Help with sliders for visualization

[JJC022]

Hello, whenever I set up model_params in the following way the browser says the parameters are not found when I run the visualization.

from mesa.visualization import SolaraViz, make_space_component, make_plot_component
model_params= {
    "width": {
          "type": "SliderInt",
          "value": 50,
          "label": "Width",
          "min": 5,
          "max": 60,
          "step": 1,
      },
      "height": {
          "type": "SliderInt",
          "value": 50,
          "label": "Height",
          "min": 5,
          "max": 60,
          "step": 1,
      },
     "num_vehicles": {
          "type": "SliderInt",
          "value": 10,
          "label": "Number of vehicles:",
          "min": 1,
          "max": 20,
          "step": 1,
     },
     "num_pedestrians": {
          "type": "SliderInt",
          "value": 10,
          "label": "Number of pedestrians:",
          "min": 1,
          "max": 20,
          "step": 1,
     }
}


traffic_model = PedestrianBicycleModel(width=10, height=10, num_bicycles=10, num_vehicles=10)
SpaceGraph = make_space_component(Pedestrian.agent_portrayal)
# Visualization setup
page = SolaraViz(
    traffic_model, 
    components = [SpaceGraph], 
    model_params=model_params, 
    name = "Please work"
)
page

Thank you for the edits and patience. I checked that the model itself matches up with all of these parameters.

After I run the file using solara, a browser opens running a localhost, and I get the following error message

Traceback (most recent call last):
  File "c:\Users\SmotP\Documents\COGS199\.venv\Lib\site-packages\reacton\core.py", line 1900, in _reconsolidate
    effect()
    ~~~~~~^^
  File "c:\Users\SmotP\Documents\COGS199\.venv\Lib\site-packages\reacton\core.py", line 1131, in __call__
    self._cleanup = self.callable()
                    ~~~~~~~~~~~~~^^
  File "c:\Users\SmotP\Documents\COGS199\.venv\Lib\site-packages\mesa\visualization\solara_viz.py", line 423, in <lambda>
    lambda: _check_model_params(model.value.__class__.__init__, fixed_params),
            ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "c:\Users\SmotP\Documents\COGS199\.venv\Lib\site-packages\mesa\visualization\solara_viz.py", line 476, in _check_model_params
    raise ValueError(f"Missing required model parameter: {name}")
ValueError: Missing required model parameter: width

ps: edited by @quaquel to make code clearer by using github markdown

[Sahil-Chhoker]

Hey @JJC022 can you show a minimal working example that reproduces this error.

[JJC022]

Hi thank you for your response. I am not getting any errors from the command line but I am seeing the error above when Solara opens a browser instance to visualize the model

[quaquel]

can you share the signature of PedestrianBicycleModel.__init__?

[JJC022]

For sure, here is PedestrianBicycleModel.init_

def __init__(self, width, height, num_pedestrians, num_vehicles):
        super().__init__()
        self.grid = MultiGrid(width, height, True)

        self.num_pedestrians = num_pedestrians
        self.num_vehicles= num_vehicles
        
        # Create pedestrians and bicycles
        pedestrians = Pedestrian.create_agents(model= self, n=num_pedestrians)
        cyclists = Bicycle.create_agents(model=self, n=num_vehicles)

        #generate postiions of bicycles at bottom of grid
        x = self.rng.integers(0, self.grid.width, size = (num_vehicles, ))
        y = np.zeros(shape = (num_vehicles, ), dtype= np.int64)

        #place cyclists on grid
        for a, i, j in zip(cyclists, x, y):
            self.grid.place_agent(a, (i,j))

        #generate postiions of pedestrians at left side of grid
        x = np.zeros(shape = (num_pedestrians, ), dtype= np.int64) 
        y = self.rng.integers(0, self.grid.height, size = (num_bicycles, ))

        #place pedestrians on grid
        for a, i , j in zip(pedestrians, x, y):
            self.grid.place_agent(a, (i,j))

[quaquel]

You are using arguments rather than keyword arguments. This most likely explains the problem. You also don't include seed, which is a bad idea because it makes your model not reproducible. Please change it to the signature below and let us know if that solves the problem.

def __init__(self, width=10, height=10, num_pedestrians=1, num_vehicles=1, seed=None):
        super().__init__(seed=seed)