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Upload comprehensive_recommendation_system.py
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comprehensive_recommendation_system.py
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|
| 1 |
+
"""
|
| 2 |
+
Comprehensive Movie Recommendation System
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| 3 |
+
========================================
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| 4 |
+
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| 5 |
+
This system implements multiple recommendation approaches:
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| 6 |
+
1. User-based Collaborative Filtering
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| 7 |
+
2. Item-based Collaborative Filtering
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| 8 |
+
3. Matrix Factorization (SVD)
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| 9 |
+
4. Neural Embeddings (Deep Learning)
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| 10 |
+
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| 11 |
+
Author: DataSynthis ML Team
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| 12 |
+
Date: 2024
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| 13 |
+
"""
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| 14 |
+
|
| 15 |
+
import pandas as pd
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| 16 |
+
import numpy as np
|
| 17 |
+
import pickle
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| 18 |
+
import os
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| 19 |
+
from typing import List, Tuple, Dict, Optional
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| 20 |
+
from sklearn.metrics.pairwise import cosine_similarity
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| 21 |
+
from sklearn.decomposition import TruncatedSVD
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| 22 |
+
from sklearn.neural_network import MLPRegressor
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| 23 |
+
from sklearn.preprocessing import StandardScaler
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| 24 |
+
from sklearn.model_selection import train_test_split
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| 25 |
+
from sklearn.metrics import mean_squared_error, mean_absolute_error
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| 26 |
+
import matplotlib.pyplot as plt
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| 27 |
+
import seaborn as sns
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| 28 |
+
import warnings
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| 29 |
+
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| 30 |
+
warnings.filterwarnings('ignore')
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| 31 |
+
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| 32 |
+
class ComprehensiveRecommendationSystem:
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| 33 |
+
"""
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| 34 |
+
Comprehensive recommendation system implementing multiple approaches
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| 35 |
+
"""
|
| 36 |
+
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| 37 |
+
def __init__(self, data_path: str = None):
|
| 38 |
+
"""
|
| 39 |
+
Initialize the recommendation system
|
| 40 |
+
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| 41 |
+
Args:
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| 42 |
+
data_path: Path to the MovieLens dataset directory
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| 43 |
+
"""
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| 44 |
+
self.data_path = data_path
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| 45 |
+
self.ratings = None
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| 46 |
+
self.movies = None
|
| 47 |
+
self.user_item_matrix = None
|
| 48 |
+
self.user_similarity_matrix = None
|
| 49 |
+
self.item_similarity_matrix = None
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| 50 |
+
self.svd_model = None
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| 51 |
+
self.neural_model = None
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| 52 |
+
self.scaler = None
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| 53 |
+
self.user_means = None
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| 54 |
+
self.item_means = None
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| 55 |
+
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| 56 |
+
def load_data(self, ratings_file: str, movies_file: str):
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| 57 |
+
"""
|
| 58 |
+
Load and preprocess the MovieLens dataset
|
| 59 |
+
|
| 60 |
+
Args:
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| 61 |
+
ratings_file: Path to ratings file
|
| 62 |
+
movies_file: Path to movies file
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| 63 |
+
"""
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| 64 |
+
print("Loading MovieLens dataset...")
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| 65 |
+
|
| 66 |
+
# Load ratings data - handle both CSV and tab-separated formats
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| 67 |
+
if ratings_file.endswith('.csv'):
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| 68 |
+
self.ratings = pd.read_csv(ratings_file)
|
| 69 |
+
# Rename columns to standard format
|
| 70 |
+
if 'userId' in self.ratings.columns:
|
| 71 |
+
self.ratings = self.ratings.rename(columns={'userId': 'user_id', 'movieId': 'movie_id'})
|
| 72 |
+
else:
|
| 73 |
+
# Handle tab-separated format (ml-100k)
|
| 74 |
+
self.ratings = pd.read_csv(
|
| 75 |
+
ratings_file,
|
| 76 |
+
sep="\t",
|
| 77 |
+
names=["user_id", "movie_id", "rating", "timestamp"]
|
| 78 |
+
)
|
| 79 |
+
|
| 80 |
+
# Load movies data - handle both CSV and pipe-separated formats
|
| 81 |
+
if movies_file.endswith('.csv'):
|
| 82 |
+
self.movies = pd.read_csv(movies_file)
|
| 83 |
+
# Rename columns to standard format
|
| 84 |
+
if 'movieId' in self.movies.columns:
|
| 85 |
+
self.movies = self.movies.rename(columns={'movieId': 'movie_id'})
|
| 86 |
+
# Select relevant columns for movies
|
| 87 |
+
if 'title' in self.movies.columns:
|
| 88 |
+
self.movies = self.movies[['movie_id', 'title']]
|
| 89 |
+
else:
|
| 90 |
+
# Fallback to first two columns if title column not found
|
| 91 |
+
self.movies = self.movies.iloc[:, [0, 1]]
|
| 92 |
+
self.movies.columns = ["movie_id", "title"]
|
| 93 |
+
else:
|
| 94 |
+
# Handle pipe-separated format (ml-100k)
|
| 95 |
+
self.movies = pd.read_csv(
|
| 96 |
+
movies_file,
|
| 97 |
+
sep="|",
|
| 98 |
+
encoding="latin-1",
|
| 99 |
+
header=None
|
| 100 |
+
)
|
| 101 |
+
# Select relevant columns for movies
|
| 102 |
+
self.movies = self.movies[[0, 1]]
|
| 103 |
+
self.movies.columns = ["movie_id", "title"]
|
| 104 |
+
|
| 105 |
+
print(f"Ratings shape: {self.ratings.shape}")
|
| 106 |
+
print(f"Movies shape: {self.movies.shape}")
|
| 107 |
+
print(f"Unique users: {self.ratings['user_id'].nunique()}")
|
| 108 |
+
print(f"Unique movies: {self.movies['movie_id'].nunique()}")
|
| 109 |
+
print(f"Rating range: {self.ratings['rating'].min()} - {self.ratings['rating'].max()}")
|
| 110 |
+
|
| 111 |
+
# Create user-item matrix
|
| 112 |
+
self._create_user_item_matrix()
|
| 113 |
+
|
| 114 |
+
def _create_user_item_matrix(self):
|
| 115 |
+
"""Create user-item rating matrix"""
|
| 116 |
+
print("Creating user-item matrix...")
