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fchollet--deep-learning-wit…/chapter07_deep-dive-keras.ipynb
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{
"cells": [
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"This is a companion notebook for the book [Deep Learning with Python, Third Edition](https://www.manning.com/books/deep-learning-with-python-third-edition). For readability, it only contains runnable code blocks and section titles, and omits everything else in the book: text paragraphs, figures, and pseudocode.\n\n**If you want to be able to follow what's going on, I recommend reading the notebook side by side with your copy of the book.**\n\nThe book's contents are available online at [deeplearningwithpython.io](https://deeplearningwithpython.io)."
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"!pip install keras keras-hub --upgrade -q"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"import os\n",
"os.environ[\"KERAS_BACKEND\"] = \"jax\""
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"cellView": "form",
"colab_type": "code"
},
"outputs": [],
"source": [
"# @title\n",
"import os\n",
"from IPython.core.magic import register_cell_magic\n",
"\n",
"@register_cell_magic\n",
"def backend(line, cell):\n",
" current, required = os.environ.get(\"KERAS_BACKEND\", \"\"), line.split()[-1]\n",
" if current == required:\n",
" get_ipython().run_cell(cell)\n",
" else:\n",
" print(\n",
" f\"This cell requires the {required} backend. To run it, change KERAS_BACKEND to \"\n",
" f\"\\\"{required}\\\" at the top of the notebook, restart the runtime, and rerun the notebook.\"\n",
" )"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"## A deep dive on Keras"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"### A spectrum of workflows"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"### Different ways to build Keras models"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"#### The Sequential model"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"import keras\n",
"from keras import layers\n",
"\n",
"model = keras.Sequential(\n",
" [\n",
" layers.Dense(64, activation=\"relu\"),\n",
" layers.Dense(10, activation=\"softmax\"),\n",
" ]\n",
")"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model = keras.Sequential()\n",
"model.add(layers.Dense(64, activation=\"relu\"))\n",
"model.add(layers.Dense(10, activation=\"softmax\"))"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model.weights"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model.build(input_shape=(None, 3))\n",
"model.weights"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model.summary(line_length=80)"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model = keras.Sequential(name=\"my_example_model\")\n",
"model.add(layers.Dense(64, activation=\"relu\", name=\"my_first_layer\"))\n",
"model.add(layers.Dense(10, activation=\"softmax\", name=\"my_last_layer\"))\n",
"model.build((None, 3))\n",
"model.summary(line_length=80)"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model = keras.Sequential()\n",
"model.add(keras.Input(shape=(3,)))\n",
"model.add(layers.Dense(64, activation=\"relu\"))"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model.summary(line_length=80)"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model.add(layers.Dense(10, activation=\"softmax\"))\n",
"model.summary(line_length=80)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"#### The Functional API"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### A simple example"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"inputs = keras.Input(shape=(3,), name=\"my_input\")\n",
"features = layers.Dense(64, activation=\"relu\")(inputs)\n",
"outputs = layers.Dense(10, activation=\"softmax\")(features)\n",
"model = keras.Model(inputs=inputs, outputs=outputs, name=\"my_functional_model\")"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"inputs = keras.Input(shape=(3,), name=\"my_input\")"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"inputs.shape"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"inputs.dtype"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"features = layers.Dense(64, activation=\"relu\")(inputs)"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"features.shape"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"outputs = layers.Dense(10, activation=\"softmax\")(features)\n",
