Introduction

Lets look at the absolute simplest simulation you can run using JaxDEM.

Let’s get started!

import jaxdem as jdem

Initialize the Simulation State

First, we create a jaxdem.state.State object. The state object holds all the information of the objects inside the simulation. Lets create a single particle at the origin (0, 0, 0). By default, jaxdem.state.State.create() will set default values for all non-specified attributes.

state = jdem.State.create(pos=[[0.0, 0.0, 0.0]])

Note that we used pos=[[coords]] not pos=[coords]. This is because jaxdem.state.State.create() expects a list of coordinates. Therefore, we must pass a list of lists, even for a single particle. Internally, the coordinates list will be converted to a Jax array.

Initialize the Simulation System

Next, we define our jaxdem.system.System. This object holds all the global parameters and configuration of our simulation. In the same way as state, jaxdem.system.System.create() will use default values for anything we don’t specify. The only requirement is that the dimension of the simulation matches the dimension of the state:

system = jdem.System.create(dim=state.dim)

Run the Simulation

Finally, we drive the simulation by calling jaxdem.system.System.step. We’ll advance the simulation for n_steps time steps:

n_steps = 10
state, system = system.step(state, system, n=n_steps)

Saving the Simulation State

The last thing left to do is to save the simulation:

writer = jdem.VTKWriter()
writer.save(state, system)