Dear Dr. Axel Kohlmeyer and LAMMPS Users,
Hello Dr. Kohlmeyer. Again, thank you so much for all of your time in providing me with advice on LAMMPS.
I recently encountered a problem with bond table command when I am simulating a polymer chain in LAMMPS Version 16Mar2018.
I have attached my small input script (Test.in) that reproduces the issue along with the external data file (polymer.data) and the file necessary for bond table command (P2_P3_Bond_Table.table).
The issue that I am experiencing is when I use bond class2 command with bond coefficients of 4.095 58.818 175.482 146.518 applied on Type 3 bonds, the input script completes its MD run.
However, when I use the bond table command where I manually tabulate the bond energy, length and force for the bond potential having the exact same coefficients that I use for bond class2 (4.095 58.818 175.482 146.518), I receive an error that states “Bond length < table inner cutoff: type 3 length 0.201991.”
I checked the data outputted by thermos command, I see that the pairwise bond energy for the entire system blows up.
Therefore, using bond class2 and bond table using the exact same bond coefficients are giving me two different results when, in fact, they both should be the exactly the same (whether I am using the class2 or manually tabulating the same bond potential profile)
In the small input script, I commented out:
bond_coeff 2*3 class2 4.095 58.818 175.482 146.518
and uncommented
bond_coeff 3 table P2_P3_Bond_Table.table Read_Bond_Table
which results in an error.
However, if I uncommented:
bond_coeff 2*3 class2 4.095 58.818 175.482 146.518
I use bond class2 with prescribed bond coefficients and the input script completes its run.
I would greatly appreciate if I could request for any advice on where I should look.
I truly appreciate your time and effort during your busy schedule.
Thank you.
Sincerely,
Masato Koizumi
P2_P3_Bond_Table.table (41.5 KB)
Test.in (1.16 KB)
polymer.data (6.15 KB)