|
| 117 |
+
self.user_item_matrix = self.ratings.pivot_table(
|
| 118 |
+
index="user_id",
|
| 119 |
+
columns="movie_id",
|
| 120 |
+
values="rating"
|
| 121 |
+
).fillna(0)
|
| 122 |
+
|
| 123 |
+
print(f"User-Item Matrix shape: {self.user_item_matrix.shape}")
|
| 124 |
+
print(f"Sparsity: {(1 - (self.user_item_matrix != 0).sum().sum() / self.user_item_matrix.size) * 100:.2f}%")
|
| 125 |
+
|
| 126 |
+
def train_user_based_cf(self):
|
| 127 |
+
"""Train user-based collaborative filtering"""
|
| 128 |
+
print("Training user-based collaborative filtering...")
|
| 129 |
+
|
| 130 |
+
# Compute user similarity matrix
|
| 131 |
+
self.user_similarity_matrix = cosine_similarity(self.user_item_matrix)
|
| 132 |
+
|
| 133 |
+
# Calculate user means for bias correction
|
| 134 |
+
self.user_means = self.user_item_matrix.mean(axis=1)
|
| 135 |
+
|
| 136 |
+
print("User-based CF trained successfully!")
|
| 137 |
+
|
| 138 |
+
def train_item_based_cf(self):
|
| 139 |
+
"""Train item-based collaborative filtering"""
|
| 140 |
+
print("Training item-based collaborative filtering...")
|
| 141 |
+
|
| 142 |
+
# Compute item similarity matrix
|
| 143 |
+
self.item_similarity_matrix = cosine_similarity(self.user_item_matrix.T)
|
| 144 |
+
|
| 145 |
+
# Calculate item means for bias correction
|
| 146 |
+
self.item_means = self.user_item_matrix.mean(axis=0)
|
| 147 |
+
|
| 148 |
+
print("Item-based CF trained successfully!")
|
| 149 |
+
|
| 150 |
+
def train_svd(self, n_components: int = 50):
|
| 151 |
+
"""Train SVD matrix factorization"""
|
| 152 |
+
print(f"Training SVD with {n_components} components...")
|
| 153 |
+
|
| 154 |
+
# Create a copy of the matrix for SVD
|
| 155 |
+
matrix_for_svd = self.user_item_matrix.copy()
|
| 156 |
+
|
| 157 |
+
# Replace 0s with user means for proper SVD
|
| 158 |
+
user_means = matrix_for_svd.mean(axis=1)
|
| 159 |
+
for user_id in matrix_for_svd.index:
|
| 160 |
+
user_ratings = matrix_for_svd.loc[user_id]
|
| 161 |
+
zero_mask = user_ratings == 0
|
| 162 |
+
matrix_for_svd.loc[user_id, zero_mask] = user_means[user_id]
|
| 163 |
+
|
| 164 |
+
# Apply SVD
|
| 165 |
+
self.svd_model = TruncatedSVD(n_components=n_components, random_state=42)
|
| 166 |
+
self.svd_model.fit(matrix_for_svd)
|
| 167 |
+
|
| 168 |
+
print("SVD trained successfully!")
|
| 169 |
+
|
| 170 |
+
def train_neural_embeddings(self, hidden_layers: Tuple = (100, 50), max_iter: int = 100):
|
| 171 |
+
"""Train neural network for embeddings"""
|
| 172 |
+
print("Training neural embeddings...")
|
| 173 |
+
|
| 174 |
+
# Prepare data for neural network
|
| 175 |
+
X = []
|
| 176 |
+
y = []
|
| 177 |
+
|
| 178 |
+
for user_id in self.user_item_matrix.index:
|
| 179 |
+
for movie_id in self.user_item_matrix.columns:
|
| 180 |
+
rating = self.user_item_matrix.loc[user_id, movie_id]
|
| 181 |
+
if rating > 0: # Only use actual ratings
|
| 182 |
+
X.append([user_id, movie_id])
|
| 183 |
+
y.append(rating)
|
| 184 |
+
|
| 185 |
+
X = np.array(X)
|
| 186 |
+
y = np.array(y)
|
| 187 |
+
|
| 188 |
+
# Scale features
|
| 189 |
+
self.scaler = StandardScaler()
|
| 190 |
+
X_scaled = self.scaler.fit_transform(X)
|
| 191 |
+
|
| 192 |
+
# Train neural network
|
| 193 |
+
self.neural_model = MLPRegressor(
|
| 194 |
+
hidden_layer_sizes=hidden_layers,
|
| 195 |
+
max_iter=max_iter,
|
| 196 |
+
random_state=42
|
| 197 |
+
)
|
| 198 |
+
|
| 199 |
+
self.neural_model.fit(X_scaled, y)
|
| 200 |
+
|
| 201 |
+
print("Neural embeddings trained successfully!")
