cse151b-final-project/gym_wordle/wordle.py
2024-03-18 11:25:14 -07:00

341 lines
12 KiB
Python

import gymnasium as gym
import numpy as np
import numpy.typing as npt
from sty import fg, bg, ef, rs
from collections import Counter
from gym_wordle.utils import to_english, to_array, get_words
from typing import Optional
from collections import defaultdict
class WordList(gym.spaces.Discrete):
"""Super class for defining a space of valid words according to a specified
list.
The space is a subclass of gym.spaces.Discrete, where each element
corresponds to an index of a valid word in the word list. The obfuscation
is necessary for more direct implementation of RL algorithms, which expect
spaces of less sophisticated form.
In addition to the default methods of the Discrete space, it implements
a __getitem__ method for easy index lookup, and an index_of method to
convert potential words into their corresponding index (if they exist).
"""
def __init__(self, words: npt.NDArray[np.int64], **kwargs):
"""
Args:
words: Collection of words in array form with shape (_, 5), where
each word is a row of the array. Each array element is an integer
between 0,...,26 (inclusive).
kwargs: See documentation for gym.spaces.MultiDiscrete
"""
super().__init__(words.shape[0], **kwargs)
self.words = words
def __getitem__(self, index: int) -> npt.NDArray[np.int64]:
"""Obtains the (int-encoded) word associated with the given index.
Args:
index: Index for the list of words.
Returns:
Associated word at the position specified by index.
"""
return self.words[index]
def index_of(self, word: npt.NDArray[np.int64]) -> int:
"""Given a word, determine its index in the list (if it exists),
otherwise returning -1 if no index exists.
Args:
word: Word to find in the word list.
Returns:
The index of the given word if it exists, otherwise -1.
"""
try:
index, = np.nonzero((word == self.words).all(axis=1))
return index[0]
except:
return -1
class SolutionList(WordList):
"""Space for *solution* words to the Wordle environment.
In the game Wordle, there are two different collections of words:
* "guesses", which the game accepts as valid words to use to guess the
answer.
* "solutions", which the game uses to choose solutions from.
Of course, the set of solutions is a strict subset of the set of guesses.
This class represents the set of solution words.
"""
def __init__(self, **kwargs):
"""
Args:
kwargs: See documentation for gym.spaces.MultiDiscrete
"""
words = get_words('solution')
super().__init__(words, **kwargs)
class WordleObsSpace(gym.spaces.Box):
"""Implementation of the state (observation) space in terms of gym
primitives, in this case, gym.spaces.Box.
The Wordle observation space can be thought of as a 6x5 array with two
channels:
- the character channel, indicating which characters are placed on the
board (unfilled rows are marked with the empty character, 0)
- the flag channel, indicating the in-game information associated with
each character's placement (green highlight, yellow highlight, etc.)
where there are 6 rows, one for each turn in the game, and 5 columns, since
the solution will always be a word of length 5.
For simplicity, and compatibility with stable_baselines algorithms,
this multichannel is modeled as a 6x10 array, where the two channels are
horizontally appended (along columns). Thus each row in the observation
should be interpreted as c0 c1 c2 c3 c4 f0 f1 f2 f3 f4 when the word is
c0...c4 and its associated flags are f0...f4.
"""
def __init__(self, **kwargs):
self.n_rows = 6
self.n_cols = 5
self.max_char = 26
self.max_flag = 4
low = np.zeros((self.n_rows, 2*self.n_cols))
high = np.c_[np.full((self.n_rows, self.n_cols), self.max_char),
np.full((self.n_rows, self.n_cols), self.max_flag)]
super().__init__(low, high, dtype=np.int64, **kwargs)
class GuessList(WordList):
"""Space for *guess* words to the Wordle environment.
This class represents the set of guess words.
"""
def __init__(self, **kwargs):
"""
Args:
kwargs: See documentation for gym.spaces.MultiDiscrete
"""
words = get_words('guess')
super().__init__(words, **kwargs)
class WordleEnv(gym.Env):
metadata = {'render.modes': ['human']}
# Character flag codes
no_char = 0
right_pos = 1
wrong_pos = 2
wrong_char = 3
def __init__(self):
super().__init__()
self.action_space = GuessList()
self.solution_space = SolutionList()
self.observation_space = WordleObsSpace()
self._highlights = {
self.right_pos: (bg.green, bg.rs),
self.wrong_pos: (bg.yellow, bg.rs),
self.wrong_char: ('', ''),
self.no_char: ('', ''),
}
self.n_rounds = 6
self.n_letters = 5
self.info = {
'correct': False,
'guesses': set(),
'known_positions': np.full(5, -1), # -1 for unknown, else letter index
'known_letters': set(), # Letters known to be in the word
'not_in_word': set(), # Letters known not to be in the word
'tried_positions': defaultdict(set) # Positions tried for each letter
}
def _highlighter(self, char: str, flag: int) -> str:
"""Terminal renderer functionality. Properly highlights a character
based on the flag associated with it.
