I am using the free version of charmm (v43) which I complied with:
./install.com gnu xlarge x86_64
./install.com gnu M
I am using GBSW solvation model and I was doing some testing to see how fast was the procedure. Also, my system is constrained with EMAP.
I got really strange results, so I assume CHARMM has not complied properly.
When I run it on 4, 8, 12 and 16 cores the CPU time shows it takes more to run the script on 16 cores than on 4:
NP 4 8 12 16
CPU time/min 25.53 27.27 29.09 29.87
I also tried with ./install.com gnu M MPICH ADM64 and some other like ./install.com gnu xlarge ifort x86_64, and than recompile it with mpi option, but it does not work.
I tried to recompile it with em47t, but I could not do it successfully as it was possible to compile it only in the serial version.
Can anyone help me with this issue? I suppose I am just not doing it properly, so I would appreciate the help.