text
stringlengths 0
4.99k
|
---|
Doing fine-tuning of the top layers when training seems to be plateauing
|
Sending email or instant message notifications when training ends or where a certain performance threshold is exceeded
|
Etc.
|
Callbacks can be passed as a list to your call to fit():
|
model = get_compiled_model()
|
callbacks = [
|
keras.callbacks.EarlyStopping(
|
# Stop training when `val_loss` is no longer improving
|
monitor="val_loss",
|
# "no longer improving" being defined as "no better than 1e-2 less"
|
min_delta=1e-2,
|
# "no longer improving" being further defined as "for at least 2 epochs"
|
patience=2,
|
verbose=1,
|
)
|
]
|
model.fit(
|
x_train,
|
y_train,
|
epochs=20,
|
batch_size=64,
|
callbacks=callbacks,
|
validation_split=0.2,
|
)
|
Epoch 1/20
|
625/625 [==============================] - 1s 1ms/step - loss: 0.6032 - sparse_categorical_accuracy: 0.8355 - val_loss: 0.2303 - val_sparse_categorical_accuracy: 0.9306
|
Epoch 2/20
|
625/625 [==============================] - 1s 1ms/step - loss: 0.1855 - sparse_categorical_accuracy: 0.9458 - val_loss: 0.1775 - val_sparse_categorical_accuracy: 0.9471
|
Epoch 3/20
|
625/625 [==============================] - 1s 1ms/step - loss: 0.1280 - sparse_categorical_accuracy: 0.9597 - val_loss: 0.1585 - val_sparse_categorical_accuracy: 0.9531
|
Epoch 4/20
|
625/625 [==============================] - 1s 1ms/step - loss: 0.0986 - sparse_categorical_accuracy: 0.9704 - val_loss: 0.1418 - val_sparse_categorical_accuracy: 0.9593
|
Epoch 5/20
|
625/625 [==============================] - 1s 1ms/step - loss: 0.0774 - sparse_categorical_accuracy: 0.9761 - val_loss: 0.1319 - val_sparse_categorical_accuracy: 0.9628
|
Epoch 6/20
|
625/625 [==============================] - 1s 1ms/step - loss: 0.0649 - sparse_categorical_accuracy: 0.9798 - val_loss: 0.1465 - val_sparse_categorical_accuracy: 0.9580
|
Epoch 00006: early stopping
|
<tensorflow.python.keras.callbacks.History at 0x14e899ad0>
|
Many built-in callbacks are available
|
There are many built-in callbacks already available in Keras, such as:
|
ModelCheckpoint: Periodically save the model.
|
EarlyStopping: Stop training when training is no longer improving the validation metrics.
|
TensorBoard: periodically write model logs that can be visualized in TensorBoard (more details in the section "Visualization").
|
CSVLogger: streams loss and metrics data to a CSV file.
|
etc.
|
See the callbacks documentation for the complete list.
|
Writing your own callback
|
You can create a custom callback by extending the base class keras.callbacks.Callback. A callback has access to its associated model through the class property self.model.
|
Make sure to read the complete guide to writing custom callbacks.
|
Here's a simple example saving a list of per-batch loss values during training:
|
class LossHistory(keras.callbacks.Callback):
|
def on_train_begin(self, logs):
|
self.per_batch_losses = []
|
def on_batch_end(self, batch, logs):
|
self.per_batch_losses.append(logs.get("loss"))
|
Checkpointing models
|
When you're training model on relatively large datasets, it's crucial to save checkpoints of your model at frequent intervals.
|
The easiest way to achieve this is with the ModelCheckpoint callback:
|
model = get_compiled_model()
|
callbacks = [
|
keras.callbacks.ModelCheckpoint(
|
# Path where to save the model
|
# The two parameters below mean that we will overwrite
|
# the current checkpoint if and only if
|
# the `val_loss` score has improved.
|
# The saved model name will include the current epoch.
|
filepath="mymodel_{epoch}",
|
save_best_only=True, # Only save a model if `val_loss` has improved.
|
monitor="val_loss",
|
verbose=1,
|
)
|
]
|
model.fit(
|
x_train, y_train, epochs=2, batch_size=64, callbacks=callbacks, validation_split=0.2
|
)
|
Epoch 1/2
|
625/625 [==============================] - 1s 1ms/step - loss: 0.6380 - sparse_categorical_accuracy: 0.8226 - val_loss: 0.2283 - val_sparse_categorical_accuracy: 0.9317
|
Epoch 00001: val_loss improved from inf to 0.22825, saving model to mymodel_1
|
INFO:tensorflow:Assets written to: mymodel_1/assets
|
Epoch 2/2
|
625/625 [==============================] - 1s 1ms/step - loss: 0.1787 - sparse_categorical_accuracy: 0.9466 - val_loss: 0.1877 - val_sparse_categorical_accuracy: 0.9440
|
Epoch 00002: val_loss improved from 0.22825 to 0.18768, saving model to mymodel_2
|
INFO:tensorflow:Assets written to: mymodel_2/assets
|
<tensorflow.python.keras.callbacks.History at 0x14e899b90>
|
The ModelCheckpoint callback can be used to implement fault-tolerance: the ability to restart training from the last saved state of the model in case training gets randomly interrupted. Here's a basic example:
|
import os
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.