Args:
char: Character in question.
flag: Associated flag, one of:
- 0: no character (render no background)
- 1: right position (render green background)
- 2: wrong position (render yellow background)
- 3: wrong character (render no background)
Returns:
Correct ASCII sequence producing the desired character in the
correct background.
"""
front, back = self._highlights[flag]
return front + char + back
def reset(self, seed=None, options=None):
"""Reset the environment to an initial state and returns an initial
observation.
Note: The observation space instance should be a Box space.
Returns:
state (object): The initial observation of the space.
"""
self.round = 0
self.solution = self.solution_space.sample()
self.soln_hash = set(self.solution_space[self.solution])
self.state = np.zeros((self.n_rounds, 2 * self.n_letters), dtype=np.int64)
self.info = {
'correct': False,
'guesses': set(),
'known_positions': np.full(5, -1),
'known_letters': set(),
'not_in_word': set(),
'tried_positions': defaultdict(set)
}
self.simulate_first_guess()
return self.state, self.info
def simulate_first_guess(self):
fixed_first_guess = "rates"
fixed_first_guess_array = to_array(fixed_first_guess)
# Simulate the feedback for each letter in the fixed first guess
feedback = np.zeros(self.n_letters, dtype=int) # Initialize feedback array
for i, letter in enumerate(fixed_first_guess_array):
if letter in self.solution_space[self.solution]:
if letter == self.solution_space[self.solution][i]:
feedback[i] = 1 # Correct position
else:
feedback[i] = 2 # Correct letter, wrong position
else:
feedback[i] = 3 # Letter not in word
# Update the state to reflect the fixed first guess and its feedback
self.state[0, :self.n_letters] = fixed_first_guess_array
self.state[0, self.n_letters:] = feedback
# Update self.info based on the feedback
for i, flag in enumerate(feedback):
if flag == self.right_pos:
# Mark letter as correctly placed
self.info['known_positions'][i] = fixed_first_guess_array[i]
elif flag == self.wrong_pos:
# Note the letter is in the word but in a different position
self.info['known_letters'].add(fixed_first_guess_array[i])
elif flag == self.wrong_char:
# Note the letter is not in the word
self.info['not_in_word'].add(fixed_first_guess_array[i])
# Since we're simulating the first guess, increment the round counter
self.round = 1
def render(self, mode: str = 'human'):
"""Renders the Wordle environment.
Currently supported render modes:
- human: renders the Wordle game to the terminal.
Args:
mode: the mode to render with.
"""
if mode == 'human':
for row in self.state:
text = ''.join(map(
self._highlighter,
to_english(row[:self.n_letters]).upper(),
row[self.n_letters:]
))
print(text)
else:
super().render(mode=mode)
def step(self, action):
assert self.action_space.contains(action), 'Invalid word!'
guessed_word = self.action_space[action]
solution_word = self.solution_space[self.solution]
reward = 0
correct_guess = np.array_equal(guessed_word, solution_word)
# Initialize flags for current guess
current_flags = np.full(self.n_letters, self.wrong_char)
# Track newly discovered information
new_info = False
for i in range(self.n_letters):
guessed_letter = guessed_word[i]
if guessed_letter in solution_word:
# Penalize for reusing a letter found to not be in the word
if guessed_letter in self.info['not_in_word']:
reward -= 2
# Handle correct letter in the correct position
if guessed_letter == solution_word[i]:
current_flags[i] = self.right_pos
if self.info['known_positions'][i] != guessed_letter:
reward += 10 # Large reward for new correct placement
new_info = True
self.info['known_positions'][i] = guessed_letter
else:
reward += 20 # Large reward for repeating correct placement
else:
current_flags[i] = self.wrong_pos
if guessed_letter not in self.info['known_letters'] or i not in self.info['tried_positions'][guessed_letter]:
reward += 10 # Reward for guessing a letter in a new position
new_info = True
else:
reward -= 20 # Penalize for not leveraging known information
self.info['known_letters'].add(guessed_letter)
self.info['tried_positions'][guessed_letter].add(i)
else:
# New incorrect letter
if guessed_letter not in self.info['not_in_word']:
reward -= 2 # Penalize for guessing a letter not in the word
self.info['not_in_word'].add(guessed_letter)
new_info = True
else:
reward -= 15 # Larger penalty for repeating an incorrect letter
# Update observation state with the current guess and flags
self.state[self.round, :self.n_letters] = guessed_word
self.state[self.round, self.n_letters:] = current_flags
# Check if the game is over
done = self.round == self.n_rounds - 1 or correct_guess
self.info['correct'] = correct_guess
if correct_guess:
reward += 100 # Major reward for winning
elif done:
reward -= 50 # Penalty for losing without using new information effectively
elif not new_info:
reward -= 10 # Penalty if no new information was used in this guess
self.round += 1
return self.state, reward, done, False, self.info