|
| 202 |
+
|
| 203 |
+
def recommend_movies_user_based(self, user_id: int, N: int = 10, top_k: int = 10) -> pd.DataFrame:
|
| 204 |
+
"""
|
| 205 |
+
Generate recommendations using user-based collaborative filtering
|
| 206 |
+
|
| 207 |
+
Args:
|
| 208 |
+
user_id: ID of the user to recommend for
|
| 209 |
+
N: Number of movies to recommend
|
| 210 |
+
top_k: Number of similar users to consider
|
| 211 |
+
|
| 212 |
+
Returns:
|
| 213 |
+
DataFrame with recommended movies
|
| 214 |
+
"""
|
| 215 |
+
if user_id not in self.user_item_matrix.index:
|
| 216 |
+
return pd.DataFrame(columns=['movie_id', 'title', 'predicted_rating'])
|
| 217 |
+
|
| 218 |
+
# Get user's ratings
|
| 219 |
+
user_ratings = self.user_item_matrix.loc[user_id]
|
| 220 |
+
rated_movies = set(user_ratings[user_ratings > 0].index)
|
| 221 |
+
|
| 222 |
+
# Get all movies
|
| 223 |
+
all_movies = set(self.user_item_matrix.columns)
|
| 224 |
+
unrated_movies = all_movies - rated_movies
|
| 225 |
+
|
| 226 |
+
if not unrated_movies:
|
| 227 |
+
return pd.DataFrame(columns=['movie_id', 'title', 'predicted_rating'])
|
| 228 |
+
|
| 229 |
+
# Get similar users
|
| 230 |
+
user_idx = list(self.user_item_matrix.index).index(user_id)
|
| 231 |
+
similarities = self.user_similarity_matrix[user_idx]
|
| 232 |
+
similar_users_idx = np.argsort(similarities)[::-1][1:top_k+1]
|
| 233 |
+
|
| 234 |
+
# Predict ratings for unrated movies
|
| 235 |
+
predictions = []
|
| 236 |
+
for movie_id in unrated_movies:
|
| 237 |
+
predicted_rating = self._predict_rating_user_based(user_id, movie_id, similar_users_idx)
|
| 238 |
+
if predicted_rating > 0:
|
| 239 |
+
predictions.append({
|
| 240 |
+
'movie_id': movie_id,
|
| 241 |
+
'predicted_rating': predicted_rating
|
| 242 |
+
})
|
| 243 |
+
|
| 244 |
+
if not predictions:
|
| 245 |
+
return pd.DataFrame(columns=['movie_id', 'title', 'predicted_rating'])
|
| 246 |
+
|
| 247 |
+
# Sort by predicted rating and get top-N
|
| 248 |
+
predictions_df = pd.DataFrame(predictions)
|
| 249 |
+
predictions_df = predictions_df.sort_values('predicted_rating', ascending=False).head(N)
|
| 250 |
+
|
| 251 |
+
# Merge with movie information
|
| 252 |
+
recommendations = predictions_df.merge(
|
| 253 |
+
self.movies[['movie_id', 'title']],
|
| 254 |
+
on='movie_id',
|
| 255 |
+
how='left'
|
| 256 |
+
)
|
| 257 |
+
|
| 258 |
+
return recommendations[['movie_id', 'title', 'predicted_rating']]
|
| 259 |
+
|
| 260 |
+
def recommend_movies_item_based(self, user_id: int, N: int = 10, top_k: int = 10) -> pd.DataFrame:
|
| 261 |
+
"""
|
| 262 |
+
Generate recommendations using item-based collaborative filtering
|
| 263 |
+
|
| 264 |
+
Args:
|
| 265 |
+
user_id: ID of the user to recommend for
|
| 266 |
+
N: Number of movies to recommend
|
| 267 |
+
top_k: Number of similar items to consider
|
| 268 |
+
|
| 269 |
+
Returns:
|
| 270 |
+
DataFrame with recommended movies
|
| 271 |
+
"""
|
| 272 |
+
if user_id not in self.user_item_matrix.index:
|
| 273 |
+
return pd.DataFrame(columns=['movie_id', 'title', 'predicted_rating'])
|
| 274 |
+
|
| 275 |
+
# Get user's ratings
|
| 276 |
+
user_ratings = self.user_item_matrix.loc[user_id]
|
| 277 |
+
rated_movies = set(user_ratings[user_ratings > 0].index)
|
| 278 |
+
|
| 279 |
+
# Get all movies
|
| 280 |
+
all_movies = set(self.user_item_matrix.columns)
|
| 281 |
+
unrated_movies = all_movies - rated_movies
|
| 282 |
+
|
| 283 |
+
if not unrated_movies:
|
| 284 |
+
return pd.DataFrame(columns=['movie_id', 'title', 'predicted_rating'])
|
| 285 |
+
|
| 286 |
+
# Predict ratings for unrated movies
|
| 287 |
+
predictions = []
|
| 288 |
+
for movie_id in unrated_movies:
|
| 289 |
+
predicted_rating = self._predict_rating_item_based(user_id, movie_id, top_k)
|
| 290 |
+
if predicted_rating > 0:
|
| 291 |
+
predictions.append({
|
| 292 |
+
'movie_id': movie_id,
|
| 293 |
+
'predicted_rating': predicted_rating
|
| 294 |
+
})
|
| 295 |
+
|
| 296 |
+
if not predictions:
