ntt=1 doesn't use the random number generator, so won't be affected by the
seed (ntt=3 is). if you set temp0>0, then the seed should affect the
initial velocity assignment.
On Fri, Feb 4, 2022 at 12:01 PM Dr. Anselm Horn <anselm.horn.fau.de> wrote:
> Dear Carlos,
>
> I did not read in any velocities, since I used a structure from a
> minimization. The thermostat was NTT=1.
>
> Do I miss something?
>
> Best regards,
>
> Anselm
>
>
> Am 04.02.2022 um 16:00 schrieb Carlos Simmerling:
> > which thermostat did you use? also, did you read velocities from the
> input
> > coordinates? these are two places that can be affected by the seed.
> >
> > On Fri, Feb 4, 2022 at 9:09 AM Dr. Anselm Horn <anselm.horn.fau.de>
> wrote:
> >
> >> Dear Amber experts,
> >>
> >> I have a short question regarding the random number generator for
> >> initial velocities (TEMPi) on GPUs:
> >>
> >> I ran two MD simulations in a periodic solvent box starting from a
> >> minimized structure, with weak-temperature coupling (NTT=1) and an
> >> initial temperature of 50 K (TEMPi=50.0); for each simulation, I used
> >> an explicit, but different random number seed (ig=NNN). I used the
> >> executable pmemd.cuda_DPFP (Amber20, patch12) on a A40-GPU, since my
> >> original intention was to test whether system relaxation might be save
> >> on GPUs.
> >>
> >> The resulting trajectories of the two runs, however, were identical,
> >> although different random seeds were used.
> >>
> >> Is the ig-seed not used on GPUs, or for NTT=1 in general?
> >>
> >> Maybe I misunderstood the section 21.6.7 in the Amber manual about
> >> temperature regulation...
> >> I did not check ig=-1 up to now, though.
> >>
> >> Best regards,
> >>
> >> Anselm
> >>
> >> Bioinformatik | NHR.FAU
> >> Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
> >> Germany
> >>
> >>
> >>
> >>
> >>
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Received on Fri Feb 04 2022 - 09:30:04 PST