"model = keras.Model(inputs=inputs, outputs=outputs, name=\"my_functional_model\")"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model.summary(line_length=80)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### Multi-input, multi-output models"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"vocabulary_size = 10000\n",
"num_tags = 100\n",
"num_departments = 4\n",
"\n",
"title = keras.Input(shape=(vocabulary_size,), name=\"title\")\n",
"text_body = keras.Input(shape=(vocabulary_size,), name=\"text_body\")\n",
"tags = keras.Input(shape=(num_tags,), name=\"tags\")\n",
"\n",
"features = layers.Concatenate()([title, text_body, tags])\n",
"features = layers.Dense(64, activation=\"relu\", name=\"dense_features\")(features)\n",
"\n",
"priority = layers.Dense(1, activation=\"sigmoid\", name=\"priority\")(features)\n",
"department = layers.Dense(\n",
" num_departments, activation=\"softmax\", name=\"department\"\n",
")(features)\n",
"\n",
"model = keras.Model(\n",
" inputs=[title, text_body, tags],\n",
" outputs=[priority, department],\n",
")"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### Training a multi-input, multi-output model"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"import numpy as np\n",
"\n",
"num_samples = 1280\n",
"\n",
"title_data = np.random.randint(0, 2, size=(num_samples, vocabulary_size))\n",
"text_body_data = np.random.randint(0, 2, size=(num_samples, vocabulary_size))\n",
"tags_data = np.random.randint(0, 2, size=(num_samples, num_tags))\n",
"\n",
"priority_data = np.random.random(size=(num_samples, 1))\n",
"department_data = np.random.randint(0, num_departments, size=(num_samples, 1))\n",
"\n",
"model.compile(\n",
" optimizer=\"adam\",\n",
" loss=[\"mean_squared_error\", \"sparse_categorical_crossentropy\"],\n",
" metrics=[[\"mean_absolute_error\"], [\"accuracy\"]],\n",
")\n",
"model.fit(\n",
" [title_data, text_body_data, tags_data],\n",
" [priority_data, department_data],\n",
" epochs=1,\n",
")\n",
"model.evaluate(\n",
" [title_data, text_body_data, tags_data], [priority_data, department_data]\n",
")\n",
"priority_preds, department_preds = model.predict(\n",
" [title_data, text_body_data, tags_data]\n",
")"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model.compile(\n",
" optimizer=\"adam\",\n",
" loss={\n",
" \"priority\": \"mean_squared_error\",\n",
" \"department\": \"sparse_categorical_crossentropy\",\n",
" },\n",
" metrics={\n",
" \"priority\": [\"mean_absolute_error\"],\n",
" \"department\": [\"accuracy\"],\n",
" },\n",
")\n",
"model.fit(\n",
" {\"title\": title_data, \"text_body\": text_body_data, \"tags\": tags_data},\n",
" {\"priority\": priority_data, \"department\": department_data},\n",
" epochs=1,\n",
")\n",
"model.evaluate(\n",
" {\"title\": title_data, \"text_body\": text_body_data, \"tags\": tags_data},\n",
" {\"priority\": priority_data, \"department\": department_data},\n",
")\n",
"priority_preds, department_preds = model.predict(\n",
" {\"title\": title_data, \"text_body\": text_body_data, \"tags\": tags_data}\n",
")"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### The power of the Functional API: Access to layer connectivity"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"###### Plotting layer connectivity"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"keras.utils.plot_model(model, \"ticket_classifier.png\")"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"keras.utils.plot_model(\n",
" model,\n",
" \"ticket_classifier_with_shape_info.png\",\n",
" show_shapes=True,\n",
" show_layer_names=True,\n",
")"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"###### Feature extraction with a Functional model"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model.layers"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model.layers[3].input"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model.layers[3].output"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"features = model.layers[4].output\n",