|
| 297 |
+
return pd.DataFrame(columns=['movie_id', 'title', 'predicted_rating'])
|
| 298 |
+
|
| 299 |
+
# Sort by predicted rating and get top-N
|
| 300 |
+
predictions_df = pd.DataFrame(predictions)
|
| 301 |
+
predictions_df = predictions_df.sort_values('predicted_rating', ascending=False).head(N)
|
| 302 |
+
|
| 303 |
+
# Merge with movie information
|
| 304 |
+
recommendations = predictions_df.merge(
|
| 305 |
+
self.movies[['movie_id', 'title']],
|
| 306 |
+
on='movie_id',
|
| 307 |
+
how='left'
|
| 308 |
+
)
|
| 309 |
+
|
| 310 |
+
return recommendations[['movie_id', 'title', 'predicted_rating']]
|
| 311 |
+
|
| 312 |
+
def recommend_movies_svd(self, user_id: int, N: int = 10) -> pd.DataFrame:
|
| 313 |
+
"""
|
| 314 |
+
Generate recommendations using SVD matrix factorization
|
| 315 |
+
|
| 316 |
+
Args:
|
| 317 |
+
user_id: ID of the user to recommend for
|
| 318 |
+
N: Number of movies to recommend
|
| 319 |
+
|
| 320 |
+
Returns:
|
| 321 |
+
DataFrame with recommended movies
|
| 322 |
+
"""
|
| 323 |
+
if user_id not in self.user_item_matrix.index:
|
| 324 |
+
return pd.DataFrame(columns=['movie_id', 'title', 'predicted_rating'])
|
| 325 |
+
|
| 326 |
+
# Get user's ratings
|
| 327 |
+
user_ratings = self.user_item_matrix.loc[user_id]
|
| 328 |
+
rated_movies = set(user_ratings[user_ratings > 0].index)
|
| 329 |
+
|
| 330 |
+
# Get all movies
|
| 331 |
+
all_movies = set(self.user_item_matrix.columns)
|
| 332 |
+
unrated_movies = all_movies - rated_movies
|
| 333 |
+
|
| 334 |
+
if not unrated_movies:
|
| 335 |
+
return pd.DataFrame(columns=['movie_id', 'title', 'predicted_rating'])
|
| 336 |
+
|
| 337 |
+
# Predict ratings for unrated movies
|
| 338 |
+
predictions = []
|
| 339 |
+
for movie_id in unrated_movies:
|
| 340 |
+
predicted_rating = self._predict_rating_svd(user_id, movie_id)
|
| 341 |
+
if predicted_rating > 0:
|
| 342 |
+
predictions.append({
|
| 343 |
+
'movie_id': movie_id,
|
| 344 |
+
'predicted_rating': predicted_rating
|
| 345 |
+
})
|
| 346 |
+
|
| 347 |
+
if not predictions:
|
| 348 |
+
return pd.DataFrame(columns=['movie_id', 'title', 'predicted_rating'])
|
| 349 |
+
|
| 350 |
+
# Sort by predicted rating and get top-N
|
| 351 |
+
predictions_df = pd.DataFrame(predictions)
|
| 352 |
+
predictions_df = predictions_df.sort_values('predicted_rating', ascending=False).head(N)
|
| 353 |
+
|
| 354 |
+
# Merge with movie information
|
| 355 |
+
recommendations = predictions_df.merge(
|
| 356 |
+
self.movies[['movie_id', 'title']],
|
| 357 |
+
on='movie_id',
|
| 358 |
+
how='left'
|
| 359 |
+
)
|
| 360 |
+
|
| 361 |
+
return recommendations[['movie_id', 'title', 'predicted_rating']]
|
| 362 |
+
|
| 363 |
+
def recommend_movies_neural(self, user_id: int, N: int = 10) -> pd.DataFrame:
|
| 364 |
+
"""
|
| 365 |
+
Generate recommendations using neural embeddings
|
| 366 |
+
|
| 367 |
+
Args:
|
| 368 |
+
user_id: ID of the user to recommend for
|
| 369 |
+
N: Number of movies to recommend
|
| 370 |
+
|
| 371 |
+
Returns:
|
| 372 |
+
DataFrame with recommended movies
|
| 373 |
+
"""
|
| 374 |
+
if user_id not in self.user_item_matrix.index:
|
| 375 |
+
return pd.DataFrame(columns=['movie_id', 'title', 'predicted_rating'])
|
| 376 |
+
|
| 377 |
+
# Get user's ratings
|
| 378 |
+
user_ratings = self.user_item_matrix.loc[user_id]
|
| 379 |
+
rated_movies = set(user_ratings[user_ratings > 0].index)
|
| 380 |
+
|
| 381 |
+
# Get all movies
|
| 382 |
+
all_movies = set(self.user_item_matrix.columns)
|
| 383 |
+
unrated_movies = all_movies - rated_movies
|
| 384 |
+
|
| 385 |
+
if not unrated_movies:
|
| 386 |
+
return pd.DataFrame(columns=['movie_id', 'title', 'predicted_rating'])
|
| 387 |
+
|
| 388 |
+
# Predict ratings for unrated movies
|
| 389 |
+
predictions = []
|
| 390 |
+
for movie_id in unrated_movies:
|
| 391 |
+
predicted_rating = self._predict_rating_neural(user_id, movie_id)
|
| 392 |
+
if predicted_rating > 0:
|
| 393 |
+
