Introduction to the Keras Tuner

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Overview

The Keras Tuner is a library that helps you pick the optimal set of hyperparameters for your TensorFlow program. The process of selecting the right set of hyperparameters for your machine learning (ML) application is called hyperparameter tuning or hypertuning.

Hyperparameters are the variables that govern the training process and the topology of an ML model. These variables remain constant over the training process and directly impact the performance of your ML program. Hyperparameters are of two types:

  1. Model hyperparameters which influence model selection such as the number and width of hidden layers
  2. Algorithm hyperparameters which influence the speed and quality of the learning algorithm such as the learning rate for Stochastic Gradient Descent (SGD) and the number of nearest neighbors for a k Nearest Neighbors (KNN) classifier

In this tutorial, you will use the Keras Tuner to perform hypertuning for an image classification application.

Setup

import tensorflow as tf
from tensorflow import keras

Install and import the Keras Tuner.

pip install -q -U keras-tuner
import keras_tuner as kt

Download and prepare the dataset

In this tutorial, you will use the Keras Tuner to find the best hyperparameters for a machine learning model that classifies images of clothing from the Fashion MNIST dataset.

Load the data.

(img_train, label_train), (img_test, label_test) = keras.datasets.fashion_mnist.load_data()
# Normalize pixel values between 0 and 1
img_train = img_train.astype('float32') / 255.0
img_test = img_test.astype('float32') / 255.0

Define the model

When you build a model for hypertuning, you also define the hyperparameter search space in addition to the model architecture. The model you set up for hypertuning is called a hypermodel.

You can define a hypermodel through two approaches:

  • By using a model builder function
  • By subclassing the HyperModel class of the Keras Tuner API

You can also use two pre-defined HyperModel classes - HyperXception and HyperResNet for computer vision applications.

In this tutorial, you use a model builder function to define the image classification model. The model builder function returns a compiled model and uses hyperparameters you define inline to hypertune the model.

def model_builder(hp):
  model = keras.Sequential()
  model.add(keras.layers.Flatten(input_shape=(28, 28)))

  # Tune the number of units in the first Dense layer
  # Choose an optimal value between 32-512
  hp_units = hp.Int('units', min_value=32, max_value=512, step=32)
  model.add(keras.layers.Dense(units=hp_units, activation='relu'))
  model.add(keras.layers.Dense(10))

  # Tune the learning rate for the optimizer
  # Choose an optimal value from 0.01, 0.001, or 0.0001
  hp_learning_rate = hp.Choice('learning_rate', values=[1e-2, 1e-3, 1e-4])

  model.compile(optimizer=keras.optimizers.Adam(learning_rate=hp_learning_rate),
                loss=keras.losses.SparseCategoricalCrossentropy(from_logits=True),
                metrics=['accuracy'])

  return model

Instantiate the tuner and perform hypertuning

Instantiate the tuner to perform the hypertuning. The Keras Tuner has four tuners available - RandomSearch, Hyperband, BayesianOptimization, and Sklearn. In this tutorial, you use the Hyperband tuner.

To instantiate the Hyperband tuner, you must specify the hypermodel, the objective to optimize and the maximum number of epochs to train (max_epochs).

tuner = kt.Hyperband(model_builder,
                     objective='val_accuracy',
                     max_epochs=10,
                     factor=3,
                     directory='my_dir',
                     project_name='intro_to_kt')
/tmpfs/src/tf_docs_env/lib/python3.13/site-packages/keras/src/layers/reshaping/flatten.py:37: UserWarning: Do not pass an `input_shape`/`input_dim` argument to a layer. When using Sequential models, prefer using an `Input(shape)` object as the first layer in the model instead.
  super().__init__(**kwargs)

The Hyperband tuning algorithm uses adaptive resource allocation and early-stopping to quickly converge on a high-performing model. This is done using a sports championship style bracket. The algorithm trains a large number of models for a few epochs and carries forward only the top-performing half of models to the next round. Hyperband determines the number of models to train in a bracket by computing 1 + logfactor(max_epochs) and rounding it up to the nearest integer.

