Snake_AI.py

import torch
import random
import numpy as np
from collections import deque
from game import SnakeGameAI, Direction, Point
from model import Linear_QNet, QTrainer
from helper import plot
import joblib
import os
from pathlib import Path

MAX_MEMORY = 100_000
BATCH_SIZE = 1000
LR = 0.001

class Agent:

    def __init__(self):
        self.n_games = 0
        self.epsilon = 0 
        self.gamma = 0.9 
        self.memory = deque(maxlen=MAX_MEMORY) #
        self.model = Linear_QNet(11, 512, 3)
        self.trainer = QTrainer(self.model, lr=LR, gamma=self.gamma)


    def get_state(self, game):
        head = game.snake[0]
        point_l = Point(head.x - 20, head.y)
        point_r = Point(head.x + 20, head.y)
        point_u = Point(head.x, head.y - 20)
        point_d = Point(head.x, head.y + 20)
        
        dir_l = game.direction == Direction.LEFT
        dir_r = game.direction == Direction.RIGHT
        dir_u = game.direction == Direction.UP
        dir_d = game.direction == Direction.DOWN

        state = [
        
            (dir_r and game.is_collision(point_r)) or 
            (dir_l and game.is_collision(point_l)) or 
            (dir_u and game.is_collision(point_u)) or 
            (dir_d and game.is_collision(point_d)),
       
            (dir_u and game.is_collision(point_r)) or 
            (dir_d and game.is_collision(point_l)) or 
            (dir_l and game.is_collision(point_u)) or 
            (dir_r and game.is_collision(point_d)),
            
            (dir_d and game.is_collision(point_r)) or 
            (dir_u and game.is_collision(point_l)) or 
            (dir_r and game.is_collision(point_u)) or 
            (dir_l and game.is_collision(point_d)),
        
            dir_l,
            dir_r,
            dir_u,
            dir_d,
        
            game.food.x < game.head.x,
            game.food.x > game.head.x, 
            game.food.y < game.head.y, 
            game.food.y > game.head.y 
            ]

        return np.array(state, dtype=int)

    def remember(self, state, action, reward, next_state, done):
        self.memory.append((state, action, reward, next_state, done)) 

    def train_long_memory(self):
        if len(self.memory) > BATCH_SIZE:
            mini_sample = random.sample(self.memory, BATCH_SIZE) 
        else:
            mini_sample = self.memory
        states, actions, rewards, next_states, dones = zip(*mini_sample)
        self.trainer.train_step(states, actions, rewards, next_states, dones)

    def train_short_memory(self, state, action, reward, next_state, done):
        self.trainer.train_step(state, action, reward, next_state, done)

    def get_action(self, state):
        self.epsilon = 80 - self.n_games
        final_move = [0,0,0]
        if random.randint(0, 200) < self.epsilon:
            move = random.randint(0, 2)
            final_move[move] = 1
        else:
            state0 = torch.tensor(state, dtype=torch.float)
            prediction = self.model(state0)
            move = torch.argmax(prediction).item()
            final_move[move] = 1

        return final_move


def train():
    
    plot_scores = []
    plot_mean_scores = []
    total_score = 0
    record = 0
    agent = Agent()
    ans = int(input("Train or Load Model [0,1]"))
    
    while ans not in [0,1]:
        print("invalid input")
        ans = int(input("Train or Load Model [0,1]"))
        
    if ans == 1:
        agent = joblib.load((os.fspath(Path(__file__).resolve().parent / "best.pkl")))

    game = SnakeGameAI() 
        
    while True:
        if game.save == True:
            joblib.dump(agent, (os.fspath(Path(__file__).resolve().parent / "model.pkl")))
        state_old = agent.get_state(game)
        final_move = agent.get_action(state_old)
        reward, done, score = game.play_step(final_move)
        state_new = agent.get_state(game)
        agent.train_short_memory(state_old, final_move, reward, state_new, done)
        agent.remember(state_old, final_move, reward, state_new, done)

        if done:
            game.reset()
            agent.n_games += 1
            agent.train_long_memory()

            if score > record:
                record = score
                joblib.dump(agent,(os.fspath(Path(__file__).resolve().parent / "model.pkl")))
                agent.model.save()

            print('Game', agent.n_games, 'Score', score, 'Record:', record)

            plot_scores.append(score)
            total_score += score
            mean_score = total_score / agent.n_games
            plot_mean_scores.append(mean_score)
            plot(plot_scores, plot_mean_scores)


if __name__ == '__main__':
    train()