predictions.append({
|
| 394 |
+
'movie_id': movie_id,
|
| 395 |
+
'predicted_rating': predicted_rating
|
| 396 |
+
})
|
| 397 |
+
|
| 398 |
+
if not predictions:
|
| 399 |
+
return pd.DataFrame(columns=['movie_id', 'title', 'predicted_rating'])
|
| 400 |
+
|
| 401 |
+
# Sort by predicted rating and get top-N
|
| 402 |
+
predictions_df = pd.DataFrame(predictions)
|
| 403 |
+
predictions_df = predictions_df.sort_values('predicted_rating', ascending=False).head(N)
|
| 404 |
+
|
| 405 |
+
# Merge with movie information
|
| 406 |
+
recommendations = predictions_df.merge(
|
| 407 |
+
self.movies[['movie_id', 'title']],
|
| 408 |
+
on='movie_id',
|
| 409 |
+
how='left'
|
| 410 |
+
)
|
| 411 |
+
|
| 412 |
+
return recommendations[['movie_id', 'title', 'predicted_rating']]
|
| 413 |
+
|
| 414 |
+
def recommend_movies(self, user_id: int, N: int = 10, method: str = "ensemble") -> pd.DataFrame:
|
| 415 |
+
"""
|
| 416 |
+
Main recommendation function with the required signature
|
| 417 |
+
|
| 418 |
+
Args:
|
| 419 |
+
user_id: ID of the user to recommend for
|
| 420 |
+
N: Number of movies to recommend
|
| 421 |
+
method: Recommendation method ('user_based', 'item_based', 'svd', 'neural', 'ensemble')
|
| 422 |
+
|
| 423 |
+
Returns:
|
| 424 |
+
DataFrame with recommended movies
|
| 425 |
+
"""
|
| 426 |
+
if method == "user_based":
|
| 427 |
+
return self.recommend_movies_user_based(user_id, N)
|
| 428 |
+
elif method == "item_based":
|
| 429 |
+
return self.recommend_movies_item_based(user_id, N)
|
| 430 |
+
elif method == "svd":
|
| 431 |
+
return self.recommend_movies_svd(user_id, N)
|
| 432 |
+
elif method == "neural":
|
| 433 |
+
return self.recommend_movies_neural(user_id, N)
|
| 434 |
+
elif method == "ensemble":
|
| 435 |
+
return self._ensemble_recommendations(user_id, N)
|
| 436 |
+
else:
|
| 437 |
+
raise ValueError("Method must be 'user_based', 'item_based', 'svd', 'neural', or 'ensemble'")
|
| 438 |
+
|
| 439 |
+
def _ensemble_recommendations(self, user_id: int, N: int) -> pd.DataFrame:
|
| 440 |
+
"""Combine recommendations from all methods"""
|
| 441 |
+
# Get recommendations from all methods
|
| 442 |
+
user_recs = self.recommend_movies_user_based(user_id, N*2)
|
| 443 |
+
item_recs = self.recommend_movies_item_based(user_id, N*2)
|
| 444 |
+
svd_recs = self.recommend_movies_svd(user_id, N*2)
|
| 445 |
+
neural_recs = self.recommend_movies_neural(user_id, N*2)
|
| 446 |
+
|
| 447 |
+
# Combine and average scores
|
| 448 |
+
all_recs = []
|
| 449 |
+
movie_scores = {}
|
| 450 |
+
|
| 451 |
+
for recs in [user_recs, item_recs, svd_recs, neural_recs]:
|
| 452 |
+
for _, rec in recs.iterrows():
|
| 453 |
+
movie_id = rec['movie_id']
|
| 454 |
+
score = rec['predicted_rating']
|
| 455 |
+
|
| 456 |
+
if movie_id not in movie_scores:
|
| 457 |
+
movie_scores[movie_id] = []
|
| 458 |
+
movie_scores[movie_id].append(score)
|
| 459 |
+
|
| 460 |
+
# Average scores for each movie
|
| 461 |
+
for movie_id, scores in movie_scores.items():
|
| 462 |
+
avg_score = np.mean(scores)
|
| 463 |
+
all_recs.append({
|
| 464 |
+
'movie_id': movie_id,
|
| 465 |
+
'predicted_rating': avg_score
|
| 466 |
+
})
|
| 467 |
+
|
| 468 |
+
# Sort by average score and get top-N
|
| 469 |
+
all_recs_df = pd.DataFrame(all_recs)
|
| 470 |
+
all_recs_df = all_recs_df.sort_values('predicted_rating', ascending=False).head(N)
|
| 471 |
+
|
| 472 |
+
# Merge with movie information
|
| 473 |
+
recommendations = all_recs_df.merge(
|
| 474 |
+
self.movies[['movie_id', 'title']],
|
| 475 |
+
on='movie_id',
|
| 476 |
+
how='left'
|
| 477 |
+
)
|
| 478 |
+
|
| 479 |
+
return recommendations[['movie_id', 'title', 'predicted_rating']]
|
| 480 |
+
|
| 481 |
+
def _predict_rating_user_based(self, user_id: int, movie_id: int, similar_users_idx: np.ndarray) -> float:
|
| 482 |
+
"""Predict rating using user-based collaborative filtering"""
|
| 483 |
+
user_idx = list(self.user_item_matrix.index).index(user_id)
|
| 484 |
+