"difficulty = layers.Dense(3, activation=\"softmax\", name=\"difficulty\")(features)\n",
"\n",
"new_model = keras.Model(\n",
" inputs=[title, text_body, tags], outputs=[priority, department, difficulty]\n",
")"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"keras.utils.plot_model(\n",
" new_model,\n",
" \"updated_ticket_classifier.png\",\n",
" show_shapes=True,\n",
" show_layer_names=True,\n",
")"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"#### Subclassing the Model class"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### Rewriting our previous example as a subclassed model"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"class CustomerTicketModel(keras.Model):\n",
" def __init__(self, num_departments):\n",
" super().__init__()\n",
" self.concat_layer = layers.Concatenate()\n",
" self.mixing_layer = layers.Dense(64, activation=\"relu\")\n",
" self.priority_scorer = layers.Dense(1, activation=\"sigmoid\")\n",
" self.department_classifier = layers.Dense(\n",
" num_departments, activation=\"softmax\"\n",
" )\n",
"\n",
" def call(self, inputs):\n",
" title = inputs[\"title\"]\n",
" text_body = inputs[\"text_body\"]\n",
" tags = inputs[\"tags\"]\n",
"\n",
" features = self.concat_layer([title, text_body, tags])\n",
" features = self.mixing_layer(features)\n",
" priority = self.priority_scorer(features)\n",
" department = self.department_classifier(features)\n",
" return priority, department"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model = CustomerTicketModel(num_departments=4)\n",
"\n",
"priority, department = model(\n",
" {\"title\": title_data, \"text_body\": text_body_data, \"tags\": tags_data}\n",
")"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model.compile(\n",
" optimizer=\"adam\",\n",
" loss=[\"mean_squared_error\", \"sparse_categorical_crossentropy\"],\n",
" metrics=[[\"mean_absolute_error\"], [\"accuracy\"]],\n",
")\n",
"model.fit(\n",
" {\"title\": title_data, \"text_body\": text_body_data, \"tags\": tags_data},\n",
" [priority_data, department_data],\n",
" epochs=1,\n",
")\n",
"model.evaluate(\n",
" {\"title\": title_data, \"text_body\": text_body_data, \"tags\": tags_data},\n",
" [priority_data, department_data],\n",
")\n",
"priority_preds, department_preds = model.predict(\n",
" {\"title\": title_data, \"text_body\": text_body_data, \"tags\": tags_data}\n",
")"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### Beware: What subclassed models don't support"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"#### Mixing and matching different components"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"class Classifier(keras.Model):\n",
" def __init__(self, num_classes=2):\n",
" super().__init__()\n",
" if num_classes == 2:\n",
" num_units = 1\n",
" activation = \"sigmoid\"\n",
" else:\n",
" num_units = num_classes\n",
" activation = \"softmax\"\n",
" self.dense = layers.Dense(num_units, activation=activation)\n",
"\n",
" def call(self, inputs):\n",
" return self.dense(inputs)\n",
"\n",
"inputs = keras.Input(shape=(3,))\n",
"features = layers.Dense(64, activation=\"relu\")(inputs)\n",
"outputs = Classifier(num_classes=10)(features)\n",
"model = keras.Model(inputs=inputs, outputs=outputs)"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"inputs = keras.Input(shape=(64,))\n",
"outputs = layers.Dense(1, activation=\"sigmoid\")(inputs)\n",
"binary_classifier = keras.Model(inputs=inputs, outputs=outputs)\n",
"\n",
"class MyModel(keras.Model):\n",
" def __init__(self, num_classes=2):\n",
" super().__init__()\n",
" self.dense = layers.Dense(64, activation=\"relu\")\n",
" self.classifier = binary_classifier\n",
"\n",
" def call(self, inputs):\n",
" features = self.dense(inputs)\n",
" return self.classifier(features)\n",
"\n",
"model = MyModel()"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"#### Remember: Use the right tool for the job"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"### Using built-in training and evaluation loops"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"from keras.datasets import mnist\n",
"\n",
"def get_mnist_model():\n",
" inputs = keras.Input(shape=(28 * 28,))\n",
" features = layers.Dense(512, activation=\"relu\")(inputs)\n",
