adding parts for intaking xsec; re-wrote run () s.t. it's easier to see what's going on
adding parts for intaking xsec; re-wrote run () s.t. it's easier
to see what's going on

weixiong-zheng-berkeley/BART,weixiong-zheng-berkeley/BART,jsrehak/BART,jsrehak/BART,weixiong-zheng-berkeley/BART