Create a callback to stop training early after reaching a certain value for the validation loss.

stop_early = tf.keras.callbacks.EarlyStopping(monitor='val_loss', patience=5)

Run the hyperparameter search. The arguments for the search method are the same as those used for tf.keras.model.fit in addition to the callback above.

tuner.search(img_train, label_train, epochs=50, validation_split=0.2, callbacks=[stop_early])

# Get the optimal hyperparameters
best_hps=tuner.get_best_hyperparameters(num_trials=1)[0]

print(f"""
The hyperparameter search is complete. The optimal number of units in the first densely-connected
layer is {best_hps.get('units')} and the optimal learning rate for the optimizer
is {best_hps.get('learning_rate')}.
""")
Trial 30 Complete [00h 00m 47s]
val_accuracy: 0.890749990940094

Best val_accuracy So Far: 0.8930000066757202
Total elapsed time: 00h 10m 28s

The hyperparameter search is complete. The optimal number of units in the first densely-connected
layer is 480 and the optimal learning rate for the optimizer
is 0.001.

Train the model

Find the optimal number of epochs to train the model with the hyperparameters obtained from the search.

# Build the model with the optimal hyperparameters and train it on the data for 50 epochs
model = tuner.hypermodel.build(best_hps)
history = model.fit(img_train, label_train, epochs=50, validation_split=0.2)

val_acc_per_epoch = history.history['val_accuracy']
best_epoch = val_acc_per_epoch.index(max(val_acc_per_epoch)) + 1
print('Best epoch: %d' % (best_epoch,))
Epoch 1/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 6s 3ms/step - accuracy: 0.8243 - loss: 0.4927 - val_accuracy: 0.8531 - val_loss: 0.3939
Epoch 2/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.8654 - loss: 0.3709 - val_accuracy: 0.8685 - val_loss: 0.3533
Epoch 3/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.8770 - loss: 0.3328 - val_accuracy: 0.8777 - val_loss: 0.3441
Epoch 4/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.8883 - loss: 0.3053 - val_accuracy: 0.8715 - val_loss: 0.3482
Epoch 5/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.8930 - loss: 0.2882 - val_accuracy: 0.8736 - val_loss: 0.3397
Epoch 6/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.8982 - loss: 0.2727 - val_accuracy: 0.8788 - val_loss: 0.3322
Epoch 7/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9039 - loss: 0.2570 - val_accuracy: 0.8814 - val_loss: 0.3370
Epoch 8/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9087 - loss: 0.2461 - val_accuracy: 0.8888 - val_loss: 0.3166
Epoch 9/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9135 - loss: 0.2339 - val_accuracy: 0.8873 - val_loss: 0.3226
Epoch 10/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9164 - loss: 0.2247 - val_accuracy: 0.8879 - val_loss: 0.3287
Epoch 11/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9197 - loss: 0.2141 - val_accuracy: 0.8909 - val_loss: 0.3270
Epoch 12/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9234 - loss: 0.2061 - val_accuracy: 0.8892 - val_loss: 0.3295
Epoch 13/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9240 - loss: 0.1991 - val_accuracy: 0.8957 - val_loss: 0.3121
Epoch 14/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9285 - loss: 0.1917 - val_accuracy: 0.8911 - val_loss: 0.3199
Epoch 15/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9286 - loss: 0.1847 - val_accuracy: 0.8889 - val_loss: 0.3321
Epoch 16/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9314 - loss: 0.1806 - val_accuracy: 0.8965 - val_loss: 0.3282
Epoch 17/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9348 - loss: 0.1727 - val_accuracy: 0.8979 - val_loss: 0.3327
Epoch 18/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9370 - loss: 0.1659 - val_accuracy: 0.8934 - val_loss: 0.3370
Epoch 19/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9393 - loss: 0.1637 - val_accuracy: 0.8924 - val_loss: 0.3594