" features = layers.Dropout(0.5)(features)\n",
" outputs = layers.Dense(10, activation=\"softmax\")(features)\n",
" model = keras.Model(inputs, outputs)\n",
" return model\n",
"\n",
"(images, labels), (test_images, test_labels) = mnist.load_data()\n",
"images = images.reshape((60000, 28 * 28)).astype(\"float32\") / 255\n",
"test_images = test_images.reshape((10000, 28 * 28)).astype(\"float32\") / 255\n",
"train_images, val_images = images[10000:], images[:10000]\n",
"train_labels, val_labels = labels[10000:], labels[:10000]\n",
"\n",
"model = get_mnist_model()\n",
"model.compile(\n",
" optimizer=\"adam\",\n",
" loss=\"sparse_categorical_crossentropy\",\n",
" metrics=[\"accuracy\"],\n",
")\n",
"model.fit(\n",
" train_images,\n",
" train_labels,\n",
" epochs=3,\n",
" validation_data=(val_images, val_labels),\n",
")\n",
"test_metrics = model.evaluate(test_images, test_labels)\n",
"predictions = model.predict(test_images)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"#### Writing your own metrics"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"from keras import ops\n",
"\n",
"class RootMeanSquaredError(keras.metrics.Metric):\n",
" def __init__(self, name=\"rmse\", **kwargs):\n",
" super().__init__(name=name, **kwargs)\n",
" self.mse_sum = self.add_weight(name=\"mse_sum\", initializer=\"zeros\")\n",
" self.total_samples = self.add_weight(\n",
" name=\"total_samples\", initializer=\"zeros\"\n",
" )\n",
"\n",
" def update_state(self, y_true, y_pred, sample_weight=None):\n",
" y_true = ops.one_hot(y_true, num_classes=ops.shape(y_pred)[1])\n",
" mse = ops.sum(ops.square(y_true - y_pred))\n",
" self.mse_sum.assign_add(mse)\n",
" num_samples = ops.shape(y_pred)[0]\n",
" self.total_samples.assign_add(num_samples)\n",
"\n",
" def result(self):\n",
" return ops.sqrt(self.mse_sum / self.total_samples)\n",
"\n",
" def reset_state(self):\n",
" self.mse_sum.assign(0.)\n",
" self.total_samples.assign(0.)"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model = get_mnist_model()\n",
"model.compile(\n",
" optimizer=\"adam\",\n",
" loss=\"sparse_categorical_crossentropy\",\n",
" metrics=[\"accuracy\", RootMeanSquaredError()],\n",
")\n",
"model.fit(\n",
" train_images,\n",
" train_labels,\n",
" epochs=3,\n",
" validation_data=(val_images, val_labels),\n",
")\n",
"test_metrics = model.evaluate(test_images, test_labels)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"#### Using callbacks"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### The EarlyStopping and ModelCheckpoint callbacks"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"callbacks_list = [\n",
" keras.callbacks.EarlyStopping(\n",
" monitor=\"accuracy\",\n",
" patience=1,\n",
" ),\n",
" keras.callbacks.ModelCheckpoint(\n",
" filepath=\"checkpoint_path.keras\",\n",
" monitor=\"val_loss\",\n",
" save_best_only=True,\n",
" ),\n",
"]\n",
"model = get_mnist_model()\n",
"model.compile(\n",
" optimizer=\"adam\",\n",
" loss=\"sparse_categorical_crossentropy\",\n",
" metrics=[\"accuracy\"],\n",
")\n",
"model.fit(\n",
" train_images,\n",
" train_labels,\n",
" epochs=10,\n",
" callbacks=callbacks_list,\n",
" validation_data=(val_images, val_labels),\n",
")"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model = keras.models.load_model(\"checkpoint_path.keras\")"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"#### Writing your own callbacks"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"from matplotlib import pyplot as plt\n",
"\n",
"class LossHistory(keras.callbacks.Callback):\n",
" def on_train_begin(self, logs):\n",
" self.per_batch_losses = []\n",
"\n",
" def on_batch_end(self, batch, logs):\n",
" self.per_batch_losses.append(logs.get(\"loss\"))\n",
"\n",
" def on_epoch_end(self, epoch, logs):\n",
" plt.clf()\n",
" plt.plot(\n",
" range(len(self.per_batch_losses)),\n",
" self.per_batch_losses,\n",
" label=\"Training loss for each batch\",\n",
" )\n",
" plt.xlabel(f\"Batch (epoch {epoch})\")\n",
" plt.ylabel(\"Loss\")\n",
" plt.legend()\n",
" plt.savefig(f\"plot_at_epoch_{epoch}\", dpi=300)\n",
" self.per_batch_losses = []"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model = get_mnist_model()\n",
"model.compile(\n",
