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Re: [lammps-users] FW: Restart not exact
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Re: [lammps-users] FW: Restart not exact


From: "Sengupta, S." <S.Sengupta@...2493...>
Date: Sun, 8 Oct 2017 09:42:54 +0000

Thanks for the help. Yes, the grids are changing which causes the slight difference in the e_long.

Soumyadipta
________________________________________
From: Axel Kohlmeyer [akohlmey@...24...]
Sent: 06 October 2017 20:25
To: Sengupta, S.
Cc: lammps-users@lists.sourceforge.net
Subject: Re: [lammps-users] FW: Restart not exact

On Fri, Oct 6, 2017 at 2:03 PM, Sengupta, S. <S.Sengupta@...2493...<mailto:S.Sengupta@...2493...>> wrote:
Dear users,

I ran a simulation using lambda_test.txt . I am trying to restart the simulation from 2950000 time steps using lambda_rst.txt. I am using the lammps 17Nov/16 version.

The thermo diagnostics for restart are not exactly matching the 2950000 time step data in the log file. I have kept the number of processors same and used the default newton setting in both the restart and original simulation.

Restart thermo

Step Temp E_pair E_mol TotEng Press Volume Density
2950000    300.44816   -37677.886    44295.361    20505.773    544.40548     224319.2    1.7848003

Original run thermo
Step Temp E_pair E_mol TotEng Press Volume Density
2950000    300.44816   -37679.196    44295.361    20504.462    548.64091     224319.2    1.7848003


As you can see, the diagnostics are not exactly the same. Is this acceptable ?

it ​depends. from the ​information you provide, it is not possible to decode, which part of the potential energy is actually different.
please have a closer look at the output for PPPM. are the FFT grids different?
for PPPM, the FFT grid is determined only at the beginning of a run. if your system volume changes during the run, the grid may change and thus cause a different in E_long.

axel.



Please let me know if other files are needed.

Thanks
Soumyadipta


________________________________________
From: Sengupta, S.
Sent: 06 October 2017 17:51
To: lammps-users@lists.sourceforge.net<mailto:lammps-users@lists.sourceforge.net>
Subject: Restart not exact

I ran a simulation using lambda_test.txt . I am trying to restart the simulation from 2950000 time steps using lambda_rst.txt. I am using the lammps 17Nov/16 version.

The thermo diagnostics for restart are not exactly matching the 2950000 time step data in the log file. I have kept the number of processors same and used the default newton setting in both the restart and original simulation.

Restart thermo

Step Temp E_pair E_mol TotEng Press Volume Density
2950000    300.44816   -37677.886    44295.361    20505.773    544.40548     224319.2    1.7848003

Original run thermo
Step Temp E_pair E_mol TotEng Press Volume Density
2950000    300.44816   -37679.196    44295.361    20504.462    548.64091     224319.2    1.7848003


As you can see, the diagnostics are not exactly the same. Is this acceptable ?

I have attached the log file from the original simulation (log.lammps) and the restart file at 2950000 steps for your reference.

Thanks
Soumyadipta


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--
Dr. Axel Kohlmeyer  akohlmey@...24...<mailto:akohlmey@...24...>  http://goo.gl/1wk0
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.