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111 lines
4.5 KiB
Markdown
111 lines
4.5 KiB
Markdown
# Use Spark DataFrames for Deep Learning
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---
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[Run in Google Colab](https://colab.research.google.com/github/intel-analytics/BigDL/blob/branch-2.0/python/orca/colab-notebook/quickstart/ncf_dataframe.ipynb) [View source on GitHub](https://github.com/intel-analytics/BigDL/blob/branch-2.0/python/orca/colab-notebook/quickstart/ncf_dataframe.ipynb)
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---
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**In this guide we will describe how to use Apache Spark Dataframes to scale-out data processing for distributed deep learning.**
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The dataset used in this guide is [movielens-1M](https://grouplens.org/datasets/movielens/1m/), which contains 1 million ratings of 5 levels from 6000 users on 4000 movies. We will read the data into Spark Dataframe and directly use the Spark Dataframe as the input to the distributed training.
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### 1. Read input data into Spark DataFrame
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First, read the input data into Spark Dataframes.
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```python
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from bigdl.orca import OrcaContext
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spark = OrcaContext.get_spark_session()
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# read csv with specifying column names
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df = spark.read.csv(new_rating_files, sep=':', inferSchema=True).toDF(
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"user", "item", "label", "timestamp")
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```
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### 2. Process data using Spark Dataframe
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Next, process the data using Spark Dataframe operations.
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```python
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# update label starting from 0. That's because ratings go from 1 to 5, while the matrix column index goes from 0 to 4
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df = df.withColumn('label', df.label-1)
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# split to train/test dataset
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train_data, test_data = df.randomSplit([0.8, 0.2], 100)
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```
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### 3. Define NCF model
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This example defines NCF model in the _Creator Function_ using TensroFlow 2 APIs as follows.
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```python
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from tensorflow import keras
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import tensorflow as tf
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def model_creator(config):
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embedding_size=16
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user = keras.layers.Input(dtype=tf.int32, shape=(None,))
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item = keras.layers.Input(dtype=tf.int32, shape=(None,))
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label = keras.layers.Input(dtype=tf.int32, shape=(None,))
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with tf.name_scope("GMF"):
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user_embed_GMF = keras.layers.Embedding(max_user_id + 1, embedding_size)(user)
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item_embed_GMF = keras.layers.Embedding(max_item_id + 1, embedding_size)(item)
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GMF = keras.layers.Multiply()([user_embed_GMF, item_embed_GMF])
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with tf.name_scope("MLP"):
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user_embed_MLP = keras.layers.Embedding(max_user_id + 1, embedding_size)(user)
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item_embed_MLP = keras.layers.Embedding(max_item_id + 1, embedding_size)(item)
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interaction = concat([user_embed_MLP, item_embed_MLP], axis=-1)
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layer1_MLP = keras.layers.Dense(units=embedding_size * 2, activation='relu')(interaction)
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layer1_MLP = keras.layers.Dropout(rate=0.2)(layer1_MLP)
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layer2_MLP = keras.layers.Dense(units=embedding_size, activation='relu')(layer1_MLP)
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layer2_MLP = keras.layers.Dropout(rate=0.2)(layer2_MLP)
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layer3_MLP = keras.layers.Dense(units=embedding_size // 2, activation='relu')(layer2_MLP)
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layer3_MLP = keras.layers.Dropout(rate=0.2)(layer3_MLP)
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# Concate the two parts together
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with tf.name_scope("concatenation"):
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concatenation = tf.concat([GMF, layer3_MLP], axis=-1)
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outputs = keras.layers.Dense(units=5, activation='softmax')(concatenation)
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model = keras.Model(inputs=[user, item], outputs=outputs)
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model.compile(optimizer="adam",
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loss="sparse_categorical_crossentropy",
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metrics=['accuracy'])
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return model
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```
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### 4. Fit with Orca Estimator
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Finally, run distributed model training/inference on the Spark Dataframes directly.
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```python
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from bigdl.orca.learn.tf2 import Estimator
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# create an Estimator
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est = Estimator.from_keras(model_creator=model_creator) # the model accept two inputs and one label
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# fit with Estimator
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stats = est.fit(train_data,
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epochs=epochs,
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batch_size=batch_size,
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feature_cols=['user', 'item'], # specifies which column(s) to be used as inputs
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label_cols=['label'], # specifies which column(s) to be used as labels
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steps_per_epoch=800000 // batch_size,
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validation_data=test_data,
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validation_steps=200000 // batch_size)
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checkpoint_path = os.path.join(model_dir, "NCF.ckpt")
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est.save(checkpoint_path)
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# evaluate with Estimator
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stats = est.evaluate(test_data,
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feature_cols=['user', 'item'], # specifies which column(s) to be used as inputs
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label_cols=['label'], # specifies which column(s) to be used as labels
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num_steps=100000 // batch_size)
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est.shutdown()
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print(stats)
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```
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