I started using LAMMPS 4 months ago and want to simulate semi crystalline polymers. I could not find a compute for examining the crystallinity of a polymer chain… Although my programming skills are not really good I started to program a compute to calculate a bond orientation factor by myself. I started from “compute_coord_atom” and modified the code. So far it seems to be running ok (but still some testing needed on different structures). If there is somebody on the list who is interested in this and would like to have a look on my code, I’d be happy to share, let me know.
Some general questions I could not find an answer in the manual:
How often is a compute invoked. Each timestep, or just when the output is needed for a dump? If it is each timestep, is there a possibility to invoke it just when needed?
Is there the possibility to get a “full” bond list somewhere? I found “atom->bond_atom”, but here I just get the bonds according to the input data file and not a “full” list.
Maybe this is trivial, but I could not find out. Does it make a difference if the function in the compute is called “void ComputeBOFAtom::compute_peratom()” or “void ComputeBOFAtom::compute_local()”? What is the difference?
At the end there is a function “double ComputeBOFAtom::memory_usage()”: Am I right that this function returns the amount of memory that is needed for the per atom vector/array or is it the total memory used for the compute?
I had a look at different computes. Some initialize by “memory->create(…)”, others by “var = new double*[i]”, others just by “double var[i]”. Any recommendation for nice LAMMPS coding?
Dipl.-Ing. Wolfgang Verestek
Institute for Materials Testing, Materials Science and Strength of Materials (IMWF)
Tel: +49 711 685 62583
Fax: +49 711 685 62635
E-Mail: [email protected]…4387…