סרטים מומלצים: אחזור עם אסטרטגיית הפצה

במדריך זה, אנחנו הולכים להתאמן באותו המודל יחזור כפי שעשינו תחזור בסיס ההדרכה, אבל עם אסטרטגיית הפצה.

אנחנו הולכים ל:

1. קבל את הנתונים שלנו ופצל אותם לסט הדרכה ומבחנים.
2. הגדר שני GPUs וירטואליים ו- TensorFlow MirroredStrategy.
3. הטמע מודל אחזור באמצעות MirroredStrategy.
4. התאם אותו עם MirrorredStrategy והעריך אותו.

יבוא

קודם כל נסלק את היבוא שלנו מהדרך.

pip install -q tensorflow-recommenders
pip install -q --upgrade tensorflow-datasets

import os
import pprint
import tempfile

from typing import Dict, Text

import numpy as np
import tensorflow as tf
import tensorflow_datasets as tfds

import tensorflow_recommenders as tfrs

הכנת מערך הנתונים

אנחנו מכינים את הנתונים בדיוק באותו אופן כפי שאנו עושים אחזור בסיסי הדרכה.

# Ratings data.
ratings = tfds.load("movielens/100k-ratings", split="train")
# Features of all the available movies.
movies = tfds.load("movielens/100k-movies", split="train")

for x in ratings.take(1).as_numpy_iterator():
  pprint.pprint(x)

for x in movies.take(1).as_numpy_iterator():
  pprint.pprint(x)

ratings = ratings.map(lambda x: {
    "movie_title": x["movie_title"],
    "user_id": x["user_id"],
})
movies = movies.map(lambda x: x["movie_title"])

tf.random.set_seed(42)
shuffled = ratings.shuffle(100_000, seed=42, reshuffle_each_iteration=False)

train = shuffled.take(80_000)
test = shuffled.skip(80_000).take(20_000)

movie_titles = movies.batch(1_000)
user_ids = ratings.batch(1_000_000).map(lambda x: x["user_id"])

unique_movie_titles = np.unique(np.concatenate(list(movie_titles)))
unique_user_ids = np.unique(np.concatenate(list(user_ids)))

unique_movie_titles[:10]

{'bucketized_user_age': 45.0,
 'movie_genres': array([7]),
 'movie_id': b'357',
 'movie_title': b"One Flew Over the Cuckoo's Nest (1975)",
 'raw_user_age': 46.0,
 'timestamp': 879024327,
 'user_gender': True,
 'user_id': b'138',
 'user_occupation_label': 4,
 'user_occupation_text': b'doctor',
 'user_rating': 4.0,
 'user_zip_code': b'53211'}
2021-10-14 11:16:44.748468: W tensorflow/core/kernels/data/cache_dataset_ops.cc:768] The calling iterator did not fully read the dataset being cached. In order to avoid unexpected truncation of the dataset, the partially cached contents of the dataset  will be discarded. This can happen if you have an input pipeline similar to `dataset.cache().take(k).repeat()`. You should use `dataset.take(k).cache().repeat()` instead.
{'movie_genres': array([4]),
 'movie_id': b'1681',
 'movie_title': b'You So Crazy (1994)'}
2021-10-14 11:16:45.396856: W tensorflow/core/kernels/data/cache_dataset_ops.cc:768] The calling iterator did not fully read the dataset being cached. In order to avoid unexpected truncation of the dataset, the partially cached contents of the dataset  will be discarded. This can happen if you have an input pipeline similar to `dataset.cache().take(k).repeat()`. You should use `dataset.take(k).cache().repeat()` instead.
array([b"'Til There Was You (1997)", b'1-900 (1994)',
       b'101 Dalmatians (1996)', b'12 Angry Men (1957)', b'187 (1997)',
       b'2 Days in the Valley (1996)',
       b'20,000 Leagues Under the Sea (1954)',
       b'2001: A Space Odyssey (1968)',
       b'3 Ninjas: High Noon At Mega Mountain (1998)',
       b'39 Steps, The (1935)'], dtype=object)

