[gmx-users] Gromacs precision and the precision of values set in the mdp file

Mark Abraham mark.j.abraham at gmail.com
Wed Jan 14 09:16:24 CET 2015

On Wed, Jan 14, 2015 at 12:39 AM, Eric Smoll <ericsmoll at gmail.com> wrote:

> Hello Gromacs users,
> What is the precision limit for values entered in an mdp file for a single
> precision gromacs simulation?

For "mixed precision" probably float.

> Does this increase when using gromacs is
> compiled in double precision?


There's too many moving parts for a general and definitive answer. To be
really sure, you'd want to construct a test case of a single MD step with a
few atoms that produces the same output in both precisions, so that when
you change the .mdp input to a value that requires double precision for the
full representation you can see whether the outputs change.


> Best,
> Eric
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