[gmx-users] More accurate potential energy in output?

David van der Spoel spoel at xray.bmc.uu.se
Thu Jul 12 14:28:16 CEST 2012

On 2012-07-12 14:01, Markus Kaukonen wrote:
> Dear Gromacs,
> Is there really no other way to get the potential energy of the system
> more accurately (6 digits)
> than compiling in double precision?
> Gromacs is giving eight digits after an succesfull cg minimization
> even when compiled with single precision.
> Eight digits would be enough for me.
> Terveisin, Markus

g_energy -dp IIRC.
g_energy -h is your friend. By the way in single precision you have 7-8 
digits only.
> On 7/11/12 3:14 PM, Markus Kaukonen wrote:
>> Dear Gromacs,
>> I'm trying to build a QM/MM with gromacs as MM.
>> The thing would be run by ASE-simulation environment
>> (https://wiki.fysik.dtu.dk/ase/).
>> Question: I'm trying to get the potential energy of a single atomic
>> configutation.
>> Is it possible to get the potential energy of a given configuration
>> with more than 5 digits?
> Compile and run in double precision.
> -Justin

David van der Spoel, Ph.D., Professor of Biology
Dept. of Cell & Molec. Biol., Uppsala University.
Box 596, 75124 Uppsala, Sweden. Phone:	+46184714205.
spoel at xray.bmc.uu.se    http://folding.bmc.uu.se

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