def __init__(self, input_dim: int, hidden_dim: int) -> None:
self.input_dim = input_dim
self.hidden_dim = hidden_dim
self.w = random_tensor(hidden_dim, input_dim, init='xavier')
self.u = random_tensor(hidden_dim, hidden_dim, init='xavier')
self.b = random_tensor(hidden_dim)
self.reset_hidden_state()
def __init__(self, num_embeddings: int, embedding_dim: int) -> None:
self.num_embeddings = num_embeddings
self.embedding_dim = embedding_dim
# One vector of size embedding_dim for each desired embedding
self.embeddings = random_tensor(num_embeddings, embedding_dim)
self.grad = zeros_like(self.embeddings)
# Save last input id
self.last_input_id = None
avg_rating = sum(rating.rating for rating in train) / len(train)
baseline_error = sum((rating.rating - avg_rating) ** 2
for rating in test) / len(test)
# Embedding vectors for matrix factorization model
from deep_learning import random_tensor
EMBEDDING_DIM = 2
# Find unique ids
user_ids = {rating.user_id for rating in ratings}
movie_ids = {rating.movie_id for rating in ratings}
# Then create a random vector per id
user_vectors = {user_id: random_tensor(EMBEDDING_DIM)
for user_id in user_ids}
movie_vectors = {movie_id: random_tensor(EMBEDDING_DIM)
for movie_id in movie_ids}
rom typing import List
import tqdm
from vector_operations import dot
def loop(dataset: List[Rating],
learning_rate: float = None) -> None:
with tqdm.tqdm(dataset) as t:
loss = 0.0
for i, rating in enumerate(t):
movie_vector = movie_vectors[rating.movie_id]
user_vector = user_vectors[rating.user_id]
def main():
# Replace this with the locations of your files
# This points to the current directory, modify if your files are elsewhere.
MOVIES = "u.item" # pipe-delimited: movie_id|title|...
RATINGS = "u.data" # tab-delimited: user_id, movie_id, rating, timestamp
from typing import NamedTuple
class Rating(NamedTuple):
user_id: str
movie_id: str
rating: float
import csv
# We specify this encoding to avoid a UnicodeDecodeError.
# see: https://stackoverflow.com/a/53136168/1076346
with open(MOVIES, encoding="iso-8859-1") as f:
reader = csv.reader(f, delimiter="|")
movies = {movie_id: title for movie_id, title, *_ in reader}
# Create a list of [Rating]
with open(RATINGS, encoding="iso-8859-1") as f:
reader = csv.reader(f, delimiter="\t")
ratings = [Rating(user_id, movie_id, float(rating))
for user_id, movie_id, rating, _ in reader]
# 1682 movies rated by 943 users
assert len(movies) == 1682
assert len(list({rating.user_id for rating in ratings})) == 943
import re
# Data structure for accumulating ratings by movie_id
star_wars_ratings = {movie_id: []
for movie_id, title in movies.items()
if re.search("Star Wars|Empire Strikes|Jedi", title)}
# Iterate over ratings, accumulating the Star Wars ones
for rating in ratings:
if rating.movie_id in star_wars_ratings:
star_wars_ratings[rating.movie_id].append(rating.rating)
# Compute the average rating for each movie
avg_ratings = [(sum(title_ratings) / len(title_ratings), movie_id)
for movie_id, title_ratings in star_wars_ratings.items()]
# And then print them in order
for avg_rating, movie_id in sorted(avg_ratings, reverse=True):
print(f"{avg_rating:.2f} {movies[movie_id]}")
import random
random.seed(0)
random.shuffle(ratings)
split1 = int(len(ratings) * 0.7)
split2 = int(len(ratings) * 0.85)
train = ratings[:split1] # 70% of the data
validation = ratings[split1:split2] # 15% of the data
test = ratings[split2:] # 15% of the data
avg_rating = sum(rating.rating for rating in train) / len(train)
baseline_error = sum((rating.rating - avg_rating) ** 2
for rating in test) / len(test)
# This is what we hope to do better than
assert 1.26 < baseline_error < 1.27
# Embedding vectors for matrix factorization model
from deep_learning import random_tensor
EMBEDDING_DIM = 2
# Find unique ids
user_ids = {rating.user_id for rating in ratings}
movie_ids = {rating.movie_id for rating in ratings}
# Then create a random vector per id
user_vectors = {user_id: random_tensor(EMBEDDING_DIM)
for user_id in user_ids}
movie_vectors = {movie_id: random_tensor(EMBEDDING_DIM)
for movie_id in movie_ids}
# Training loop for matrix factorization model
from typing import List
import tqdm
from src.scratch_dir import dot
def loop(dataset: List[Rating],
learning_rate: float = None) -> None:
with tqdm.tqdm(dataset) as t:
loss = 0.0
for i, rating in enumerate(t):
movie_vector = movie_vectors[rating.movie_id]
user_vector = user_vectors[rating.user_id]
predicted = dot(user_vector, movie_vector)
error = predicted - rating.rating
loss += error ** 2
if learning_rate is not None:
# predicted = m_0 * u_0 + ... + m_k * u_k
# So each u_j enters output with coefficent m_j
# and each m_j enters output with coefficient u_j
user_gradient = [error * m_j for m_j in movie_vector]
movie_gradient = [error * u_j for u_j in user_vector]
# Take gradient steps
for j in range(EMBEDDING_DIM):
user_vector[j] -= learning_rate * user_gradient[j]
movie_vector[j] -= learning_rate * movie_gradient[j]
t.set_description(f"avg loss: {loss / (i + 1)}")
learning_rate = 0.05
for epoch in range(20):
learning_rate *= 0.9
print(epoch, learning_rate)
loop(train, learning_rate=learning_rate)
loop(validation)
loop(test)
from working_with_data import pca, transform
original_vectors = [vector for vector in movie_vectors.values()]
components = pca(original_vectors, 2)
ratings_by_movie = defaultdict(list)
for rating in ratings:
ratings_by_movie[rating.movie_id].append(rating.rating)
vectors = [
(movie_id,
sum(ratings_by_movie[movie_id]) / len(ratings_by_movie[movie_id]),
movies[movie_id],
vector)
for movie_id, vector in zip(movie_vectors.keys(),
transform(original_vectors, components))
]
# Print top 25 and bottom 25 by first principal component
print(sorted(vectors, key=lambda v: v[-1][0])[:25])
print(sorted(vectors, key=lambda v: v[-1][0])[-25:])