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HenryAI
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KerasBERTv1-Data

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# Add random noise to the labels - important trick!
labels += 0.05 * tf.random.uniform(tf.shape(labels))
# Train the discriminator
with tf.GradientTape() as tape:
predictions = self.discriminator(combined_images)
d_loss = self.loss_fn(labels, predictions)
grads = tape.gradient(d_loss, self.discriminator.trainable_weights)
self.d_optimizer.apply_gradients(
zip(grads, self.discriminator.trainable_weights)
)
# Sample random points in the latent space
random_latent_vectors = tf.random.normal(shape=(batch_size, self.latent_dim))
# Assemble labels that say "all real images"
misleading_labels = tf.zeros((batch_size, 1))
# Train the generator (note that we should *not* update the weights
# of the discriminator)!
with tf.GradientTape() as tape:
predictions = self.discriminator(self.generator(random_latent_vectors))
g_loss = self.loss_fn(misleading_labels, predictions)
grads = tape.gradient(g_loss, self.generator.trainable_weights)
self.g_optimizer.apply_gradients(zip(grads, self.generator.trainable_weights))
return {"d_loss": d_loss, "g_loss": g_loss}
Let's test-drive it:
# Prepare the dataset. We use both the training & test MNIST digits.
batch_size = 64
(x_train, _), (x_test, _) = keras.datasets.mnist.load_data()
all_digits = np.concatenate([x_train, x_test])
all_digits = all_digits.astype("float32") / 255.0
all_digits = np.reshape(all_digits, (-1, 28, 28, 1))
dataset = tf.data.Dataset.from_tensor_slices(all_digits)
dataset = dataset.shuffle(buffer_size=1024).batch(batch_size)
gan = GAN(discriminator=discriminator, generator=generator, latent_dim=latent_dim)
gan.compile(
d_optimizer=keras.optimizers.Adam(learning_rate=0.0003),
g_optimizer=keras.optimizers.Adam(learning_rate=0.0003),
loss_fn=keras.losses.BinaryCrossentropy(from_logits=True),
)
# To limit the execution time, we only train on 100 batches. You can train on
# the entire dataset. You will need about 20 epochs to get nice results.
gan.fit(dataset.take(100), epochs=1)
100/100 [==============================] - 60s 591ms/step - d_loss: 0.4534 - g_loss: 0.9839
<tensorflow.python.keras.callbacks.History at 0x151e64290>
The ideas behind deep learning are simple, so why should their implementation be painful?Understanding masking & padding
Authors: Scott Zhu, Francois Chollet
Date created: 2019/07/16
Last modified: 2020/04/14
Description: Complete guide to using mask-aware sequence layers in Keras.
View in Colab • GitHub source
Setup
import numpy as np
import tensorflow as tf
from tensorflow import keras
from tensorflow.keras import layers
Introduction
Masking is a way to tell sequence-processing layers that certain timesteps in an input are missing, and thus should be skipped when processing the data.
Padding is a special form of masking where the masked steps are at the start or the end of a sequence. Padding comes from the need to encode sequence data into contiguous batches: in order to make all sequences in a batch fit a given standard length, it is necessary to pad or truncate some sequences.
Let's take a close look.
Padding sequence data
When processing sequence data, it is very common for individual samples to have different lengths. Consider the following example (text tokenized as words):
[
["Hello", "world", "!"],
["How", "are", "you", "doing", "today"],
["The", "weather", "will", "be", "nice", "tomorrow"],
]
After vocabulary lookup, the data might be vectorized as integers, e.g.:
[
[71, 1331, 4231]
[73, 8, 3215, 55, 927],
[83, 91, 1, 645, 1253, 927],
]
The data is a nested list where individual samples have length 3, 5, and 6, respectively. Since the input data for a deep learning model must be a single tensor (of shape e.g. (batch_size, 6, vocab_size) in this case), samples that are shorter than the longest item need to be padded with some placeholder value (alternatively, one might also truncate long samples before padding short samples).
Keras provides a utility function to truncate and pad Python lists to a common length: tf.keras.preprocessing.sequence.pad_sequences.
raw_inputs = [
[711, 632, 71],
[73, 8, 3215, 55, 927],
[83, 91, 1, 645, 1253, 927],
]
# By default, this will pad using 0s; it is configurable via the
# "value" parameter.
# Note that you could "pre" padding (at the beginning) or
# "post" padding (at the end).