Dear all,
I am running a polymer simulation with bond, angle, dihedral and nonbonded potentials. The sample was deformed under nvt ensemble.
the specific commands are as folows:
#read_data 1000_PE_LAMMPS_INPUT
read_restart pmr.restart.5000000
pair_modify tail yes
neighbor 1.0 bin
timestep 1.0
run_style verlet
fix 1 all deform 1 x vel 0.0003 units box
fix 2 all nvt temp 100 100 500
When the simulation was run directly from the data file and then by using a intermediate restart file, the output at a given step say 5183000 were compared and were found to be varying.
First few lines from the dump file of both runs are shown below,
For run from original datafile,
ITEM: ATOMS id x y z
1 -416.997 9.7084 11.587
2 -418.323 8.93339 11.6771
3 -419.256 9.61928 12.6947
4 -420.546 8.83569 12.88
5 -420.327 7.45046 13.5581
6 -421.494 6.50961 13.3391
7 -421.181 5.04872 13.6829
8 -421.296 4.74522 15.1938
9 -421.424 3.26868 15.6285
10 -421.471 3.11456 17.1354
For run from restart file at 5000000
ITEM: ATOMS id x y z
1 -417.077 9.70336 18.4055
2 -417.566 9.08762 17.1175
3 -418.873 9.73894 16.5819
4 -419.58 9.15077 15.3765
5 -419.859 7.66144 15.5719
6 -420.442 6.9203 14.349
7 -420.553 5.42464 14.6078
8 -421.461 5.14037 15.7876
9 -421.411 3.69951 16.2402
10 -422.2 3.43722 17.526
The variation in the y and z coordinates seem significant. The correlation between them along each axis is given below,
X_original and X_ restart --> 0.997742
Y_original and Y_restart --> 0.940218
Z_original and Z_restart --> 0.935896
Why do these variations occur, and are variations in the acceptable range?
Thanks
Vivek Ananth
IMSc,Chennai