RE: Portland Group f77 compiler

From: "Bachman, William" Subject:RE: [NMusers] Portland Group f77 compiler Date:Tue, 6 Aug 2002 09:03:17 -0400 Nick, You can't just leave it at that. What evidence do you have to support this claim: "I know from testing under Windows that the Compaq Visual Fortran compiler (v 6.6A) appears to be numerically more robust than g77." My experience has been to the contrary, the g77 compiler (with -O optimization) behaved better with respect to floating point runtime errors than the Compaq/Digital (with "/optimize:1 /fpe:0" optimization" which has been used widely as the default). The results produced have been consistant with output produced on UNIX systems using either g77 or Sun's compiler. (A "better" (more robust) set of optimization options for Compaq/Digital seems to be "/optimize:4 /fltconsistency /fpe:3" with respect to floating point operations.) regards, Bill