Compatibility between single precision and double precision

User discussions
1

GROMACS version:
GROMACS modification: No

@jalemkul @hess
I have installed GROMACS (version 2024.1) on different machines, both with and without the -DGMX_DOUBLE=on flag.

My question is: If I start an MD simulation on one machine, can I continue or extend the simulation on another machine, regardless of whether it was installed with or without this flag.

I am asking because when I attempted this, I encountered the following error: Warning: no access to tty (Inappropriate ioctl for device). Thus no job control in this shell.

I both gromacs the only difference is -DGMX_DOUBLE=on during installation.

Thanks

2

Why would you want to install GROMACS with different precision on different machines?

All files are compatible between single and double precision. I think that the only thing you can not do is continue simulations with appending.

3

Thanks @hess for addressing my query.

I had GROMACS installed on one machine (machine-1, a supercomputer) with double precision. However, it was very costly and lacked free cores, so I installed the same version of GROMACS without specifying the -DGMX_DOUBLE=on flag on another machine (machine-2, a normal server).

I used the command "gmx mdrun -v -noappend -deffnm pro_1 -pin on -dlb yes -ntmpi 10 -ntomp 6 -nb gpu" for the first run on machine-2. Due to maintenance, I can’t use this machine for some time so, I thought of extending this run on machine-1. Upon submitting the job, it terminates with the error: "Warning: no access to tty (Inappropriate ioctl for device). Thus no job control in this shell." and " /var/spool/pbs/mom_priv/jobs/[3671012.fe3-adm.SC](http://3671012.fe3-adm.SC): Command not found."

4

The error message is related to access to the terminal and has nothing to do with GROMACS.