הגדר שני GPUs וירטואליים

אם לא הוספת מאיצי GPU ל-Colab שלך, אנא נתק את זמן הריצה של Colab ועשה זאת כעת. אנחנו צריכים את ה-GPU כדי להפעיל את הקוד שלהלן:

gpus = tf.config.list_physical_devices("GPU")
if gpus:
  # Create 2 virtual GPUs with 1GB memory each
  try:
    tf.config.set_logical_device_configuration(
        gpus[0],
        [tf.config.LogicalDeviceConfiguration(memory_limit=1024),
         tf.config.LogicalDeviceConfiguration(memory_limit=1024)])
    logical_gpus = tf.config.list_logical_devices("GPU")
    print(len(gpus), "Physical GPU,", len(logical_gpus), "Logical GPUs")
  except RuntimeError as e:
    # Virtual devices must be set before GPUs have been initialized
    print(e)

strategy = tf.distribute.MirroredStrategy()

Virtual devices cannot be modified after being initialized
INFO:tensorflow:Using MirroredStrategy with devices ('/job:localhost/replica:0/task:0/device:GPU:0',)
INFO:tensorflow:Using MirroredStrategy with devices ('/job:localhost/replica:0/task:0/device:GPU:0',)

יישום מודל

אנו ליישם את user_model, movie_model, מדדה משימה באותו אופן כפי שאנו עושים נחזור בסיס ההדרכה, אבל אנחנו עוטפים אותם היקף אסטרטגיית הפצה:

embedding_dimension = 32

with strategy.scope():
  user_model = tf.keras.Sequential([
    tf.keras.layers.StringLookup(
        vocabulary=unique_user_ids, mask_token=None),
    # We add an additional embedding to account for unknown tokens.
    tf.keras.layers.Embedding(len(unique_user_ids) + 1, embedding_dimension)
  ])

  movie_model = tf.keras.Sequential([
    tf.keras.layers.StringLookup(
        vocabulary=unique_movie_titles, mask_token=None),
    tf.keras.layers.Embedding(len(unique_movie_titles) + 1, embedding_dimension)
  ])

  metrics = tfrs.metrics.FactorizedTopK(
    candidates=movies.batch(128).map(movie_model)
  )

  task = tfrs.tasks.Retrieval(
    metrics=metrics
  )

INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).
INFO:tensorflow:Reduce to /job:localhost/replica:0/task:0/device:CPU:0 then broadcast to ('/job:localhost/replica:0/task:0/device:CPU:0',).

כעת נוכל לחבר את הכל יחד למודל. זה בדיוק אותו הדבר כמו תחזור בסיס ההדרכה.

class MovielensModel(tfrs.Model):

  def __init__(self, user_model, movie_model):
    super().__init__()
    self.movie_model: tf.keras.Model = movie_model
    self.user_model: tf.keras.Model = user_model
    self.task: tf.keras.layers.Layer = task

  def compute_loss(self, features: Dict[Text, tf.Tensor], training=False) -> tf.Tensor:
    # We pick out the user features and pass them into the user model.
    user_embeddings = self.user_model(features["user_id"])
    # And pick out the movie features and pass them into the movie model,
    # getting embeddings back.
    positive_movie_embeddings = self.movie_model(features["movie_title"])

    # The task computes the loss and the metrics.
    return self.task(user_embeddings, positive_movie_embeddings)

התאמה והערכה

כעת אנו מייצרים ומרכיבים את המודל במסגרת אסטרטגיית ההפצה.

