pyspimosim 1.2.18

SpiMoSim

A python backend for SpiMoSim

https://github.com/pasgra/spimosim can provide a user interface to models written in javascript that run directly in the browser or communicate with a server that runs the model as implemented in this repository.

Example: Ising Model

models/ising_model.py contains an example implementation of the Ising model in python. www/ising contains model specific static files that are directly served by a webserver. The data produced the Ising model implemented in python is send via a websocket to the browser and shown in the browser as a "video" with "up" and "down" spins on a 2D lattice. A plot shows the ratio of "up" and "down" spins, also called "magnetisation".

How to use

Start the python backend (this starts a webserver for serving files and a websocket server to communicate with the simulation):

> python3 -m pyspimosim ising-model

or

> python3 models/ising_model.py

Both do the same.

Open http://localhost:8080/ in your browser or the address printed by the command above.

Different command line flags exist for ports, etc. Run

> python3 -m pyspimosim --help

for details.

Writing custom models

The primary purpose of this repository is not to implement the Ising model but to provide you with everything to create your own "model". A "model" can be a "spin model" like the Ising model or anything else that has some settings and produces data over time that you want to show in a webbrowser. This could be a simulation but also something completely different like a piece of hardware.

Try out the SpiMoSim creator to get a first impression what is possible in SpiMoSim or to even write your whole model in the webbrowser. The SpiMoSim creator is available at http://www.pascalgrafe.net/spimosim/spimosimCreator and also part of the main SpiMoSim repository if you want to run it locally. The SpiMoSim creator is currently limited to models written in Javascript, but replacing a Javascript model with a Python one is simple:

• Load the SimulationBackend module 'server' by adding/uncommenting the folling line in ising/index.html:

  <script src="lib/modules/SimulationBackend/server.js"></script>

• Set the simulation backend to 'server' and set the websocket URL by setting modelConfig.simulation.backend in model-config.js to:

  {
    type: "server",
    url: "ws://localhost:8090"
  }
  

• Write a custom model in python: Create a file with a name ending in -model.py. The file needs to define a Model inherited from pyspimosim.base_model.BaseModel that overwrites the methods

  • async def step(self, vars_config, t)

  or

  • async def steps(self, vars_config, t, protocol, save_interval, next_send_time)

  and

  • async def change_settings(self, model_settings, restart=False).

  Also define the properties

  • name: str
  • multi_step : bool
  • save_state_after_init : bool

  A dataclass ModelBackendSettings is also needed for the model. It should inherit from pyspimosim.base_model.ModelBackendSettings is used to define model specific command line options. pyspimosim.base_model.ModelBackendSettings can also just be imported and left as is.

• Start the server. python3 -m pyspimosim has the optional argument --model_backend_dir to specify where you put your python model. This is not necessary if you make model an executable python script like the Ising model implementation. Use --www_model_root to specify the location of model specific files to be servered by the webserver.