the difference between Windows and Linux of Lammps

Hi all,

Could you tell me the difference between Windows and Linux of Lammps, if the results of same in file is different, which one is more correct?

Regards,

Yongning

Hi all,

Could you tell me the difference between Windows and Linux of Lammps, if the
results of same in file is different, which one is more correct?

the one that gives the (more) correct answer.

the OS itself doesn't (shouldn't) make a difference.

_but_, different *versions* of LAMMPS do make a difference, if one has
a bug that the other doesn't,
and MD trajectories diverge slowly(!), because MD is solving a system
of coupled linear partial differential equations, which is essentially
a system that can exhibit chaotic behavior (ever heard of the
"butterfly effect"?). this effect is often enhanced by using a
different number of processors, a different compiler, difference
compiler optimization levels etc.

now, which of those conditions exactly applies to your question, is
impossible to say from here. only you can check it out.

axel.

Thanks for your help

There are several important reasons to use the linux (or mac) versions
of LAMMPS over the pre-built windows:

1) Shell environment:
Because LAMMPS does not come with as much analysis tools as other MD
programs, there is a high probability that you will have to write some
small scripts yourself (to analyze the results of your simulation, for
example). A shell/unix-like environment makes doing this much easier.
Unless you install something like mingw or cygwin, or WUBI in windows,
you will not have access to a shell environment (including bash, g++,
python, awk, perl, sed).

Writing your own code may not be necessary. Several free tools have
been written such as pizza.py and moltemplate (to build the simulation
input/data files for LAMMPS, and process the results). But without a
shell environment, (python and bash), these tools won't work either.
(exception: VMD/topotools work.)

2) If you use a pre-built binary, you will not be able to examine the
source-code to find out why LAMMPS is not behaving the way you expect.
LAMMPS often halts or crashes (there are bugs in any large program).
When it does this, it usually prints out the line in the source code
(pair.cpp:728). Examining that file help you figure out what you are
doing wrong, or help you find out if there is a bug in the program (or
in the documentation).

3) The windows binaries tend to be 6 months older, and have more bugs
or less features.

4) For this reason, nobody on the mailing list is going to be very
friendly if you run into problems using LAMMPS and need help.

So windows may be a fine environment for running LAMMPS simulations,
but windows is not the place to do all the hard work you need to do to
get it to work: preparing the input files for LAMMPS, debugging input
file problems, and interpreting the LAMMPS results. (unless you have
something like mingw or cygwin, or WUBI)

(feel free to correct me if I'm wrong and things have changed recently)
Cheers!

Andrew

There are several important reasons to use the linux (or mac) versions
of LAMMPS over the pre-built windows:

1) Shell environment:
Because LAMMPS does not come with as much analysis tools as other MD
programs, there is a high probability that you will have to write some
small scripts yourself (to analyze the results of your simulation, for
example). A shell/unix-like environment makes doing this much easier.
Unless you install something like mingw or cygwin, or WUBI in windows,
you will not have access to a shell environment (including bash, g++,
python, awk, perl, sed).

while i am not at all comfortable using windows myself, one has to
acknowledge the fact, that a lot of people are. and those tend to be
equally uncomfortable using a linux/unix machine and the corresponding
unix-oid tools.

Writing your own code may not be necessary. Several free tools have
been written such as pizza.py and moltemplate (to build the simulation
input/data files for LAMMPS, and process the results). But without a
shell environment, (python and bash), these tools won't work either.
(exception: VMD/topotools work.)

python is supposedly quite usable (and popular) on windows.

2) If you use a pre-built binary, you will not be able to examine the
source-code to find out why LAMMPS is not behaving the way you expect.
LAMMPS often halts or crashes (there are bugs in any large program).
When it does this, it usually prints out the line in the source code
(pair.cpp:728). Examining that file help you figure out what you are
doing wrong, or help you find out if there is a bug in the program (or
in the documentation).

i wish more people would do that, but judging from the average content
of inquiries here, this is wishful thinking. :wink:

3) The windows binaries tend to be 6 months older, and have more bugs
or less features.

not all of them. :wink:

4) For this reason, nobody on the mailing list is going to be very
friendly if you run into problems using LAMMPS and need help.

So windows may be a fine environment for running LAMMPS simulations,
but windows is not the place to do all the hard work you need to do to
get it to work: preparing the input files for LAMMPS, debugging input
file problems, and interpreting the LAMMPS results. (unless you have
something like mingw or cygwin, or WUBI)

(feel free to correct me if I'm wrong and things have changed recently)

yes, they did. check out recent posts to this very mailing list and
http://git.icms.temple.edu/rpm/windows.html

axel.