[lammps-users] dump_custom.cpp

Hi, I've been looking at dump_custom.cpp and found the variables
sxx,syy,szz,sxy,sxz,syz and I suspect these are the components of the
stress tensor per atom. I checked the documentation for the dump_custom
command and I can't find these arguments. Can anyone explain the exact
definition/equation used for these quantities. And, can I dump these
quantities using the dump_custom command?

Thanks

-Jan-Michael

Dear Jan,
In my opinion, these variables are outdated which were used to calcuated per atom stress sometime ago. Now, you can get the stress components using a compute command and for exact definitions, please look at compute stress/atom page. I think since a compute has been defined now to calculate stress components, these variable should be removed from dump_custom.cpp file.
I hope this helps.

Regards,
Vikas

Thanks!

Do you know the exact line to write in my input file if I want to dump the
stress per atom sxx,syy,szz on a dumpfile. I guess you have to define a
compute first and then a dump command

e.g:

compute 1 all stress/atom
dump 1 all custom 5000 SEsystem.stress tag c_1[0] c_1[1] c_1[2]
dump_modify 1 image yes scale yes flush yes

is sxx = c_1[0] or c_1[1]?

Dear Jan,
    In my opinion, these variables are outdated which were used to
calcuated
per atom stress sometime ago. Now, you can get the stress components

using

a
compute command and for exact definitions, please look at compute

stress/atom page. I think since a compute has been defined now to
calculate

stress components, these variable should be removed from dump_custom.cpp

file.

I hope this helps.

Regards,
Vikas

Hi, I've been looking at dump_custom.cpp and found the variables

sxx,syy,szz,sxy,sxz,syz and I suspect these are the components of the
stress tensor per atom. I checked the documentation for the dump_custom
command and I can't find these arguments. Can anyone explain the exact
definition/equation used for these quantities. And, can I dump these
quantities using the dump_custom command?

Thanks
-Jan-Michael
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Dear Jan,
sxx=c_1[1]. Rest looks fine…

Regards,
Vikas

There is no sxx, syy, etc in the current version of dump_custom.cpp.
They are in fact outdated. See the compute pressure command
if you want the global pressure (stress) tensor, or the compute stress/atom
command if you want the per-atom equivalent.

Steve