Dear Lammps Users, Developers,

I am using lammps to do some molecular statics. I displace the atoms and then I minimize the structure. I repeat such an operation for a large number of step.

At the end of the number of increment (I have XX time displace + minimize in the input file), the code just does not stop.

Also, because I only want the snapshot at the end of every minimization, I dump every 1000000 steps, which means never.

Do you have any idea of why?

Thanks,

Sebastien

Sebastien,

Your question seems unclear. Perhaps you could post an example input script.

When you say "the code just does not stop", I assume you mean that the minimization doesn't converge within the time you waited. You could try changing the minimization parameters to make it end sooner.

You can also change the dump frequency so that you get more snapshots.

Paul

Paul,

Actually, the minimization converged within the wall time. Lammps just does not stop after the last minimization and I have no idea of why. The last time it wrote something was at 7pm and it is not almost 11pm. lammps is still running and I have no idea of what is it doing.

here are the stat of the last minimization to show you the convergence.

Minimization stats:

Stopping criterion = energy tolerance

Energy initial, next-to-last, final =

-40388.9413657 -40388.984296 -40388.984296

Force two-norm initial, final = 0.184992 0.000106844

Force max component initial, final = 0.0129694 2.36187e-05

Final line search alpha, max atom move = 2.46447e-08 5.82077e-13

Iterations, force evaluations = 2363 17964

Pair time (\) = 236\.03 \(81\.2528\)
Neigh time \() = 0 (0)

Comm time (\) = 37\.0695 \(12\.7611\)
Outpt time \() = 1.16373 (0.400612)

Other time (%) = 16.2251 (5.58546)

And here, it the example of script I am using:

# Minimize after deformation to calculate a Peierls Stress

# we start with an unrelaxed configuration: first step, minimize with 0 displacement

units metal

boundary p s p

atom_style atomic

read_data data.meam

pair_style eam/fs

pair_coeff * * Mg_mm.eam.fs Mg

neighbor 2.0 bin

neigh_modify delay 0

#definition of the upper block

region upper block INF INF 323.491210937500000 INF INF INF units box

region lowerL block INF 6.4178000000000000009 INF 10.0000000000000000009 INF INF units box

region lowerM block 6.4178000000000000009 327.357793612670898 INF 10.0000000000000000009 INF INF units box

region lowerR block 327.357793612670898 INF INF 10.0000000000000000009 INF INF units box

region forstress1 block 6.4178000000000000009 327.357793612670898 INF 323.491210937500000 INF INF units box

group upper region upper

group lowerL region lowerL

group lowerM region lowerM

group lowerR region lowerR

group forstress1 region forstress1

displace_atoms lowerL move 0.0 0. 0. units box

displace_atoms lowerM move 0.0 0. 0. units box

displace_atoms lowerR move 0.0 0. 0. units box

fix 1 lowerL setforce NULL 0.0 NULL

fix 2 lowerR setforce NULL 0.0 NULL

fix 3 lowerM setforce NULL 0.0 NULL

fix 4 upper setforce NULL 0.0 NULL

thermo 1

thermo_style custom step f_3[1]

compute 2 all centro/atom

dump 3 all custom 50000000 dump.movie tag x y z c_2

dump 9 forstress1 custom 10000000 dump.syz.* fx

min_modify dmax 0.005

minimize 0.0 1.0e-14 100000 100000

unfix 1

unfix 2

unfix 3

unfix 4

fix 1 lowerL setforce 0.0 0.0 0.0

fix 2 lowerR setforce 0.0 0.0 0.0

fix 3 lowerM setforce 0.0 0.0 0.0

fix 4 upper setforce 0.0 0.0 0.0

displace_atoms lowerL move .03337775936126708979 0. 0. units box

displace_atoms lowerM move .03337775936126708979 0. 0. units box

displace_atoms lowerR move .03337775936126708979 0. 0. units box

min_modify dmax 0.005

minimize 0.0 1.0e-14 100000 100000

displace_atoms lowerL move .03337775936126708979 0. 0. units box

displace_atoms lowerM move .03337775936126708979 0. 0. units box

displace_atoms lowerR move .03337775936126708979 0. 0. units box

min_modify dmax 0.005

minimize 0.0 1.0e-14 100000 100000

displace_atoms lowerL move .03337775936126708979 0. 0. units box

displace_atoms lowerM move .03337775936126708979 0. 0. units box

displace_atoms lowerR move .03337775936126708979 0. 0. units box

min_modify dmax 0.005

minimize 0.0 1.0e-14 100000 100000

displace_atoms lowerL move .03337775936126708979 0. 0. units box

displace_atoms lowerM move .03337775936126708979 0. 0. units box

displace_atoms lowerR move .03337775936126708979 0. 0. units box

min_modify dmax 0.005

minimize 0.0 1.0e-14 100000 100000

displace_atoms lowerL move .03337775936126708979 0. 0. units box

displace_atoms lowerM move .03337775936126708979 0. 0. units box

displace_atoms lowerR move .03337775936126708979 0. 0. units box

min_modify dmax 0.005

minimize 0.0 1.0e-14 100000 100000

... (I repeated the last 5 lines 50 times).

I have the results of the last minimization adn everything is great but code still running.

Sebastien

Sebastien,

Are you using the current updated version of LAMMPS? If not, I'd strongly recommend that you update and try it again.

I had to slightly modify your input script to get it to parse properly, but it ran to completion here on my machine. The line I changed was as follows:

pair_coeff * * Mg_mm.eam.fs Mg Mg

I also assumed that you are using the Mg_mm.eam.fs and data.meam files as-is from the LAMMPS distribution. If not, please send the files that you're using.

As-is, the output from the run looked funny: zero everywhere for the f_3[1] quantity.

Here's the final output I'm seeing (pasted below). The run completed very quickly.

Paul

Setting up minimization ...

Memory usage per processor = 2.64327 Mbytes

Step 3[1]

2162 0

2163 0

Loop time of 0.016 on 1 procs for 1 steps with 128 atoms

Minimization stats:

Stopping criterion = failed linesearch

Energy initial, next-to-last, final =

-47.375139111 -47.375139111 -47.375139111

Force two-norm initial, final = 0 0

Force max component initial, final = 0 0

Final line search alpha, max atom move = 0 0

Iterations, force evaluations = 1 0

Pair time (\) = 0 \(0\)
Neigh time \() = 0 (0)

Comm time (\) = 0 \(0\)
Outpt time \() = 0 (0)

Other time (%) = 0.016 (100)

Nlocal: 128 ave 128 max 128 min

Histogram: 1 0 0 0 0 0 0 0 0 0

Nghost: 718 ave 718 max 718 min

Histogram: 1 0 0 0 0 0 0 0 0 0

Neighs: 12141 ave 12141 max 12141 min

Histogram: 1 0 0 0 0 0 0 0 0 0

FullNghs: 24282 ave 24282 max 24282 min

Histogram: 1 0 0 0 0 0 0 0 0 0

Total # of neighbors = 24282

Ave neighs/atom = 189.703

Neighbor list builds = 0

Dangerous builds = 0