这篇教程手把手教你使用TensorFlow2实现RNN写得很实用,希望能帮到您。
概述RNN (Recurrent Netural Network) 是用于处理序列数据的神经网络. 所谓序列数据, 即前面的输入和后面的输入有一定的联系. 
权重共享传统神经网络:

RNN:

RNN 的权重共享和 CNN 的权重共享类似, 不同时刻共享一个权重, 大大减少了参数数量.
计算过程:
计算状态 (State)

计算输出:

案例
数据集IBIM 数据集包含了来自互联网的 50000 条关于电影的评论, 分为正面评价和负面评价.
RNN 层class RNN(tf.keras.Model): def __init__(self, units): super(RNN, self).__init__() # 初始化 [b, 64] (b 表示 batch_size) self.state0 = [tf.zeros([batch_size, units])] self.state1 = [tf.zeros([batch_size, units])] # [b, 80] => [b, 80, 100] self.embedding = tf.keras.layers.Embedding(total_words, embedding_len, input_length=max_review_len) self.rnn_cell0 = tf.keras.layers.SimpleRNNCell(units=units, dropout=0.2) self.rnn_cell1 = tf.keras.layers.SimpleRNNCell(units=units, dropout=0.2) # [b, 80, 100] => [b, 64] => [b, 1] self.out_layer = tf.keras.layers.Dense(1) def call(self, inputs, training=None): """ :param inputs: [b, 80] :param training: :return: """ state0 = self.state0 state1 = self.state1 x = self.embedding(inputs) for word in tf.unstack(x, axis=1): out0, state0 = self.rnn_cell0(word, state0, training=training) out1, state1 = self.rnn_cell1(out0, state1, training=training) # [b, 64] -> [b, 1] x = self.out_layer(out1) prob = tf.sigmoid(x) return prob
获取数据def get_data(): # 获取数据 (X_train, y_train), (X_test, y_test) = tf.keras.datasets.imdb.load_data(num_words=total_words) # 更改句子长度 X_train = tf.keras.preprocessing.sequence.pad_sequences(X_train, maxlen=max_review_len) X_test = tf.keras.preprocessing.sequence.pad_sequences(X_test, maxlen=max_review_len) # 调试输出 print(X_train.shape, y_train.shape) # (25000, 80) (25000,) print(X_test.shape, y_test.shape) # (25000, 80) (25000,) # 分割训练集 train_db = tf.data.Dataset.from_tensor_slices((X_train, y_train)) train_db = train_db.shuffle(10000).batch(batch_size, drop_remainder=True) # 分割测试集 test_db = tf.data.Dataset.from_tensor_slices((X_test, y_test)) test_db = test_db.batch(batch_size, drop_remainder=True) return train_db, test_db
完整代码import tensorflow as tfclass RNN(tf.keras.Model): def __init__(self, units): super(RNN, self).__init__() # 初始化 [b, 64] self.state0 = [tf.zeros([batch_size, units])] self.state1 = [tf.zeros([batch_size, units])] # [b, 80] => [b, 80, 100] self.embedding = tf.keras.layers.Embedding(total_words, embedding_len, input_length=max_review_len) self.rnn_cell0 = tf.keras.layers.SimpleRNNCell(units=units, dropout=0.2) self.rnn_cell1 = tf.keras.layers.SimpleRNNCell(units=units, dropout=0.2) # [b, 80, 100] => [b, 64] => [b, 1] self.out_layer = tf.keras.layers.Dense(1) def call(self, inputs, training=None): """ :param inputs: [b, 80] :param training: :return: """ state0 = self.state0 state1 = self.state1 x = self.embedding(inputs) for word in tf.unstack(x, axis=1): out0, state0 = self.rnn_cell0(word, state0, training=training) out1, state1 = self.rnn_cell1(out0, state1, training=training) # [b, 64] -> [b, 1] x = self.out_layer(out1) prob = tf.sigmoid(x) return prob# 超参数total_words = 10000 # 文字数量max_review_len = 80 # 句子长度embedding_len = 100 # 词维度batch_size = 1024 # 一次训练的样本数目learning_rate = 0.0001 # 学习率iteration_num = 20 # 迭代次数optimizer = tf.keras.optimizers.Adam(learning_rate=learning_rate) # 优化器loss = tf.losses.BinaryCrossentropy(from_logits=True) # 损失model = RNN(64)# 调试输出summarymodel.build(input_shape=[None, 64])print(model.summary())# 组合model.compile(optimizer=optimizer, loss=loss, metrics=["accuracy"])def get_data(): # 获取数据 (X_train, y_train), (X_test, y_test) = tf.keras.datasets.imdb.load_data(num_words=total_words) # 更改句子长度 X_train = tf.keras.preprocessing.sequence.pad_sequences(X_train, maxlen=max_review_len) X_test = tf.keras.preprocessing.sequence.pad_sequences(X_test, maxlen=max_review_len) # 调试输出 print(X_train.shape, y_train.shape) # (25000, 80) (25000,) print(X_test.shape, y_test.shape) # (25000, 80) (25000,) # 分割训练集 train_db = tf.data.Dataset.from_tensor_slices((X_train, y_train)) train_db = train_db.shuffle(10000).batch(batch_size, drop_remainder=True) # 分割测试集 test_db = tf.data.Dataset.from_tensor_slices((X_test, y_test)) test_db = test_db.batch(batch_size, drop_remainder=True) return