Hi, everyone,
I’ve tried to reproduce examples from lammps in examples folder after finished compiling lammps on my own desktop. But it seems i can’t get the exactly same value in the log file after around 1000 time steps. I used the same number of cores as the example did, but still didn’t get it right. Could anybody help me to find out what could possibly going wrong?
On lammps manual, it mentioned lammps do not produce the same answer on different machines or number of processors, but statistical properties (average temperature or energy) should be still be the same. I am also confused if this average value mean average over the whole simulation or the number given in a log file.
Here are two log files for Colloid example, one from lammps example and the other I got from my own machine:
1.
Step Temp E_pair TotEng Press Volume
0 1.44 -2.2136534e-06 1.4383978 0.014383923 90000
1000 1.9558819 -0.00044998322 1.9532587 0.01784589 99146.35
2000 2.0558568 0.011295331 2.0648679 0.021858185 96654.425
3000 2.1809647 0.0091754217 2.1877168 0.031294876 68756.47
4000 2.1960934 0.0028186107 2.1964719 0.049318667 42974.984
5000 2.1463273 0.012748525 2.156691 0.073994939 28660.577
6000 2.1073992 0.0076702482 2.1127279 0.097655994 21544.211
7000 2.0845788 -0.0022301947 2.0800324 0.1101457 17791.284
8000 2.0651397 0.0033390713 2.0661842 0.12822835 15494.655
9000 2.0578744 0.0021876274 2.0577755 0.14877329 13860.573
…
39000 2.0047353 0.070614231 2.073122 0.80274462 4289.5501
40000 2.0379085 0.038227025 2.0738712 0.71338936 4246.7929
41000 1.9952571 0.088622162 2.0816623 0.81307645 4200.0671
42000 2.0042363 0.073467747 2.0754771 0.79982857 4148.4054
43000 2.0189089 0.066082632 2.0827483 0.7951291 4081.3285
44000 2.0380445 0.051364672 2.0871447 0.77601424 4031.596
45000 2.0176888 0.071201051 2.086648 0.8814278 3973.177
46000 2.0315294 0.062175754 2.0914479 0.80448793 3920.2923
47000 1.999217 0.091219176 2.0882149 0.97776147 3870.1695
48000 2.0031904 0.091014449 2.0919791 0.9661011 3813.1611
49000 1.9880642 0.10889214 2.0947474 1.0234859 3760.5992
50000 2.0236194 0.078957514 2.1003284 0.99741945 3720.1333
Loop time of 8.99595 on 1 procs for 50000 steps with 900 atoms
Step Temp E_pair TotEng Press Volume
0 1.44 -2.2136534e-06 1.4383978 0.014383923 90000
1000 1.9558819 -0.00044998322 1.9532587 0.01784589 99146.35
2000 2.0558568 0.011295331 2.0648679 0.021858185 96654.425
3000 2.1809647 0.0091754217 2.1877168 0.031294876 68756.47
4000 2.1960934 0.0028186107 2.1964719 0.049318667 42974.984
5000 2.1463273 0.01274853 2.156691 0.07399494 28660.577
6000 2.1073957 0.0076738214 2.1127279 0.097657166 21544.21
7000 2.0843838 -0.0020113033 2.0800565 0.11036041 17791.244
8000 2.0609642 0.005621656 2.0642959 0.13521499 15495.678
9000 2.0497883 0.010775465 2.0582862 0.1554819 13883.044
…
39000 2.0454489 0.027371831 2.070548 0.63439734 4320.4557
40000 2.0282281 0.060582915 2.0865575 0.80329021 4225.773
41000 1.9936919 0.090753833 2.0822305 0.861625 4156.8553
42000 2.0315374 0.056152922 2.085433 0.76949757 4090.8558
43000 2.0017193 0.07714716 2.0766423 0.86327754 4048.0323
44000 2.0013392 0.084336331 2.0834518 0.85775653 4017.3438
45000 2.0215616 0.070764789 2.0900802 0.89665952 3952.8586
46000 1.999055 0.095014377 2.0918482 0.9089992 3908.1514
47000 1.9999649 0.094145819 2.0918885 1.0203712 3864.9317
48000 2.0230757 0.06741196 2.0882398 0.95267203 3814.6517
49000 1.9867826 0.10769491 2.09227 1.0992468 3776.65
50000 1.9910828 0.10378077 2.0926513 1.043976 3752.2658
Loop time of 4.82649 on 8 procs for 50000 steps with 900 atoms
Thanks!
Best,
Jing