Re: [ESPResSo-users] Control Temperature in version 3.2

[Axel Arnold]

Hi!

If that works, the problem is probably rather that you make some assumption on the degrees of freedom in your script, which are no longer true. In previous versions of Espresso, if ROTATION was compiled in, the DOF per particle were 6. Now, if ROTATION_PER_PARTICLE is on, it is still 3 for all particles that are still rotationally invariant, so in your case, all. Best is, that you get rid of this assumption in the script.

Best regards,
Axel

On 05/13/2013 09:50 PM, Salvador H-V wrote:

Hi Olaf, 

Thanks for your quickly reply.

You were right, turning off the rotation (I also turned off virtual sites) solve the "problem".

Now the compilation of ESPresSo is as follows:

ESPResSo-3.2.0

{ Compilation status { FFTW } { CONSTRAINTS } { BOND_ANGLE_HARMONIC } { GAUSSIAN } { HERTZIAN } { PARTIAL_PERIODIC } { LENNARD_JONES } { MODES } { EXTERNAL_FORCES } { TABULATED } { SOFT_SPHERE } { LENNARD_JONES_GENERIC } { MASS } { ELECTROSTATICS } { BOND_CONSTRAINT } { EXCLUSIONS } }

 

The control of temperature is ok for the three potentials (WCA, Hertzian and Gaussian).

Thanks a lot, 

Salvador

On Mon, May 13, 2013 at 1:48 PM, Olaf Lenz <address@hidden> wrote:

Hi!

Could you try whether this also happens when you turn off
ROTATION_PER_PARTICLE?

In general, when you just do a standard simulation, DO NOT turn on
ROTATION, as this will make ESPResSo significantly slower.

Anyway, this is a problem that should be solved.

Olaf

On 05/13/2013 08:43 PM, Salvador H-V wrote:
> Dear All,
>
> I have a one-dimensional system of spherical particles of diameter
> sigma move along a line.
>
> I am using #   --- The simulation Box is periodic in only one
> direction setmd periodic 1 0 0 setmd box_l $bl $bl $bl and the
> interaction potential is either the WCA, hertzian or Gaussian
> potential
>
> My compilation of ESPresSo is as follows: ESPResSo-3.2.0 {
> Compilation status { FFTW } { CONSTRAINTS } { ROTATIONAL_INERTIA } {
> BOND_ANGLE_HARMONIC } { GAY_BERNE } { GAUSSIAN } { COMFIXED } {
> HERTZIAN } { PARTIAL_PERIODIC } { LENNARD_JONES } {
> VIRTUAL_SITES_RELATIVE } { EXTERNAL_FORCES } { TABULATED } { ROTATION
> } { SOFT_SPHERE } { VIRTUAL_SITES_NO_VELOCITY } {
> LENNARD_JONES_GENERIC } { ROTATION_PER_PARTICLE } { BOND_VIRTUAL } }
>
> I am running the simulation with: { langevin 1.0 1.0 }
>
> However, with the current version of ESPresSo 3.2.0, I have problems
> to control the temperature with any of the above mentioned
> potentials.
>
> WCA-Potencial {0 0 lennard-jones 1.0 0.5 0.5612310241546865 0.25 0.0
> 0.0 0.0 } t=1.000000000000001 E=1.784989386884216, T=3.5299316707096
> (LJ cap = 20) t=2.000000000000001 E=2.105429430274374,
> T=4.149024028202554 (LJ cap = 30)
>
> However, for the same script with the same set of parameters using
> version 3.1.1, I get the following {0 0 lennard-jones 1.0 0.5
> 0.5612310241546865 0.25 0.0 0.0 0.0 } { langevin 1.0 1.0 }
>
> t=1.000000000000001 E=0.4317609210550725, T=0.8207101850023056 (LJ
> cap = 20) t=2.000000000000001 E=0.5662738721667048,
> T=1.071506110193384 (LJ cap = 30)
>
> I observe the same problem with both WCA and Hertzian potentials.
> Correct temperature in 3.1.1 but not in 3.2.0
>
> Does any body could shed some light?  Any suggestion would be
> greatly appreciated.
>
> Thanks a lot in advance,
>
> Salvador
>
>
>

--
Dr. rer. nat. Olaf Lenz
Institut für Computerphysik, Allmandring 3, D-70569 Stuttgart
Phone: +49-711-685-63607

--
=o=o=o=o=o=o=o=o=o=o=o=o=o=o=o=o=o=o=o

Dr. Salvador Herrera-Velarde
Simulacion Computacional de Materia Condensada Blanda
Sub-Direccion de Investigacion y Posgrado
Instituto Tecnologico Superior de Xalapa (ITSX)
Instituto Tecnológico Superior de Xalapa
Sección 5A Reserva Territorial s/n, 

Col. Santa Bárbara, 

CP 91096
Xalapa, Ver. Mexico


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Este correo ha sido editado para evitar el uso de acentos y guardar compatibilidad entre
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-- 
JP Dr. Axel Arnold
ICP, Universität Stuttgart
Pfaffenwaldring 27
70569 Stuttgart, Germany
Email: address@hidden
Tel: +49 711 685 67609