Epoch 20/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9422 - loss: 0.1533 - val_accuracy: 0.8953 - val_loss: 0.3468
Epoch 21/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9436 - loss: 0.1504 - val_accuracy: 0.8954 - val_loss: 0.3520
Epoch 22/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9445 - loss: 0.1452 - val_accuracy: 0.8950 - val_loss: 0.3509
Epoch 23/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9465 - loss: 0.1409 - val_accuracy: 0.8900 - val_loss: 0.3724
Epoch 24/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9479 - loss: 0.1381 - val_accuracy: 0.8919 - val_loss: 0.3864
Epoch 25/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9493 - loss: 0.1327 - val_accuracy: 0.8974 - val_loss: 0.3671
Epoch 26/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9514 - loss: 0.1291 - val_accuracy: 0.8960 - val_loss: 0.3948
Epoch 27/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9521 - loss: 0.1258 - val_accuracy: 0.8909 - val_loss: 0.3980
Epoch 28/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9525 - loss: 0.1252 - val_accuracy: 0.8951 - val_loss: 0.3971
Epoch 29/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9562 - loss: 0.1191 - val_accuracy: 0.8899 - val_loss: 0.4191
Epoch 30/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9574 - loss: 0.1132 - val_accuracy: 0.8962 - val_loss: 0.3834
Epoch 31/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9579 - loss: 0.1120 - val_accuracy: 0.8924 - val_loss: 0.4119
Epoch 32/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9588 - loss: 0.1097 - val_accuracy: 0.8913 - val_loss: 0.4269
Epoch 33/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9590 - loss: 0.1067 - val_accuracy: 0.8950 - val_loss: 0.4153
Epoch 34/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9600 - loss: 0.1061 - val_accuracy: 0.8920 - val_loss: 0.4477
Epoch 35/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9605 - loss: 0.1038 - val_accuracy: 0.8929 - val_loss: 0.4493
Epoch 36/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9629 - loss: 0.1000 - val_accuracy: 0.8886 - val_loss: 0.4768
Epoch 37/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9631 - loss: 0.0993 - val_accuracy: 0.8960 - val_loss: 0.4590
Epoch 38/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9637 - loss: 0.0962 - val_accuracy: 0.8967 - val_loss: 0.4730
Epoch 39/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9658 - loss: 0.0910 - val_accuracy: 0.8917 - val_loss: 0.4724
Epoch 40/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9654 - loss: 0.0927 - val_accuracy: 0.8951 - val_loss: 0.4694
Epoch 41/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9660 - loss: 0.0894 - val_accuracy: 0.8917 - val_loss: 0.4923
Epoch 42/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9676 - loss: 0.0857 - val_accuracy: 0.8994 - val_loss: 0.4901
Epoch 43/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9686 - loss: 0.0835 - val_accuracy: 0.8878 - val_loss: 0.5240
Epoch 44/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9677 - loss: 0.0837 - val_accuracy: 0.8927 - val_loss: 0.5169
Epoch 45/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9694 - loss: 0.0832 - val_accuracy: 0.8924 - val_loss: 0.4892
Epoch 46/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9709 - loss: 0.0776 - val_accuracy: 0.8951 - val_loss: 0.5137
Epoch 47/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9705 - loss: 0.0792 - val_accuracy: 0.8888 - val_loss: 0.5718
Epoch 48/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9722 - loss: 0.0763 - val_accuracy: 0.8955 - val_loss: 0.5456
Epoch 49/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9695 - loss: 0.0814 - val_accuracy: 0.8963 - val_loss: 0.5219
Epoch 50/50
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9714 - loss: 0.0746 - val_accuracy: 0.8953 - val_loss: 0.5361
Best epoch: 42