" optimizer=\"adam\",\n",
" loss=\"sparse_categorical_crossentropy\",\n",
" metrics=[\"accuracy\"],\n",
")\n",
"model.fit(\n",
" train_images,\n",
" train_labels,\n",
" epochs=10,\n",
" callbacks=[LossHistory()],\n",
" validation_data=(val_images, val_labels),\n",
")"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"#### Monitoring and visualization with TensorBoard"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"model = get_mnist_model()\n",
"model.compile(\n",
" optimizer=\"adam\",\n",
" loss=\"sparse_categorical_crossentropy\",\n",
" metrics=[\"accuracy\"],\n",
")\n",
"\n",
"tensorboard = keras.callbacks.TensorBoard(\n",
" log_dir=\"/full_path_to_your_log_dir\",\n",
")\n",
"model.fit(\n",
" train_images,\n",
" train_labels,\n",
" epochs=10,\n",
" validation_data=(val_images, val_labels),\n",
" callbacks=[tensorboard],\n",
")"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%load_ext tensorboard\n",
"%tensorboard --logdir /full_path_to_your_log_dir"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"### Writing your own training and evaluation loops"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"#### Training vs. inference"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"#### Writing custom training step functions"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### A TensorFlow training step function"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend tensorflow\n",
"import tensorflow as tf\n",
"\n",
"model = get_mnist_model()\n",
"loss_fn = keras.losses.SparseCategoricalCrossentropy()\n",
"optimizer = keras.optimizers.Adam()\n",
"\n",
"def train_step(inputs, targets):\n",
" with tf.GradientTape() as tape:\n",
" predictions = model(inputs, training=True)\n",
" loss = loss_fn(targets, predictions)\n",
" gradients = tape.gradient(loss, model.trainable_weights)\n",
" optimizer.apply(gradients, model.trainable_weights)\n",
" return loss"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend tensorflow\n",
"batch_size = 32\n",
"inputs = train_images[:batch_size]\n",
"targets = train_labels[:batch_size]\n",
"loss = train_step(inputs, targets)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### A PyTorch training step function"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend torch\n",
"import torch\n",
"\n",
"model = get_mnist_model()\n",
"loss_fn = keras.losses.SparseCategoricalCrossentropy()\n",
"optimizer = keras.optimizers.Adam()\n",
"\n",
"def train_step(inputs, targets):\n",
" predictions = model(inputs, training=True)\n",
" loss = loss_fn(targets, predictions)\n",
" loss.backward()\n",
" gradients = [weight.value.grad for weight in model.trainable_weights]\n",
" with torch.no_grad():\n",
" optimizer.apply(gradients, model.trainable_weights)\n",
" model.zero_grad()\n",
" return loss"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend torch\n",
"batch_size = 32\n",
"inputs = train_images[:batch_size]\n",
"targets = train_labels[:batch_size]\n",
"loss = train_step(inputs, targets)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### A JAX training step function"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend jax\n",
"model = get_mnist_model()\n",
"loss_fn = keras.losses.SparseCategoricalCrossentropy()\n",
"\n",
"def compute_loss_and_updates(\n",
" trainable_variables, non_trainable_variables, inputs, targets\n",
"):\n",
" outputs, non_trainable_variables = model.stateless_call(\n",
" trainable_variables, non_trainable_variables, inputs, training=True\n",
" )\n",
" loss = loss_fn(targets, outputs)\n",
" return loss, non_trainable_variables"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend jax\n",
"import jax\n",
"\n",
"grad_fn = jax.value_and_grad(compute_loss_and_updates, has_aux=True)"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend jax\n",
"optimizer = keras.optimizers.Adam()\n",
"optimizer.build(model.trainable_variables)\n",
"\n",
"def train_step(state, inputs, targets):\n",
" (trainable_variables, non_trainable_variables, optimizer_variables) = state\n",
" (loss, non_trainable_variables), grads = grad_fn(\n",
" trainable_variables, non_trainable_variables, inputs, targets\n",
" )\n",
