MLE/04_pacman_rl/reinforcement_learning.py

75 lines
2.2 KiB
Python

"""
Entwickeln Sie einen Reinforcement Learning (RL) Agenten, der in
einem minimalistischen Pacman-Spiel (bereitgestellt auf meiner
Homepage) effektiv Punkte sammelt, während er dem Geist
ausweicht und somit vermeidet gefressen zu werden.
"""
import numpy as np
def q_init():
""" Fill every possible action in every state with a small value for initialization"""
# Configuration
NUM_ACTIONS = 4
INITIAL_Q_VALUE = 1.0 # Small value for initialization
s0_range = range(1, 9)
s1_range = range(1, 4)
s2_range = range(1, 9)
s3_range = range(1, 4)
s_constrained_values = {1, 4, 5, 8}
# The Q-Table dictionary
q_table = {}
# Iterate through all possible combinations of s0, s1, s2, s3
for s0 in s0_range:
for s1 in s1_range:
for s2 in s2_range:
for s3 in s3_range:
# Skip impossible states
if s1 == 2 and s0 not in s_constrained_values:
continue
if s3 == 2 and s2 not in s_constrained_values:
continue
# Assign all possible states a tuple of values
state_key = (s0, s1, s2, s3)
q_table[state_key] = [INITIAL_Q_VALUE] * NUM_ACTIONS
print(f"Total number of valid states initialized: {len(q_table)}") # debugging
# print(list(q_table.items())[:5]) # Uncomment to see the first 5 entries
return q_table
def epsilon_greedy(q, s, epsilon=0.9):
"""
Return which direction Pacman should move to
epsilon-greedy algorithm TBD
"""
q_max = max(q[s])
a = q[s].index(q_max)
return a
def take_action(s, a, labyrinth):
s_new = list(s)
if a == 0:
s_new[0] -= 1
if a == 1:
s_new[0] += 1
if a == 2:
s_new[1] += 1
if a == 3:
s_new[1] -= 1
# consider if there is a point on the field
r = 1 if labyrinth[s_new[0]][s_new[1]] == "." else 0
# consider new distance between Pacman and Ghost
distance = abs(s[0] - s[2]) + abs(s[1] - s[3])
distance_new = abs(s_new[0] - s_new[2]) + abs(s_new[1] - s_new[3])
r += distance_new - distance # adjust this value if necessary
return tuple(s_new), r