שים לב כי אנו משתמשים האופטימיזציה אדם כאן במקום Adagrad כמו תחזור בסיס ההדרכה מאז Adagrad אינו נתמך כאן.

with strategy.scope():
  model = MovielensModel(user_model, movie_model)
  model.compile(optimizer=tf.keras.optimizers.Adam(learning_rate=0.1))

לאחר מכן ערבב, אצווה ושמור את נתוני ההדרכה וההערכה.

cached_train = train.shuffle(100_000).batch(8192).cache()
cached_test = test.batch(4096).cache()

לאחר מכן אמן את הדגם:

model.fit(cached_train, epochs=3)

2021-10-14 11:16:50.692190: W tensorflow/core/grappler/optimizers/data/auto_shard.cc:461] The `assert_cardinality` transformation is currently not handled by the auto-shard rewrite and will be removed.
Epoch 1/3
10/10 [==============================] - 8s 328ms/step - factorized_top_k/top_1_categorical_accuracy: 5.0000e-05 - factorized_top_k/top_5_categorical_accuracy: 8.2500e-04 - factorized_top_k/top_10_categorical_accuracy: 0.0025 - factorized_top_k/top_50_categorical_accuracy: 0.0220 - factorized_top_k/top_100_categorical_accuracy: 0.0537 - loss: 70189.8047 - regularization_loss: 0.0000e+00 - total_loss: 70189.8047
Epoch 2/3
10/10 [==============================] - 3s 329ms/step - factorized_top_k/top_1_categorical_accuracy: 3.3750e-04 - factorized_top_k/top_5_categorical_accuracy: 0.0113 - factorized_top_k/top_10_categorical_accuracy: 0.0251 - factorized_top_k/top_50_categorical_accuracy: 0.1268 - factorized_top_k/top_100_categorical_accuracy: 0.2325 - loss: 66736.4560 - regularization_loss: 0.0000e+00 - total_loss: 66736.4560
Epoch 3/3
10/10 [==============================] - 3s 332ms/step - factorized_top_k/top_1_categorical_accuracy: 0.0012 - factorized_top_k/top_5_categorical_accuracy: 0.0198 - factorized_top_k/top_10_categorical_accuracy: 0.0417 - factorized_top_k/top_50_categorical_accuracy: 0.1834 - factorized_top_k/top_100_categorical_accuracy: 0.3138 - loss: 64871.2997 - regularization_loss: 0.0000e+00 - total_loss: 64871.2997
<keras.callbacks.History at 0x7fb74c479190>

אתה יכול לראות מיומן ההדרכה ש-TFRS עושה שימוש בשני ה-GPUs הוירטואליים.

לבסוף, נוכל להעריך את המודל שלנו במערך הבדיקות:

model.evaluate(cached_test, return_dict=True)

2021-10-14 11:17:05.371963: W tensorflow/core/grappler/optimizers/data/auto_shard.cc:461] The `assert_cardinality` transformation is currently not handled by the auto-shard rewrite and will be removed.
5/5 [==============================] - 4s 193ms/step - factorized_top_k/top_1_categorical_accuracy: 5.0000e-05 - factorized_top_k/top_5_categorical_accuracy: 0.0013 - factorized_top_k/top_10_categorical_accuracy: 0.0043 - factorized_top_k/top_50_categorical_accuracy: 0.0639 - factorized_top_k/top_100_categorical_accuracy: 0.1531 - loss: 32404.8092 - regularization_loss: 0.0000e+00 - total_loss: 32404.8092
{'factorized_top_k/top_1_categorical_accuracy': 4.999999873689376e-05,
 'factorized_top_k/top_5_categorical_accuracy': 0.0013000000035390258,
 'factorized_top_k/top_10_categorical_accuracy': 0.00430000014603138,
 'factorized_top_k/top_50_categorical_accuracy': 0.06385000050067902,
 'factorized_top_k/top_100_categorical_accuracy': 0.1530500054359436,
 'loss': 29363.98046875,
 'regularization_loss': 0,
 'total_loss': 29363.98046875}

זה מסיים את האחזור עם הדרכה של אסטרטגיית הפצה.