" trainable_variables, optimizer_variables = optimizer.stateless_apply(\n",
" optimizer_variables, grads, trainable_variables\n",
" )\n",
" return loss, (\n",
" trainable_variables,\n",
" non_trainable_variables,\n",
" optimizer_variables,\n",
" )"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend jax\n",
"batch_size = 32\n",
"inputs = train_images[:batch_size]\n",
"targets = train_labels[:batch_size]\n",
"\n",
"trainable_variables = [v.value for v in model.trainable_variables]\n",
"non_trainable_variables = [v.value for v in model.non_trainable_variables]\n",
"optimizer_variables = [v.value for v in optimizer.variables]\n",
"\n",
"state = (trainable_variables, non_trainable_variables, optimizer_variables)\n",
"loss, state = train_step(state, inputs, targets)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"#### Low-level usage of metrics"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"from keras import ops\n",
"\n",
"metric = keras.metrics.SparseCategoricalAccuracy()\n",
"targets = ops.array([0, 1, 2])\n",
"predictions = ops.array([[1, 0, 0], [0, 1, 0], [0, 0, 1]])\n",
"metric.update_state(targets, predictions)\n",
"current_result = metric.result()\n",
"print(f\"result: {current_result:.2f}\")"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"values = ops.array([0, 1, 2, 3, 4])\n",
"mean_tracker = keras.metrics.Mean()\n",
"for value in values:\n",
" mean_tracker.update_state(value)\n",
"print(f\"Mean of values: {mean_tracker.result():.2f}\")"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"metric = keras.metrics.SparseCategoricalAccuracy()\n",
"targets = ops.array([0, 1, 2])\n",
"predictions = ops.array([[1, 0, 0], [0, 1, 0], [0, 0, 1]])\n",
"\n",
"metric_variables = metric.variables\n",
"metric_variables = metric.stateless_update_state(\n",
" metric_variables, targets, predictions\n",
")\n",
"current_result = metric.stateless_result(metric_variables)\n",
"print(f\"result: {current_result:.2f}\")\n",
"\n",
"metric_variables = metric.stateless_reset_state()"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"#### Using fit() with a custom training loop"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### Customizing fit() with TensorFlow"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend tensorflow\n",
"import keras\n",
"from keras import layers\n",
"\n",
"loss_fn = keras.losses.SparseCategoricalCrossentropy()\n",
"loss_tracker = keras.metrics.Mean(name=\"loss\")\n",
"\n",
"class CustomModel(keras.Model):\n",
" def train_step(self, data):\n",
" inputs, targets = data\n",
" with tf.GradientTape() as tape:\n",
" predictions = self(inputs, training=True)\n",
" loss = loss_fn(targets, predictions)\n",
" gradients = tape.gradient(loss, self.trainable_weights)\n",
" self.optimizer.apply(gradients, self.trainable_weights)\n",
"\n",
" loss_tracker.update_state(loss)\n",
" return {\"loss\": loss_tracker.result()}\n",
"\n",
" @property\n",
" def metrics(self):\n",
" return [loss_tracker]"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend tensorflow\n",
"def get_custom_model():\n",
" inputs = keras.Input(shape=(28 * 28,))\n",
" features = layers.Dense(512, activation=\"relu\")(inputs)\n",
" features = layers.Dropout(0.5)(features)\n",
" outputs = layers.Dense(10, activation=\"softmax\")(features)\n",
" model = CustomModel(inputs, outputs)\n",
" model.compile(optimizer=keras.optimizers.Adam())\n",
" return model"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend tensorflow\n",
"model = get_custom_model()\n",
"model.fit(train_images, train_labels, epochs=3)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### Customizing fit() with PyTorch"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend torch\n",
"import keras\n",
"from keras import layers\n",
"\n",
"loss_fn = keras.losses.SparseCategoricalCrossentropy()\n",
"loss_tracker = keras.metrics.Mean(name=\"loss\")\n",
"\n",
"class CustomModel(keras.Model):\n",
" def train_step(self, data):\n",
" inputs, targets = data\n",
" predictions = self(inputs, training=True)\n",
" loss = loss_fn(targets, predictions)\n",
"\n",
" loss.backward()\n",
" trainable_weights = [v for v in self.trainable_weights]\n",
" gradients = [v.value.grad for v in trainable_weights]\n",
