{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# AGENT #\n", "\n", "An agent, as defined in 2.1 is anything that can perceive its environment through sensors, and act upon that environment through actuators based on its agent program. This can be a dog, robot, or even you. As long as you can perceive the environment and act on it, you are an agent. This notebook will explain how to implement a simple agent, create an environment, and create a program that helps the agent act on the environment based on its percepts.\n", "\n", "Before moving on, review the Agent and Environment classes in [agents.py](https://github.com/aimacode/aima-python/blob/master/agents.py).\n", "\n", "Let's begin by importing all the functions from the agents.py module and creating our first agent - a blind dog." ] }, { "cell_type": "code", "execution_count": 29, "metadata": { "collapsed": false, "scrolled": true }, "outputs": [], "source": [ "from agents import *\n", "\n", "class BlindDog(Agent):\n", " def eat(self, thing):\n", " print(\"Dog: Ate food at {}.\".format(self.location))\n", " \n", " def drink(self, thing):\n", " print(\"Dog: Drank water at {}.\".format( self.location))\n", "\n", "dog = BlindDog()" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "What we have just done is create a dog who can only feel what's in his location (since he's blind), and can eat or drink. Let's see if he's alive..." ] }, { "cell_type": "code", "execution_count": 30, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "True\n" ] } ], "source": [ "print(dog.alive)" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "![Cool dog](https://gifgun.files.wordpress.com/2015/07/wpid-wp-1435860392895.gif = 50x50)\n", "This is our dog. How cool is he? Well, he's hungry and needs to go search for food. For him to do this, we need to give him a program. But before that, let's create a park for our dog to play in." ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# ENVIRONMENT #\n", "\n", "A park is an example of an environment because our dog can perceive and act upon it. The Environment class in agents.py is an abstract class, so we will have to create our own subclass from it before we can use it. The abstract class must contain the following methods:\n", "\n", "
  • percept(self, agent) - returns what the agent perceives
    • \n", "
  • execute_action(self, agent, action) - changes the state of the environment based on what the agent does.
    • " ] }, { "cell_type": "code", "execution_count": 43, "metadata": { "collapsed": false }, "outputs": [], "source": [ "class Food(Thing):\n", " pass\n", "\n", "class Water(Thing):\n", " pass\n", "\n", "class Park(Environment):\n", " '''prints & return a list of things that are in our dog's location'''\n", " def percept(self, agent):\n", " things = self.list_things_at(agent.location)\n", " print(things)\n", " return things\n", " \n", " def execute_action(self, agent, action):\n", " '''changes the state of the environment based on what the agent does.'''\n", " if action == \"move down\":\n", " agent.movedown()\n", " elif action == \"eat\":\n", " items = self.list_things_at(agent.location, tclass=Food)\n", " if len(items) != 0:\n", " if agent.eat(items[0]): #Have the dog pick eat the first item\n", " self.delete_thing(items[0]) #Delete it from the Park after.\n", " elif action == \"drink\":\n", " items = self.list_things_at(agent.location, tclass=Water)\n", " if len(items) != 0:\n", " if agent.drink(items[0]): #Have the dog drink the first item\n", " self.delete_thing(items[0]) #Delete it from the Park after.\n", " \n", " def is_done(self):\n", " '''By default, we're done when we can't find a live agent, \n", " but to prevent killing our cute dog, we will or it with when there is no more food or water'''\n", " no_edibles = not any(isinstance(thing, Food) or isinstance(thing, Water) for thing in self.things)\n", " dead_agents = not any(agent.is_alive() for agent in self.agents)\n", " return dead_agents or no_edibles\n" ] }, { "cell_type": "markdown", "metadata": { "collapsed": true }, "source": [ "# PROGRAM #\n", "Now that we have a Park Class, we need to implement a program module for our dog. A program controls how the dog acts upon it's environment. Our program will be very simple, and is shown in the table below.\n", "\n", " \n", " \n", " \n", " \n", " \n", " \n", " \n", " \n", " \n", " \n", " \n", " \n", " \n", "
    Percept: Feel Food Feel WaterFeel Nothing
    Action: eatdrinkmove up
    \n" ] }, { "cell_type": "code", "execution_count": 44, "metadata": { "collapsed": false }, "outputs": [], "source": [ "class BlindDog(Agent):\n", " location = 1\n", " \n", " def movedown(self):\n", " self.location += 1\n", " \n", " def eat(self, thing):\n", " '''returns True upon success or False otherwise'''\n", " if isinstance(thing, Food):\n", " print(\"Dog: Ate food at {}.\".format(self.location))\n", " return True\n", " return False\n", " \n", " def drink(self, thing):\n", " ''' returns True upon success or False otherwise'''\n", " if isinstance(thing, Water):\n", " print(\"Dog: Drank water at {}.\".format(self.location))\n", " return True\n", " return False\n", " \n", "def program(percepts):\n", " '''Returns an action based on it's percepts'''\n", " for p in percepts:\n", " if isinstance(p, Food):\n", " return 'eat'\n", " elif isinstance(p, Water):\n", " return 'drink'\n", " return 'move down'\n", " \n", " " ] }, { "cell_type": "code", "execution_count": 45, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "[]\n", "[]\n", "[]\n", "[]\n", "[]\n", "[, ]\n", "Dog: Ate food at 5.\n", "[]\n", "[]\n", "[, ]\n", "Dog: Drank water at 7.\n" ] } ], "source": [ "park = Park()\n", "dog = BlindDog(program)\n", "dogfood = Food()\n", "water = Water()\n", "park.add_thing(dog, 0)\n", "park.add_thing(dogfood, 5)\n", "park.add_thing(water, 7)\n", "\n", "park.run(10)" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "That's how easy it is to implement an agent, its program, and environment. But that was a very simple case. What if our environment was 2-Dimentional instead of 1? And what if we had multiple agents?" ] }, { "cell_type": "code", "execution_count": null, "metadata": { "collapsed": true }, "outputs": [], "source": [] } ], "metadata": { "kernelspec": { "display_name": "Python 3", "language": "python", "name": "python3" }, "language_info": { "codemirror_mode": { "name": "ipython", "version": 3 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", "pygments_lexer": "ipython3", "version": "3.5.1" } }, "nbformat": 4, "nbformat_minor": 0 }