On IBM Power 6, which subrontines need the lowest optimization level?
Posted: Tue Oct 21, 2008 12:48 am
Hi All,
I tried to compile VASP on an IBM Power 6 system using the modifed makefile.rs6000 or makefile.sp2. The compilation has no problem. However, the calculated total energy is wrong when I use -O3 or -O2 opimization level to compile VASP. If the optimiztion level is downgraded to the lowest one (-O0), as expected, the calculated energy is correct. A similar problem was reported ealier: http://cms.mpi.univie.ac.at/vasp-forum/ ... php?2.4616
I think I have to use the lowest optimiztion level for certain subroutines. I tried to use -O0 for radial, nonl, nonlr, paw, pseudo, and wave without any success. I can confirm that there is no problem to use -O3 for vasp.lib. Does anybody have a clue on this?
Thanks.
Brane
I tried to compile VASP on an IBM Power 6 system using the modifed makefile.rs6000 or makefile.sp2. The compilation has no problem. However, the calculated total energy is wrong when I use -O3 or -O2 opimization level to compile VASP. If the optimiztion level is downgraded to the lowest one (-O0), as expected, the calculated energy is correct. A similar problem was reported ealier: http://cms.mpi.univie.ac.at/vasp-forum/ ... php?2.4616
I think I have to use the lowest optimiztion level for certain subroutines. I tried to use -O0 for radial, nonl, nonlr, paw, pseudo, and wave without any success. I can confirm that there is no problem to use -O3 for vasp.lib. Does anybody have a clue on this?
Thanks.
Brane