"\n",
" with torch.no_grad():\n",
" self.optimizer.apply(gradients, trainable_weights)\n",
"\n",
" loss_tracker.update_state(loss)\n",
" return {\"loss\": loss_tracker.result()}\n",
"\n",
" @property\n",
" def metrics(self):\n",
" return [loss_tracker]"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend torch\n",
"def get_custom_model():\n",
" inputs = keras.Input(shape=(28 * 28,))\n",
" features = layers.Dense(512, activation=\"relu\")(inputs)\n",
" features = layers.Dropout(0.5)(features)\n",
" outputs = layers.Dense(10, activation=\"softmax\")(features)\n",
" model = CustomModel(inputs, outputs)\n",
" model.compile(optimizer=keras.optimizers.Adam())\n",
" return model"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend torch\n",
"model = get_custom_model()\n",
"model.fit(train_images, train_labels, epochs=3)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### Customizing fit() with JAX"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend jax\n",
"import keras\n",
"from keras import layers\n",
"\n",
"loss_fn = keras.losses.SparseCategoricalCrossentropy()\n",
"\n",
"class CustomModel(keras.Model):\n",
" def compute_loss_and_updates(\n",
" self,\n",
" trainable_variables,\n",
" non_trainable_variables,\n",
" inputs,\n",
" targets,\n",
" training=False,\n",
" ):\n",
" predictions, non_trainable_variables = self.stateless_call(\n",
" trainable_variables,\n",
" non_trainable_variables,\n",
" inputs,\n",
" training=training,\n",
" )\n",
" loss = loss_fn(targets, predictions)\n",
" return loss, non_trainable_variables\n",
"\n",
" def train_step(self, state, data):\n",
" (\n",
" trainable_variables,\n",
" non_trainable_variables,\n",
" optimizer_variables,\n",
" metrics_variables,\n",
" ) = state\n",
" inputs, targets = data\n",
"\n",
" grad_fn = jax.value_and_grad(\n",
" self.compute_loss_and_updates, has_aux=True\n",
" )\n",
"\n",
" (loss, non_trainable_variables), grads = grad_fn(\n",
" trainable_variables,\n",
" non_trainable_variables,\n",
" inputs,\n",
" targets,\n",
" training=True,\n",
" )\n",
"\n",
" (\n",
" trainable_variables,\n",
" optimizer_variables,\n",
" ) = self.optimizer.stateless_apply(\n",
" optimizer_variables, grads, trainable_variables\n",
" )\n",
"\n",
" logs = {\"loss\": loss}\n",
" state = (\n",
" trainable_variables,\n",
" non_trainable_variables,\n",
" optimizer_variables,\n",
" metrics_variables,\n",
" )\n",
" return logs, state"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend jax\n",
"def get_custom_model():\n",
" inputs = keras.Input(shape=(28 * 28,))\n",
" features = layers.Dense(512, activation=\"relu\")(inputs)\n",
" features = layers.Dropout(0.5)(features)\n",
" outputs = layers.Dense(10, activation=\"softmax\")(features)\n",
" model = CustomModel(inputs, outputs)\n",
" model.compile(optimizer=keras.optimizers.Adam())\n",
" return model"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend jax\n",
"model = get_custom_model()\n",
"model.fit(train_images, train_labels, epochs=3)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"#### Handling metrics in a custom train_step()"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### train_step() metrics handling with TensorFlow"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend tensorflow\n",
"import keras\n",
"from keras import layers\n",
"\n",
"class CustomModel(keras.Model):\n",
" def train_step(self, data):\n",
" inputs, targets = data\n",
" with tf.GradientTape() as tape:\n",
" predictions = self(inputs, training=True)\n",
" loss = self.compute_loss(y=targets, y_pred=predictions)\n",
"\n",
" gradients = tape.gradient(loss, self.trainable_weights)\n",
" self.optimizer.apply(gradients, self.trainable_weights)\n",
"\n",
" for metric in self.metrics:\n",
" if metric.name == \"loss\":\n",
" metric.update_state(loss)\n",
" else:\n",
" metric.update_state(targets, predictions)\n",
"\n",
" return {m.name: m.result() for m in self.metrics}"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend tensorflow\n",
"def get_custom_model():\n",
" inputs = keras.Input(shape=(28 * 28,))\n",
" features = layers.Dense(512, activation=\"relu\")(inputs)\n",
" features = layers.Dropout(0.5)(features)\n",