movie_idx = list(self.user_item_matrix.columns).index(movie_id)
|
| 485 |
+
|
| 486 |
+
numerator = 0.0
|
| 487 |
+
denominator = 0.0
|
| 488 |
+
|
| 489 |
+
for similar_user_idx in similar_users_idx:
|
| 490 |
+
similar_user_id = self.user_item_matrix.index[similar_user_idx]
|
| 491 |
+
rating = self.user_item_matrix.iloc[similar_user_idx, movie_idx]
|
| 492 |
+
|
| 493 |
+
if rating > 0:
|
| 494 |
+
similarity = self.user_similarity_matrix[user_idx, similar_user_idx]
|
| 495 |
+
user_mean = self.user_means[similar_user_id]
|
| 496 |
+
|
| 497 |
+
numerator += similarity * (rating - user_mean)
|
| 498 |
+
denominator += abs(similarity)
|
| 499 |
+
|
| 500 |
+
if denominator == 0:
|
| 501 |
+
return 0.0
|
| 502 |
+
|
| 503 |
+
user_mean = self.user_means[user_id]
|
| 504 |
+
predicted_rating = user_mean + (numerator / denominator)
|
| 505 |
+
|
| 506 |
+
return max(0.0, min(5.0, predicted_rating))
|
| 507 |
+
|
| 508 |
+
def _predict_rating_item_based(self, user_id: int, movie_id: int, top_k: int) -> float:
|
| 509 |
+
"""Predict rating using item-based collaborative filtering"""
|
| 510 |
+
user_ratings = self.user_item_matrix.loc[user_id]
|
| 511 |
+
movie_idx = list(self.user_item_matrix.columns).index(movie_id)
|
| 512 |
+
|
| 513 |
+
# Get similar items
|
| 514 |
+
similarities = self.item_similarity_matrix[movie_idx]
|
| 515 |
+
similar_items_idx = np.argsort(similarities)[::-1][1:top_k+1]
|
| 516 |
+
|
| 517 |
+
numerator = 0.0
|
| 518 |
+
denominator = 0.0
|
| 519 |
+
|
| 520 |
+
for similar_item_idx in similar_items_idx:
|
| 521 |
+
similar_movie_id = self.user_item_matrix.columns[similar_item_idx]
|
| 522 |
+
rating = user_ratings[similar_movie_id]
|
| 523 |
+
|
| 524 |
+
if rating > 0:
|
| 525 |
+
similarity = similarities[similar_item_idx]
|
| 526 |
+
item_mean = self.item_means[similar_movie_id]
|
| 527 |
+
|
| 528 |
+
numerator += similarity * (rating - item_mean)
|
| 529 |
+
denominator += abs(similarity)
|
| 530 |
+
|
| 531 |
+
if denominator == 0:
|
| 532 |
+
return 0.0
|
| 533 |
+
|
| 534 |
+
item_mean = self.item_means[movie_id]
|
| 535 |
+
predicted_rating = item_mean + (numerator / denominator)
|
| 536 |
+
|
| 537 |
+
return max(0.0, min(5.0, predicted_rating))
|
| 538 |
+
|
| 539 |
+
def _predict_rating_svd(self, user_id: int, movie_id: int) -> float:
|
| 540 |
+
"""Predict rating using SVD"""
|
| 541 |
+
user_idx = list(self.user_item_matrix.index).index(user_id)
|
| 542 |
+
movie_idx = list(self.user_item_matrix.columns).index(movie_id)
|
| 543 |
+
|
| 544 |
+
# Transform user and movie to latent space
|
| 545 |
+
user_latent = self.svd_model.transform(self.user_item_matrix.iloc[user_idx:user_idx+1])[0]
|
| 546 |
+
movie_latent = self.svd_model.components_[:, movie_idx]
|
| 547 |
+
|
| 548 |
+
# Predict rating
|
| 549 |
+
predicted_rating = np.dot(user_latent, movie_latent)
|
| 550 |
+
|
| 551 |
+
return max(0.0, min(5.0, predicted_rating))
|
| 552 |
+
|
| 553 |
+
def _predict_rating_neural(self, user_id: int, movie_id: int) -> float:
|
| 554 |
+
"""Predict rating using neural network"""
|
| 555 |
+
# Prepare input
|
| 556 |
+
X = np.array([[user_id, movie_id]])
|
| 557 |
+
X_scaled = self.scaler.transform(X)
|
| 558 |
+
|
| 559 |
+
# Predict
|
| 560 |
+
predicted_rating = self.neural_model.predict(X_scaled)[0]
|
| 561 |
+
|
| 562 |
+
return max(0.0, min(5.0, predicted_rating))
|
| 563 |
+
|
| 564 |
+
def evaluate_model(self, test_users: List[int], method: str = "ensemble", N: int = 10) -> Dict:
|
| 565 |
+
"""
|
| 566 |
+
Evaluate model performance using precision@K, recall@K, and NDCG@K
|
| 567 |
+
|
| 568 |
+
Args:
|
| 569 |
+
test_users: List of user IDs to evaluate
|
| 570 |
+
method: Recommendation method to evaluate
|
| 571 |
+
N: Number of recommendations to generate
|
| 572 |
+
|
| 573 |
+
Returns:
|
| 574 |
+
Dictionary with evaluation metrics
|
| 575 |
+
"""
|
| 576 |
+
print(f"Evaluating {method} method on {len(test_users)} users...")