Re-instantiate the hypermodel and train it with the optimal number of epochs from above.

hypermodel = tuner.hypermodel.build(best_hps)

# Retrain the model
hypermodel.fit(img_train, label_train, epochs=best_epoch, validation_split=0.2)
Epoch 1/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 6s 3ms/step - accuracy: 0.8259 - loss: 0.4944 - val_accuracy: 0.8562 - val_loss: 0.4065
Epoch 2/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.8634 - loss: 0.3684 - val_accuracy: 0.8703 - val_loss: 0.3623
Epoch 3/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.8767 - loss: 0.3325 - val_accuracy: 0.8814 - val_loss: 0.3374
Epoch 4/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.8861 - loss: 0.3072 - val_accuracy: 0.8756 - val_loss: 0.3473
Epoch 5/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.8925 - loss: 0.2889 - val_accuracy: 0.8742 - val_loss: 0.3556
Epoch 6/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.8980 - loss: 0.2726 - val_accuracy: 0.8876 - val_loss: 0.3083
Epoch 7/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9038 - loss: 0.2571 - val_accuracy: 0.8928 - val_loss: 0.3040
Epoch 8/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9081 - loss: 0.2448 - val_accuracy: 0.8892 - val_loss: 0.3099
Epoch 9/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9121 - loss: 0.2339 - val_accuracy: 0.8808 - val_loss: 0.3350
Epoch 10/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9170 - loss: 0.2231 - val_accuracy: 0.8857 - val_loss: 0.3231
Epoch 11/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9190 - loss: 0.2148 - val_accuracy: 0.8888 - val_loss: 0.3221
Epoch 12/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9223 - loss: 0.2083 - val_accuracy: 0.8877 - val_loss: 0.3356
Epoch 13/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9243 - loss: 0.1989 - val_accuracy: 0.8888 - val_loss: 0.3432
Epoch 14/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9281 - loss: 0.1909 - val_accuracy: 0.8948 - val_loss: 0.3078
Epoch 15/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9306 - loss: 0.1841 - val_accuracy: 0.8947 - val_loss: 0.3171
Epoch 16/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9333 - loss: 0.1781 - val_accuracy: 0.8848 - val_loss: 0.3515
Epoch 17/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9354 - loss: 0.1721 - val_accuracy: 0.8897 - val_loss: 0.3631
Epoch 18/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9375 - loss: 0.1677 - val_accuracy: 0.8918 - val_loss: 0.3421
Epoch 19/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9379 - loss: 0.1641 - val_accuracy: 0.8946 - val_loss: 0.3503
Epoch 20/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9392 - loss: 0.1596 - val_accuracy: 0.8957 - val_loss: 0.3479
Epoch 21/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9431 - loss: 0.1501 - val_accuracy: 0.8942 - val_loss: 0.3602
Epoch 22/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9456 - loss: 0.1453 - val_accuracy: 0.8967 - val_loss: 0.3681
Epoch 23/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9453 - loss: 0.1441 - val_accuracy: 0.8992 - val_loss: 0.3425
Epoch 24/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9469 - loss: 0.1397 - val_accuracy: 0.8878 - val_loss: 0.3858
Epoch 25/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9488 - loss: 0.1341 - val_accuracy: 0.8941 - val_loss: 0.3659
Epoch 26/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9519 - loss: 0.1291 - val_accuracy: 0.8940 - val_loss: 0.3780
Epoch 27/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9517 - loss: 0.1282 - val_accuracy: 0.8931 - val_loss: 0.4064
Epoch 28/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9517 - loss: 0.1262 - val_accuracy: 0.8928 - val_loss: 0.4119
Epoch 29/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9554 - loss: 0.1184 - val_accuracy: 0.8922 - val_loss: 0.4112
Epoch 30/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9562 - loss: 0.1170 - val_accuracy: 0.8952 - val_loss: 0.3910
Epoch 31/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9582 - loss: 0.1129 - val_accuracy: 0.8922 - val_loss: 0.4179
Epoch 32/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9580 - loss: 0.1103 - val_accuracy: 0.8923 - val_loss: 0.4191
Epoch 33/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9594 - loss: 0.1093 - val_accuracy: 0.8937 - val_loss: 0.4253
Epoch 34/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9587 - loss: 0.1066 - val_accuracy: 0.8963 - val_loss: 0.4137
Epoch 35/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9602 - loss: 0.1049 - val_accuracy: 0.8933 - val_loss: 0.4347
Epoch 36/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9621 - loss: 0.0995 - val_accuracy: 0.8928 - val_loss: 0.4444
Epoch 37/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9627 - loss: 0.0990 - val_accuracy: 0.8933 - val_loss: 0.4532
Epoch 38/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9641 - loss: 0.0957 - val_accuracy: 0.8906 - val_loss: 0.4658
Epoch 39/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9646 - loss: 0.0954 - val_accuracy: 0.8978 - val_loss: 0.4567
Epoch 40/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9654 - loss: 0.0910 - val_accuracy: 0.8941 - val_loss: 0.4912
Epoch 41/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 4s 3ms/step - accuracy: 0.9651 - loss: 0.0920 - val_accuracy: 0.8873 - val_loss: 0.5168
Epoch 42/42
1500/1500 ━━━━━━━━━━━━━━━━━━━━ 5s 3ms/step - accuracy: 0.9659 - loss: 0.0899 - val_accuracy: 0.8933 - val_loss: 0.5086
<keras.src.callbacks.history.History at 0x7fd44844add0>

To finish this tutorial, evaluate the hypermodel on the test data.

eval_result = hypermodel.evaluate(img_test, label_test)
print("[test loss, test accuracy]:", eval_result)
313/313 ━━━━━━━━━━━━━━━━━━━━ 2s 4ms/step - accuracy: 0.8885 - loss: 0.5407
[test loss, test accuracy]: [0.5406776070594788, 0.8884999752044678]

The my_dir/intro_to_kt directory contains detailed logs and checkpoints for every trial (model configuration) run during the hyperparameter search. If you re-run the hyperparameter search, the Keras Tuner uses the existing state from these logs to resume the search. To disable this behavior, pass an additional overwrite=True argument while instantiating the tuner.

Summary

In this tutorial, you learned how to use the Keras Tuner to tune hyperparameters for a model. To learn more about the Keras Tuner, check out these additional resources:

Also check out the HParams Dashboard in TensorBoard to interactively tune your model hyperparameters.