train_db, test_dbif __name__ == "__main__": # 获取分割的数据集 train_db, test_db = get_data() # 拟合 model.fit(train_db, epochs=iteration_num, validation_data=test_db, validation_freq=1) 输出结果: Model: "rnn" _________________________________________________________________ Layer (type) Output Shape Param # ================================================================= embedding (Embedding) multiple 1000000 _________________________________________________________________ simple_rnn_cell (SimpleRNNCe multiple 10560 _________________________________________________________________ simple_rnn_cell_1 (SimpleRNN multiple 8256 _________________________________________________________________ dense (Dense) multiple 65 ================================================================= Total params: 1,018,881 Trainable params: 1,018,881 Non-trainable params: 0 _________________________________________________________________ None (25000, 80) (25000,) (25000, 80) (25000,) Epoch 1/20 2021-07-10 17:59:45.150639: I tensorflow/compiler/mlir/mlir_graph_optimization_pass.cc:176] None of the MLIR Optimization Passes are enabled (registered 2) 24/24 [==============================] - 12s 294ms/step - loss: 0.7113 - accuracy: 0.5033 - val_loss: 0.6968 - val_accuracy: 0.4994 Epoch 2/20 24/24 [==============================] - 7s 292ms/step - loss: 0.6951 - accuracy: 0.5005 - val_loss: 0.6939 - val_accuracy: 0.4994 Epoch 3/20 24/24 [==============================] - 7s 297ms/step - loss: 0.6937 - accuracy: 0.5000 - val_loss: 0.6935 - val_accuracy: 0.4994 Epoch 4/20 24/24 [==============================] - 8s 316ms/step - loss: 0.6934 - accuracy: 0.5001 - val_loss: 0.6933 - val_accuracy: 0.4994 Epoch 5/20 24/24 [==============================] - 7s 301ms/step - loss: 0.6934 - accuracy: 0.4996 - val_loss: 0.6933 - val_accuracy: 0.4994 Epoch 6/20 24/24 [==============================] - 8s 334ms/step - loss: 0.6932 - accuracy: 0.5000 - val_loss: 0.6932 - val_accuracy: 0.4994 Epoch 7/20 24/24 [==============================] - 10s 398ms/step - loss: 0.6931 - accuracy: 0.5006 - val_loss: 0.6932 - val_accuracy: 0.4994 Epoch 8/20 24/24 [==============================] - 9s 382ms/step - loss: 0.6930 - accuracy: 0.5006 - val_loss: 0.6931 - val_accuracy: 0.4994 Epoch 9/20 24/24 [==============================] - 8s 322ms/step - loss: 0.6924 - accuracy: 0.4995 - val_loss: 0.6913 - val_accuracy: 0.5240 Epoch 10/20 24/24 [==============================] - 8s 321ms/step - loss: 0.6812 - accuracy: 0.5501 - val_loss: 0.6655 - val_accuracy: 0.5767 Epoch 11/20 24/24 [==============================] - 8s 318ms/step - loss: 0.6381 - accuracy: 0.6896 - val_loss: 0.6235 - val_accuracy: 0.7399 Epoch 12/20 24/24 [==============================] - 8s 323ms/step - loss: 0.6088 - accuracy: 0.7655 - val_loss: 0.6110 - val_accuracy: 0.7533 Epoch 13/20 24/24 [==============================] - 8s 321ms/step - loss: 0.5949 - accuracy: 0.7956 - val_loss: 0.6111 - val_accuracy: 0.7878 Epoch 14/20 24/24 [==============================] - 8s 324ms/step - loss: 0.5859 - accuracy: 0.8142 - val_loss: 0.5993 - val_accuracy: 0.7904 Epoch 15/20 24/24 [==============================] - 8s 330ms/step - loss: 0.5791 - accuracy: 0.8318 - val_loss: 0.5961 - val_accuracy: 0.7907 Epoch 16/20 24/24 [==============================] - 8s 340ms/step - loss: 0.5739 - accuracy: 0.8421 - val_loss: 0.5942 - val_accuracy: 0.7961 Epoch 17/20 24/24 [==============================] - 9s 378ms/step - loss: 0.5701 - accuracy: 0.8497 - val_loss: 0.5933 - val_accuracy: 0.8014 Epoch 18/20 24/24 [==============================] - 9s 361ms/step - loss: 0.5665 - accuracy: 0.8589 - val_loss: 0.5958 - val_accuracy: 0.8082 Epoch 19/20 24/24 [==============================] - 8s 353ms/step - loss: 0.5630 - accuracy: 0.8681 - val_loss: 0.5931 - val_accuracy: 0.7966 Epoch 20/20 24/24 [==============================] - 8s 314ms/step - loss: 0.5614 - accuracy: 0.8702 - val_loss: 0.5925 - val_accuracy: 0.7959 Process finished with exit code 0
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