abpacker

ABPacker is a pattern driven sphere packer. As it is currently written, the code produces config files for the open-source event driven particle simulator DynamO. However the code could be easily modified for other uses

Example usage

$ python3

We can create a DynamO config using the create_config function

>>> from abpacker import create_config

create_config allows us to specify the sphere stacking pattern in terms of the shifted sphere layer positions as described here

We can create an FCC packing simulation config by calling the create_config function and specifying a packing pattern of "ABC"

>>> creat_config("config.xml", 6, 1.2, "ABC")

Here we have specified the number of "packing cells" to be 6 as well as a simulation number density of 1.2. These packing cells consist of a single configuration of 4 particles and are shifted and layered on top of each other according to the packing pattern in order to build the simulation. The "6" means that our simulation will have 6 packing cells in both the x and y directions and double this number (12) in the z direction. The resulting simulation will have 8*7^3 particles.

We can likewise create a simulation with HCP packing by specifying a packing pattern of "AB"

>>> creat_config("config.xml", 7, 1.2, "AB")

We can create any pattern that we want as long as we make sure that we never create a packing pattern with two un-shifted layers next to each other i.e. "ABBC". This will be invalid becuase of the two B rows that are adjacent to eachother. We must also be careful to make sure that the length of the packing pattern is equal to a multiple of the number of packing cells in the z direction (bearing in mind that this will be double the number of specified packing cells).

An example of a more complicated packing pattern is

>>> creat_config("config.xml", 20, 1.2, "ABCABCABAB")

Also bear in mind that the last entry in the packing pattern must be different from the first if the simulation will be periodic.