Dump command in code for previous version not working in current version

Hi everyone. Recently, I attempted to run a LAMMPS input file with Version 29-Oct-20 that a former colleague had successfully run with 9-Dec-14. However, it is not behaving as I expected. I thoroughly read through the code and cross-referenced each line with the LAMMPS manual to ensure that there were no incompatible lines, and did not find anything that raised a red flag.

Here is how the code works: it loops through 100 steps of 1 ps of applying a tensile load in the X-direction (note that the units here are metal), and 10 ps of holding the system at this load. To accomplish this, the code uses two separate run commands.

At the end of holding the system at the load, I would like to output a LAMMPS dump file (i. e. 11 ps, 22 ps, 33 ps). However, the system only outputs dump files for 1, 12, 23, . . . ps (i. e. at the beginning of holding the system at the load). This is true regardless of what interval I ask LAMMPS to output the dump files (i. e. dump deform_tot all custom 11000, dump deform_tot all custom 500).

What modifications do I need to make to my input file for it to output dump files appropriately? I have attached the input file to this post.

40ps_tensile.in (3.2 KB)

Thank you in advance.

Farheen Ahmed

Your input is too convoluted and complex to debug directly. All those many variables make it extremely tedious to figure out what is happening when and where.

If all you want is a dump after each run segment, you can just use the write dump command where you make certain that the time counter is part of the filename and thus they won’t overwrite each other.

For using the dump command, the logic is explained in the documentation. If you have trouble with that, I suggest you create a simplified demo with a similar loop structure but just plain MD based on one of the (simple) examples provided in the LAMMPS examples folder (sans the many variables, too, and with shorter segments). There you can work out the logic and that would be an input that you can post and people can (much more easily) debug.