WARNING: Inconsistent image flags

HI,

I am dumping unwrap coordinates ( xu yu zu ) in dump files.

using rerun command to find energies between two groups.

rerun …/1/dump.lammps every 1 dump x y z

its giving following warning.

"WARNING: Inconsistent image flags"

Is this fine, what should i do to overcome this warning?

Thanks

spandana

HI,

I am dumping unwrap coordinates ( xu yu zu ) in dump files.

using rerun command to find energies between two groups.

rerun ../1/dump.lammps every 1 dump x y z

its giving following warning.

"WARNING: Inconsistent image flags"

Is this fine, what should i do to overcome this warning?

this will cause your desktop to self-destruct in about 30 mins. you
better make a backup right away.

axel.

Thanks for the concern.
Sorry sir to revert back again, but I still cant find the mistake.

Can you please point out the mistake.

Thanks a lot

spandana

Thanks for the concern.
Sorry sir to revert back again, but I still cant find the mistake.

Can you please point out the mistake.

The mistake is that you didn't calibrate the input file defibrillator.

Thanks a lot

you are most welcome.

axel.

Thanks sir,

here is my input file,

units real
dimension 3
atom_style full

read_data data.lammps
include parm.lammps

neighbor 2 bin
neigh_modify check yes

group grp1 molecule <> 1 20
group grp2 molecule <> 21 40

compute diff_pe grp1 group/group grp2 kspace yes

thermo_style custom step pe ecoul elong evdwl c_diff_pe
thermo 100
thermo_modify flush yes

rerun …/1/dump.lammps dump x y z

Please, Need in help, its giving warning, inconsistent image flags

Thanks

spandana

from error section, I got the following information

*Inconsistent image flags*
The image flags for a pair on bonded atoms appear to be inconsistent. Inconsistent means that when the coordinates of the two atoms are unwrapped using the image flags, the two atoms are far apart. Specifically they are further apart than half a periodic box length. Or they are more than a box length apart in a non-periodic dimension. This is usually due to the initial data file not having correct image flags for the 2 atoms in a bond that straddles a periodic boundary. They should be different by 1 in that case. This is a warning because inconsistent image flags will not cause problems for dynamics or most LAMMPS simulations. However they can cause problems when such atoms are used with the fix rigid or replicate commands.
Is there anything going bad due to PBC, then how to overcome it
Thanks
spandana

from error section, I got the following information

Inconsistent image flags The image flags for a pair on bonded atoms appear
to be inconsistent. Inconsistent means that when the coordinates of the two
atoms are unwrapped using the image flags, the two atoms are far apart.
Specifically they are further apart than half a periodic box length. Or they
are more than a box length apart in a non-periodic dimension. This is
usually due to the initial data file not having correct image flags for the
2 atoms in a bond that straddles a periodic boundary. They should be
different by 1 in that case. This is a warning because inconsistent image
flags will not cause problems for dynamics or most LAMMPS simulations.
However they can cause problems when such atoms are used with the fix rigid
or replicate commands.

Is there anything going bad due to PBC, then how to overcome it

bad questions don't get better by repeating them.

it is your data and your simulation. you know what it should be, so
you have to verify that LAMMPS is doing what you want. as i mentioned
before, it doesn't suddenly become correct or wrong because of
somebody's say-so. specifically, if that person cannot know what it is
that your want. errors (or warnings) are not resolved by silencing
them, but by understanding why they happen and then making a conscious
decision. no person worth listening to, will do this for you.

axel.

Thanks sir,

I ran two simulations, with compute group/group, with “run” and “rerun”

Now, with ‘run’ ( gives no warning inconsistent image flags ) energy values are same as rerun ( with warning inconsistent flags).

I can assure myself that warning inconsistent flags are not effecting my energies.

Is this correct?

Thanks

spandana

Thanks sir,

I ran two simulations, with compute group/group, with "run" and "rerun"

Now, with 'run' ( gives no warning inconsistent image flags ) energy
values are same as rerun ( with warning inconsistent flags).

I can assure myself that warning inconsistent flags are not effecting my
energies.

Is this correct?

unfortunately, i have run out of affirmative bytes on my computer.
i'll run a program to regenerate them over the weekend and will be
able to answer next week.

axel.

Axel is apparently in a playful mood this AM …

As the manual says,it likely won’t cause you problems, but I don’t think

writing a dump file and reading it back in should typically

generate that message. Can you post a simple input script
that generates the dump file that the rerun script gives the
warning on?

Steve

Hi,

I am attaching the directory,

system: 100 united nonane, first run normally ( input file in.nonane)

when I use the dump file for rerun command, I can see the warning.

Thanks

spandana

rerun.tar (750 KB)

The issue was that you were reading unwrapped coords from the

dump file and they were being remapped to the periodic box
which incremented the image flags. I modified version
of read_dump in the 18Sep patch should handle that case

now.

Steve