We’ve recently upgraded from pgi 6.0 to 6.1 on our Intel Xeon workstations. As noted in the release notes, we do see numerical differences in the output of programs as a result of the compiler upgrade. Adding the -Mnoscalarsse and removing the -O2 optimzation option does ellimate the numerical differences. However, removing optimization is not the ideal solution. Is there a set of compiler options that can be used in 6.1 to mimic -O2, while producing the same results as we would expect from PGI 6.0?