On Fri, 2 Mar 2012, Jed Brown wrote: > On Fri, Mar 2, 2012 at 07:55, TAY wee-beng <zonexo at gmail.com> wrote: > > > May I know if it is advisable to use -ipo, -fast or -O3 during compilation > > of PETSc for the non debug mode? > > > > Will it be faster or will there be unpredictable errors? > > > > The only thing we can say for sure is that it will take longer to compile. > > (It may be faster or slower, probably not by much. There should not be > errors.)
The best way to see if it helps is to do a separate build of PETSc with these options - and compare -log_summary for runs with and without this option.. Note: Some compilers misbehave with '-fast' type options.. [not returing error codes - when there are compile errors]. When this happens - configure won't work properly.. Satish
