Passing step number to agent step method

[erissatallan]

My AgentModel class has methods that increment the likelihood that an agent will maintain ownership of an asset in response to incentive given to the agent. One of these methods is

def sigmoidal_incentive_mechanism(self, x):
        self.maintain_probability = 0.1 + (0.9 / 1 + math.exp(-1 * incentive_pool * (self.token_wealth / economy_token_wealth) * x))

One that employs the behavior of the sigmoid function to start this probability at 0.55 and always remain between 0 and 1.
x is meant to capture what number of step the model is being run for, following from this

economyModel = EconomyModel(100, 10, 10)
for run_i in range(10):
    economyModel.step(run_i)

where my EconomyModel class' step method is

def step(self, run_i):
    self.datacollector.collect(self)
    self.schedule.step()

I want to figure out where to pass run_i here so that it is passed to the AgentModel class' step() which in turn passes it to the methods updating the aforementioned probability

def step(self, run_i):
    self.sigmoidal_incentive_mechanism(run_i)

How would one go about that?

[rht]

You don't have to pass the run_i. The scheduler keeps track of the step count (see

mesa/mesa/time.py

Line 83 in 9bc7b1a

self.steps += 1

). You just need to access this scheduler attribute from your agent.

[erissatallan]

Thank you. Could you suggest how to pass EconomyModel attributes to AgentModel during every step? I have some attributes that, unlike the step number, have not been provided for by mesa. So far I haven't thought up any way to do it other than schedule's step() since it is the only method that calls step() in AgentModel.

[tpike3]

If I am understanding correctly, when you set up your AgentModel Class you should also pass in your model. See example below form the mesa tutorial

class MoneyAgent(mesa.Agent):
    """An agent with fixed initial wealth."""

    def __init__(self, unique_id, model):
        super().__init__(unique_id, model)
        self.wealth = 1

Your agent model can then reference any attribute of your EconomyModel by referencing self.model.<model attribute to reference>

[erissatallan]

This works. Thank you.