Mesa Interactive

Overview

Mesa Interactive is a specialized Python package designed to provide dynamic visualization and interaction capabilities for Mesa models. It extends the functionalities of the Mesa framework for agent-based modeling.

Quick Installation

To quickly install the package, open your terminal and run:

pip install mesa_interactive

Tutorial: Visualizing the Schelling Segregation Model

This section provides a step-by-step walkthrough to visualize a Schelling Segregation model using Mesa Interactive.

Prerequisites

Ensure that you have mesa-models installed. If not, run the following command:

pip install -U -e git+https://github.com/projectmesa/mesa-examples#egg=mesa-models

Importing Dependencies

Import the essential libraries as follows:

import solara
from mesa_models.schelling.model import Schelling

from mesa_interactive import MesaInteractive, slide, static
from mesa_interactive.components import create_chart, create_grid, create_markdown

Building Components

1. Instructions: Add Markdown instructions. We use the static helper function, since it doesn't rely on model parameters.

Instructions = static(solara.Markdown("Click on an agent to switch its type."))

2. GridView: Construct a grid view, enabling a switch_agent_type function on agent click.

def switch_agent_type(model, x, y):
    agent = model.grid.get_cell_list_contents([(x, y)])[0]
    agent.type = 1 - agent.type

GridView = create_grid(color="type", on_click=switch_agent_type)

3. HappyCount: Display the number of satisfied agents via a Markdown component.

HappyCount = create_markdown(
    lambda model: f"**Happy Agents: {model.happy} of {len(model.schedule.agents)}**"
)

4. HappyChart: Implement a time-series chart to track the number of happy agents.

HappyChart = create_chart(variables=["happy"], "Happy Agents")

Configuring Model Parameters

Define user-adjustable model parameters using default values and the slide helper functions. It works like the built-in range function but supports arbitrary steps and a default value.

model_params = {
    "width": 20,
    "height": 20,
    "density": slide(0, 1, 0.1, default=0.65),
    "minority_pc": slide(0, 1, 0.05, default=0.2),
    "homophily": slide(0, 8, 1, default=3),
}

Creating the Interactive Page

1. Initialize the Mesa Interactive interface with the Schelling model, model parameters, and assembled components.

page = MesaInteractive(
    Schelling,
    model_params,
    components=[HappyCount, Instructions, GridView, HappyChart],
    name="Schelling",
    show_dataframe="model",
)

2. To render your visulazation save your python file as app.py and from a terminal run

solara run app.py

Alternatively you can but everything in a Jupyter notebook and simply call

page

to show the visualization.

Now you have built a fully interactive visualization for the Schelling Segregation model!