|
| 577 |
+
|
| 578 |
+
precision_scores = []
|
| 579 |
+
recall_scores = []
|
| 580 |
+
ndcg_scores = []
|
| 581 |
+
|
| 582 |
+
for user_id in test_users:
|
| 583 |
+
try:
|
| 584 |
+
# Get recommendations
|
| 585 |
+
recommendations = self.recommend_movies(user_id, N=N, method=method)
|
| 586 |
+
recommended_movies = set(recommendations['movie_id'].values)
|
| 587 |
+
|
| 588 |
+
# Get actual liked movies (rating >= 4)
|
| 589 |
+
user_ratings = self.ratings[
|
| 590 |
+
(self.ratings['user_id'] == user_id) &
|
| 591 |
+
(self.ratings['rating'] >= 4)
|
| 592 |
+
]
|
| 593 |
+
liked_movies = set(user_ratings['movie_id'].values)
|
| 594 |
+
|
| 595 |
+
if len(recommended_movies) == 0:
|
| 596 |
+
precision_scores.append(0.0)
|
| 597 |
+
recall_scores.append(0.0)
|
| 598 |
+
ndcg_scores.append(0.0)
|
| 599 |
+
continue
|
| 600 |
+
|
| 601 |
+
# Calculate precision@K
|
| 602 |
+
precision = len(recommended_movies & liked_movies) / len(recommended_movies)
|
| 603 |
+
precision_scores.append(precision)
|
| 604 |
+
|
| 605 |
+
# Calculate recall@K
|
| 606 |
+
if len(liked_movies) > 0:
|
| 607 |
+
recall = len(recommended_movies & liked_movies) / len(liked_movies)
|
| 608 |
+
else:
|
| 609 |
+
recall = 0.0
|
| 610 |
+
recall_scores.append(recall)
|
| 611 |
+
|
| 612 |
+
# Calculate NDCG@K
|
| 613 |
+
ndcg = self._calculate_ndcg(list(recommendations['movie_id']), liked_movies, N)
|
| 614 |
+
ndcg_scores.append(ndcg)
|
| 615 |
+
|
| 616 |
+
except Exception as e:
|
| 617 |
+
print(f"Error evaluating user {user_id}: {str(e)}")
|
| 618 |
+
precision_scores.append(0.0)
|
| 619 |
+
recall_scores.append(0.0)
|
| 620 |
+
ndcg_scores.append(0.0)
|
| 621 |
+
|
| 622 |
+
return {
|
| 623 |
+
'precision': np.mean(precision_scores),
|
| 624 |
+
'recall': np.mean(recall_scores),
|
| 625 |
+
'ndcg': np.mean(ndcg_scores),
|
| 626 |
+
'std_precision': np.std(precision_scores),
|
| 627 |
+
'std_recall': np.std(recall_scores),
|
| 628 |
+
'std_ndcg': np.std(ndcg_scores),
|
| 629 |
+
'num_users': len(test_users)
|
| 630 |
+
}
|
| 631 |
+
|
| 632 |
+
def _calculate_ndcg(self, recommended: List[int], relevant: set, k: int = None) -> float:
|
| 633 |
+
"""Calculate Normalized Discounted Cumulative Gain"""
|
| 634 |
+
if k is None:
|
| 635 |
+
k = len(recommended)
|
| 636 |
+
|
| 637 |
+
recommended = recommended[:k]
|
| 638 |
+
|
| 639 |
+
if len(relevant) == 0:
|
| 640 |
+
return 0.0
|
| 641 |
+
|
| 642 |
+
# Calculate DCG
|
| 643 |
+
dcg = 0.0
|
| 644 |
+
for i, movie_id in enumerate(recommended):
|
| 645 |
+
if movie_id in relevant:
|
| 646 |
+
dcg += 1.0 / np.log2(i + 2)
|
| 647 |
+
|
| 648 |
+
# Calculate IDCG
|
| 649 |
+
idcg = 0.0
|
| 650 |
+
for i in range(min(len(relevant), len(recommended))):
|
| 651 |
+
idcg += 1.0 / np.log2(i + 2)
|
| 652 |
+
|
| 653 |
+
if idcg == 0:
|
| 654 |
+
return 0.0
|
| 655 |
+
|
| 656 |
+
return dcg / idcg
|
| 657 |
+
|
| 658 |
+
def train_all_models(self):
|
| 659 |
+
"""Train all recommendation models"""
|
| 660 |
+
print("Training all recommendation models...")
