,larrybradley/astropy,funbaker/astropy,astropy/astropy,lpsinger/astropy,MSeifert04/astropy,bsipocz/astropy,StuartLittlefair/astropy,mhvk/astropy,MSeifert04/astropy,pllim/astropy,kelle/astropy,AustereCuriosity/astropy,dhomeier/astropy,DougBurke/astropy,dhomeier/astropy,StuartLittlefair/astropy,saimn/astropy