[gmx-users] extending a simulation

[Mark Abraham]

On 1/02/2011 8:27 PM, Adwait Mevada wrote:
>
> Dear gmx-users,
> In order to extend my simulations, i am using grompp in the following 
> fashion:
>
> grompp -np 8 -t amphiphilic_512dppc_50ns -c amphiphilic_512dppc_50ns 
> -e amphiphilic_512dppc_50ns -f 850ns.mdp -p dppc.top -o 
> amphiphilic_512dppc_900ns
>
> followed by mdrun
>
> mpiexec -np 8 mdrun_mpi.openmpi -np 8 -s amphiphilic_512dppc_900ns -o 
> amphiphilic_512dppc_900ns -e amphiphilic_512dppc_900ns -g 
> amphiphilic_512dppc_900ns &
>
> I am using gromacs 3.3.3 and the reason for using grompp for extension 
> is because i wanted to change nxtxout, nxtvout, values from the 
> previous file.
>
> my question is when using grompp in the above fashion i get this message:
>
> Checking consistency between energy and charge groups...
> getting data from old trajectory ...
> Reading Coordinates, Velocities and Box size from old trajectory
> Will read whole trajectory
> trn version: GMX_trn_file (single precision)
> Reading frame    1700 time 51000.000
> Using frame at t = 51000 ps
> Starting time for run is 51000 ps
> Opened ampiphilic_512dppc_50ns.edr as single precision energy file
> Reading frame   1700 time 51000.000
>
> READ 3 PRESSURE COUPLING MU'S FROM ampiphilic_512dppc_50ns.edr
>
> writing run input file...
>
> here does single precision imply that grompp is not using double 
> precesion

Yes.

> data even though the input file .trr is full precision file

Full precision could be single or double.

> if so is it possible to use full precision for extension of trajectory.

You are doing so.

Mark