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 - 09:30:03 PST
