I am simulating granular molecules being first poured into a periodic box, and then compressed. I have been having a lot of trouble with differences between the Windows, Linux and Mac versions of LAMMPS, but I have found one in particular that I cannot seem to find a workaround for.
I want to pour first spheres, and then a granular molecule “m1” and then a second granular molecule “m2.” In the Mac version of LAMMPS, I can accomplish this with the following commands:
molecule m1 molecule1.shape
group mol1_group type molecule m1
fix rm1 mol1_group rigid/small molecule mol m1
molecule m2 molecule2.shape
group mol2_group type molecule m2
fix rm2 mol2_group rigid/small molecule mol m2
I can then pour these molecules later. Initially, each group has 0 members, and only acquires them as I pour them into the box. For my second molecule, I do the same thing, first making a group with 0 members and then fixing this group “rigid/small” and then pouring later.
This procedure only works on the Mac version, and not the Windows or Linux versions. I cannot seem to use create_atoms and then fix this rigid as a molecule either.
How can I pour multiple granular molecules, defined by multiple molecule files and fix rigid/small, into the same box? I cannot figure this out. Any help would be greatly appreciated.
Thank you very much,