When comparing the cell values printed with thermo command and the trajectory files in the atom format, I found different values for lx (if lx = xhi-xlo, and using the conversion in nomenclature for a triclinic system - lattice lengths and angles, when needed).
I tested different triclinic systems and compared the cell values as thermodynamic properties in the log file, with the box parameters printed in the atom format, and with the initial box from the data file. All the other cell parameters match but not the cella or lx for all the tested systems because the xmin value differs from the initial input. This doesn’t occur with a cubic system.
I am using the lammps version of (7 Aug 2019) but I got the same results with recent previous versions. I have attached a log file and the respective trajectory file in the atom format. I have also added the input files that reproduce this simulation.
North Carolina A&T State University
From log file:
Step TotEng Temp Press Volume Cella Cellb Cellc CellAlpha CellBeta CellGamma Density Lx Ly Lz Xy Xz Yz
1 -42.693332 0 796534.02 342.7945 5.48 6.76 9.2799996 90 94.330001 90 2.9491141 5.48 6.76 9.253512 4.14e-16 -0.700648 6.11e-16
From trajectory file:
ITEM: BOX BOUNDS xy xz yz pp pp pp
-7.0064800000000005e-01 5.4800000000000004e+00 4.1400000000000002e-16
0.0000000000000000e+00 6.7600000000000007e+00 -7.0064800000000005e-01
0.0000000000000000e+00 9.2535120000000006e+00 6.1099999999999997e-16
From data file
0.0000 5.48 xlo xhi
0.0000 6.76 ylo yhi
0.0000 9.253512 zlo zhi
4.14E-16 -0.700648 6.11E-16 xy xz yz
log.r_test.MIN (17.3 KB)
r_test.MIN.atom (76.7 KB)
data.r (1.45 KB)
in.r-298K1atm (1.89 KB)
reax.ffield_CaSiAlO_Pitman (20.3 KB)
lmp_control (1009 Bytes)