soil/examples/rabbits/improved/rabbit_agents.py

from soil import FSM, state, default_state, BaseAgent, NetworkAgent, Environment
from soil.time import Delta
from enum import Enum
from collections import Counter
import logging
import math


class RabbitEnv(Environment):

    @property
    def num_rabbits(self):
        return self.count_agents(agent_class=Rabbit)

    @property
    def num_males(self):
        return self.count_agents(agent_class=Male)

    @property
    def num_females(self):
        return self.count_agents(agent_class=Female)


class Rabbit(FSM, NetworkAgent):

    sexual_maturity = 30
    life_expectancy = 300
    birth = None

    @property
    def age(self):
        if self.birth is None:
            return None
        return self.now - self.birth

    @default_state
    @state
    def newborn(self):
        self.info('I am a newborn.')
        self.birth = self.now
        self.offspring = 0
        return self.youngling, Delta(self.sexual_maturity - self.age)

    @state
    def youngling(self):
        if self.age >= self.sexual_maturity:
            self.info(f'I am fertile! My age is {self.age}')
            return self.fertile

    @state
    def fertile(self):
        raise Exception("Each subclass should define its fertile state")

    @state
    def dead(self):
        self.die()


class Male(Rabbit):
    max_females = 5
    mating_prob = 0.001

    @state
    def fertile(self):
        if self.age > self.life_expectancy:
            return self.dead

        # Males try to mate
        for f in self.model.agents(agent_class=Female,
                                   state_id=Female.fertile.id,
                                   limit=self.max_females):
            self.debug('FOUND A FEMALE: ', repr(f), self.mating_prob)
            if self.prob(self['mating_prob']):
                f.impregnate(self)
                break  # Do not try to impregnate other females


class Female(Rabbit):
    gestation = 10
    conception = None

    @state
    def fertile(self):
        # Just wait for a Male
        if self.age > self.life_expectancy:
            return self.dead
        if self.conception is not None:
            return self.pregnant

    @property
    def pregnancy(self):
        if self.conception is None:
            return None
        return self.now - self.conception

    def impregnate(self, male):
        self.info(f'impregnated by {repr(male)}')
        self.mate = male
        self.conception = self.now
        self.number_of_babies = int(8+4*self.random.random())

    @state
    def pregnant(self):
        self.debug('I am pregnant')

        if self.age > self.life_expectancy:
            self.info("Dying before giving birth")
            return self.die()

        if self.pregnancy >= self.gestation:
            self.info('Having {} babies'.format(self.number_of_babies))
            for i in range(self.number_of_babies):
                state = {}
                agent_class = self.random.choice([Male, Female])
                child = self.model.add_node(agent_class=agent_class,
                                            **state)
                child.add_edge(self)
                if self.mate:
                    child.add_edge(self.mate)
                    self.mate.offspring += 1
                else:
                    self.debug('The father has passed away')

                self.offspring += 1
            self.mate = None
            return self.fertile

    def die(self):
        if self.pregnancy is not None:
            self.info('A mother has died carrying a baby!!')
        return super().die()


class RandomAccident(BaseAgent):

    def step(self):
        rabbits_alive = self.model.G.number_of_nodes()

        if not rabbits_alive:
            return self.die()

        prob_death = self.model.get('prob_death', 1e-100)*math.floor(math.log10(max(1, rabbits_alive)))
        self.debug('Killing some rabbits with prob={}!'.format(prob_death))
        for i in self.iter_agents(agent_class=Rabbit):
            if i.state_id == i.dead.id:
                continue
            if self.prob(prob_death):
                self.info('I killed a rabbit: {}'.format(i.id))
                rabbits_alive -= 1
                i.die()
        self.debug('Rabbits alive: {}'.format(rabbits_alive))


if __name__ == '__main__':
    from soil import easy
    with easy('rabbits.yml') as sim:
        sim.run()