[lammps-users] Pouring grain from one side of box

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1

Dear All
Hi
I hope that all of you will be successful in your works. I have two questions.
1- my Images and movies from XMOVIE are very very small and I can not give a good snapshot or movie.How can i give a good image and movie? (For example for POUR example)
2- For POUR example i am going to pouring grains from top of one side of box.How can I do it? (For example I am going to pour the granular particles from top and left side of the block box. but i can not do it).
With the best regards
Hamed Maleki

Hamed Maleki
Physics department, Faculty of Science,
University of Birjand, Birjand, Iran

2

Hamed,

  1- my Images and movies from XMOVIE are very very
small and I can not give a good snapshot or
movie.How can i give a good image and movie? (For
example for POUR example)

You probably need to be using the -scale option. See
the xmovie README file:

"Note that LAMMPS output is scaled by default (so
all coordinates are from 0 to 1). Thus you need to
run xmovie like this:

xmovie -scale dump.*

to see the snapshot you expect"

  2- For POUR example i am going to pouring grains
from top of one side of box.How can I do it? (For
example I am going to pour the granular particles
from top and left side of the block box. but i can
not do it).

Specify a region at the top left side of the box using
the region command:

http://www.cs.sandia.gov/~sjplimp/lammps/doc/region.html

Then insert your granular particles using fix insert:

http://www.cs.sandia.gov/~sjplimp/lammps/doc/fix_insert.html

Paul

3

Hello everyone,

I have a question regarding a logical in temp/rescale. I pasted a part of
the subroutine where the temperature is scaled.

    if (iregion == -1) {
      for (int i = 0; i < nlocal; i++) {
  if (mask[i] & groupbit) {
      .
      .
  }
      }

    } else {
      for (int i = 0; i < nlocal; i++) {
  if (mask[i] & groupbit &&
      domain->regions[iregion]->match(x[i][0],x[i][1],x[i][2])) {
        .
        .
  }
      }
    }

What does the check for iregion == -1 mean? When the condition is not
fulfilled does the additional check
domain->regions[iregion]->match(x[i][0],x[i][1],x[i][2])) mean to check
whether the atoms belong also to the geometrical region in space originally
defined for a particular region id? Why are two different checks necessary
based on the value of iregion?

Thanks
Jaime Sanchez

4

The fix temp/rescale command has an option to apply the rescaling
only to a geometric region. This was added with the 16 May 06 patch.
So the section of code you include checks whether a
region was specified (iregion >= 0) or not (iregion = -1).

Steve