From the official guide, the explanation about setting “pair_coeff” command line in granular package,
“”"""
For granular styles there are no additional coefficients to set for each pair of atom types via the pair_coeff command. All settings are global and are made via the pair_style command. However you must still use thepair_coeff for all pairs of granular atom types. For example the command “”"""
It says that the coefficient of interaction model has already been set up in the “pair_style” command line globally. However, in my simulation, there will be two kind of matters, or saying two types of particles, on my opinion, I should set up at least three groups of parameters for the interaction model, right? Why granular package is so unique that define parameters in pair_style command line not the pair_coeff?
From the official guide, the explanation about setting "pair_coeff" command
line in granular package,
"""""
For granular styles there are no additional coefficients to set for each
pair of atom types via the pair_coeff command. All settings are global and
are made via the pair_style command. However you must still use
thepair_coeff for all pairs of granular atom types. For example the command
pair_coeff * *
"""""
It says that the coefficient of interaction model has already been set up in
the "pair_style" command line globally. However, in my simulation, there
will be two kind of matters, or saying two types of particles, on my
opinion, I should set up at least three groups of parameters for the
interaction model, right? Why granular package is so unique that define
parameters in pair_style command line not the pair_coeff?
because that is the model that is being implemented. if you want more
sophisticated granular models, you have to look at the LIGGGHTS
package, which is a fork of LAMMPS with extensions specifically aimed
at granular media.
From the official guide, the explanation about setting “pair_coeff” command line in granular package,
“”"""
For granular styles there are no additional coefficients to set for each pair of atom types via the pair_coeff command. All settings are global and are made via the pair_style command. However you must still use thepair_coeff for all pairs of granular atom types. For example the command
pair_coeff * *
“”"""
It says that the coefficient of interaction model has already been set up in the “pair_style” command line globally. However, in my simulation, there will be two kind of matters, or saying two types of particles, on my opinion, I should set up at least three groups of parameters for the interaction model, right?
If you only want different sizes of particles you can use gran/hertz/history. Otherwise do what Axel said and look at LIGGGHTS.
Why granular package is so unique that define parameters in pair_style command line not the pair_coeff?