updated to handle (-)ve margin for surface shrinkage
updated to handle (-)ve margin for surface shrinkage

cerr/CERR,cerr/CERR,aditiiyer/CERR,aditiiyer/CERR,cerr/CERR,cerr/CERR,aditiiyer/CERR,cerr/CERR,aditiiyer/CERR,cerr/CERR,aditiiyer/CERR,cerr/CERR,cerr/CERR,aditiiyer/CERR,cerr/CERR,aditiiyer/CERR,aditiiyer/CERR