Comparing serial to parallel version
Posted: Tue Apr 28, 2009 10:48 pm
I am interested in learning how I might confirm that my parallel version of VASP is working properly. Specifically, I'm concerned because I get a different final energy when I run the same input on a different number of processors. See the following:
NProc F E0 d E
1
-.74924471E+03 -.74855157E+03 -.165608E+01
2
-.74924477E+03 -.74855118E+03 -.165607E+01
4
-.74924458E+03 -.74855221E+03 -.165622E+01
16
-.74924626E+03 -.74855516E+03 -.166517E+01
32
-.74924372E+03 -.74855286E+03 -.164182E+01
The more processors, the further from the single-processor energy. There must be a standard input that I can use to test my installation (to compare my output to a standard output). I have searched the VASP forum, but have been unable to find this information if it is out there.
NProc F E0 d E
1
-.74924471E+03 -.74855157E+03 -.165608E+01
2
-.74924477E+03 -.74855118E+03 -.165607E+01
4
-.74924458E+03 -.74855221E+03 -.165622E+01
16
-.74924626E+03 -.74855516E+03 -.166517E+01
32
-.74924372E+03 -.74855286E+03 -.164182E+01
The more processors, the further from the single-processor energy. There must be a standard input that I can use to test my installation (to compare my output to a standard output). I have searched the VASP forum, but have been unable to find this information if it is out there.