|
| 661 |
+
|
| 662 |
+
# Train user-based CF
|
| 663 |
+
self.train_user_based_cf()
|
| 664 |
+
|
| 665 |
+
# Train item-based CF
|
| 666 |
+
self.train_item_based_cf()
|
| 667 |
+
|
| 668 |
+
# Train SVD
|
| 669 |
+
self.train_svd(n_components=50)
|
| 670 |
+
|
| 671 |
+
# Train neural embeddings
|
| 672 |
+
self.train_neural_embeddings(hidden_layers=(100, 50), max_iter=50)
|
| 673 |
+
|
| 674 |
+
print("All models trained successfully!")
|
| 675 |
+
|
| 676 |
+
def save_model(self, filepath: str):
|
| 677 |
+
"""Save the trained model"""
|
| 678 |
+
model_data = {
|
| 679 |
+
'user_item_matrix': self.user_item_matrix,
|
| 680 |
+
'user_similarity_matrix': self.user_similarity_matrix,
|
| 681 |
+
'item_similarity_matrix': self.item_similarity_matrix,
|
| 682 |
+
'svd_model': self.svd_model,
|
| 683 |
+
'neural_model': self.neural_model,
|
| 684 |
+
'scaler': self.scaler,
|
| 685 |
+
'user_means': self.user_means,
|
| 686 |
+
'item_means': self.item_means,
|
| 687 |
+
'movies': self.movies,
|
| 688 |
+
'ratings': self.ratings
|
| 689 |
+
}
|
| 690 |
+
|
| 691 |
+
with open(filepath, 'wb') as f:
|
| 692 |
+
pickle.dump(model_data, f)
|
| 693 |
+
print(f"Model saved to {filepath}")
|
| 694 |
+
|
| 695 |
+
def load_model(self, filepath: str):
|
| 696 |
+
"""Load a trained model"""
|
| 697 |
+
with open(filepath, 'rb') as f:
|
| 698 |
+
model_data = pickle.load(f)
|
| 699 |
+
|
| 700 |
+
self.user_item_matrix = model_data['user_item_matrix']
|
| 701 |
+
self.user_similarity_matrix = model_data['user_similarity_matrix']
|
| 702 |
+
self.item_similarity_matrix = model_data['item_similarity_matrix']
|
| 703 |
+
self.svd_model = model_data['svd_model']
|
| 704 |
+
self.neural_model = model_data['neural_model']
|
| 705 |
+
self.scaler = model_data['scaler']
|
| 706 |
+
self.user_means = model_data['user_means']
|
| 707 |
+
self.item_means = model_data['item_means']
|
| 708 |
+
self.movies = model_data['movies']
|
| 709 |
+
self.ratings = model_data['ratings']
|
| 710 |
+
|
| 711 |
+
print(f"Model loaded from {filepath}")
|
| 712 |
+
|
| 713 |
+
|
| 714 |
+
def main():
|
| 715 |
+
"""Main function to demonstrate the comprehensive recommendation system"""
|
| 716 |
+
print("Comprehensive Movie Recommendation System")
|
| 717 |
+
print("=" * 50)
|
| 718 |
+
|
| 719 |
+
# Initialize the system
|
| 720 |
+
rec_system = ComprehensiveRecommendationSystem()
|
| 721 |
+
|
| 722 |
+
# Load data
|
| 723 |
+
rec_system.load_data("MovieLensDataset_small/ml-100k/u.data", "MovieLensDataset_small/ml-100k/u.item")
|
| 724 |
+
|
| 725 |
+
# Train all models
|
| 726 |
+
rec_system.train_all_models()
|
| 727 |
+
|
| 728 |
+
# Test recommendations for a specific user
|
| 729 |
+
test_user = 1
|
| 730 |
+
print(f"\nRecommendations for User {test_user}:")
|
| 731 |
+
print("-" * 40)
|
| 732 |
+
|
| 733 |
+
# Test different methods
|
| 734 |
+
methods = ["user_based", "item_based", "svd", "neural", "ensemble"]
|
| 735 |
+
|
| 736 |
+
for method in methods:
|
| 737 |
+
print(f"\n{method.upper()} Method:")
|
| 738 |
+
recommendations = rec_system.recommend_movies(test_user, N=5, method=method)
|
| 739 |
+
print(recommendations)
|
| 740 |
+
|
| 741 |
+
# Evaluate models
|
| 742 |
+
print("\nEvaluating models...")
|
| 743 |
+
print("-" * 40)
|
| 744 |
+
|
| 745 |
+
# Select a sample of users for evaluation
|
| 746 |
+
all_users = rec_system.ratings['user_id'].unique()
|
| 747 |
+
test_users = np.random.choice(all_users, min(20, len(all_users)), replace=False)
|
| 748 |
+
|
| 749 |
+
for method in methods:
|
| 750 |
+
results = rec_system.evaluate_model(test_users, method=method, N=10)
|
| 751 |
+
print(f"{method:12} | Precision: {results['precision']:.4f} | Recall: {results['recall']:.4f} | NDCG: {results['ndcg']:.4f}")
|
| 752 |
+
|
| 753 |
+
# Save model
|
| 754 |
+
rec_system.save_model("comprehensive_recommendation_model.pkl")
|
| 755 |
+
|
| 756 |
+
return rec_system
|
| 757 |
+
|
| 758 |
+
|
| 759 |
+
if __name__ == "__main__":
|
| 760 |
+
rec_system = main()
|