[gmx-users] Specifying the number of OpenMP threads that g_hbond uses

[Andrew DeYoung]

Hi, 

>From the web page

http://www.gromacs.org/About_Gromacs/Release_Notes/Versions_4.6.x ,

it looks like parallelization for g_hbond (via OpenMP) was added in version
4.6.x.

What is a typical command to run g_hbond in parallel?  Since I mostly have
experience with Gromacs 4.5.5 (which for mdrun has auto MPI threading as the
default parallelization, which means I only have to specify the number of
threads with -nt), I am not sure how to launch OpenMP for g_hbond in 4.6.x.


When I just run g_hbond in 4.6.1 with no extra flags, the output says,
"Frame loop parallelized with OpenMP using 8 threads."  Is there any way to
change the number of OpenMP threads that g_hbond uses?

Thanks so much!

Andrew DeYoung
Carnegie Mellon University