" outputs = layers.Dense(10, activation=\"softmax\")(features)\n",
" model = CustomModel(inputs, outputs)\n",
" model.compile(\n",
" optimizer=keras.optimizers.Adam(),\n",
" loss=keras.losses.SparseCategoricalCrossentropy(),\n",
" metrics=[keras.metrics.SparseCategoricalAccuracy()],\n",
" )\n",
" return model\n",
"\n",
"model = get_custom_model()\n",
"model.fit(train_images, train_labels, epochs=3)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### train_step() metrics handling with PyTorch"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend torch\n",
"import keras\n",
"from keras import layers\n",
"\n",
"class CustomModel(keras.Model):\n",
" def train_step(self, data):\n",
" inputs, targets = data\n",
" predictions = self(inputs, training=True)\n",
" loss = self.compute_loss(y=targets, y_pred=predictions)\n",
"\n",
" loss.backward()\n",
" trainable_weights = [v for v in self.trainable_weights]\n",
" gradients = [v.value.grad for v in trainable_weights]\n",
"\n",
" with torch.no_grad():\n",
" self.optimizer.apply(gradients, trainable_weights)\n",
"\n",
" for metric in self.metrics:\n",
" if metric.name == \"loss\":\n",
" metric.update_state(loss)\n",
" else:\n",
" metric.update_state(targets, predictions)\n",
"\n",
" return {m.name: m.result() for m in self.metrics}"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend torch\n",
"def get_custom_model():\n",
" inputs = keras.Input(shape=(28 * 28,))\n",
" features = layers.Dense(512, activation=\"relu\")(inputs)\n",
" features = layers.Dropout(0.5)(features)\n",
" outputs = layers.Dense(10, activation=\"softmax\")(features)\n",
" model = CustomModel(inputs, outputs)\n",
" model.compile(\n",
" optimizer=keras.optimizers.Adam(),\n",
" loss=keras.losses.SparseCategoricalCrossentropy(),\n",
" metrics=[keras.metrics.SparseCategoricalAccuracy()],\n",
" )\n",
" return model\n",
"\n",
"model = get_custom_model()\n",
"model.fit(train_images, train_labels, epochs=3)"
]
},
{
"cell_type": "markdown",
"metadata": {
"colab_type": "text"
},
"source": [
"##### train_step() metrics handling with JAX"
]
},
{
"cell_type": "code",
"execution_count": 0,
"metadata": {
"colab_type": "code"
},
"outputs": [],
"source": [
"%%backend jax\n",
"import keras\n",
"from keras import layers\n",
"\n",
"class CustomModel(keras.Model):\n",
" def compute_loss_and_updates(\n",
" self,\n",
" trainable_variables,\n",
" non_trainable_variables,\n",
" inputs,\n",
" targets,\n",
" training=False,\n",
" ):\n",
" predictions, non_trainable_variables = self.stateless_call(\n",
" trainable_variables,\n",
" non_trainable_variables,\n",
" inputs,\n",
" training=training,\n",
" )\n",
" loss = self.compute_loss(y=targets, y_pred=predictions)\n",
" return loss, (predictions, non_trainable_variables)\n",
"\n",
" def train_step(self, state, data):\n",
" (\n",
" trainable_variables,\n",
" non_trainable_variables,\n",
" optimizer_variables,\n",
" metrics_variables,\n",
" ) = state\n",
" inputs, targets = data\n",
"\n",
" grad_fn = jax.value_and_grad(\n",
" self.compute_loss_and_updates, has_aux=True\n",
" )\n",
"\n",
" (loss, (predictions, non_trainable_variables)), grads = grad_fn(\n",
" trainable_variables,\n",
" non_trainable_variables,\n",
" inputs,\n",
" targets,\n",
" training=True,\n",
" )\n",
" (\n",
" trainable_variables,\n",
" optimizer_variables,\n",
" ) = self.optimizer.stateless_apply(\n",
" optimizer_variables, grads, trainable_variables\n",
" )\n",
"\n",
" new_metrics_vars = []\n",
" logs = {}\n",
" for metric in self.metrics:\n",
" num_prev = len(new_metrics_vars)\n",
" num_current = len(metric.variables)\n",
" current_vars = metrics_variables[num_prev : num_prev + num_current]\n",
" if metric.name == \"loss\":\n",
" current_vars = metric.stateless_update_state(current_vars, loss)\n",
" else:\n",
" current_vars = metric.stateless_update_state(\n",
" current_vars, targets, predictions\n",
" )\n",
" logs[metric.name] = metric.stateless_result(current_vars)\n",
" new_metrics_vars += current_vars\n",
"\n",
" state = (\n",
" trainable_variables,\n",
" non_trainable_variables,\n",
" optimizer_variables,\n",
" new_metrics_vars,\n",
" )\n",
" return logs, state"
]
}
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