tf.keras.callbacks.LearningRateScheduler

Learning rate scheduler.

Inherits From: Callback

tf.keras.callbacks.LearningRateScheduler(
    schedule, verbose=0
)

At the beginning of every epoch, this callback gets the updated learning rate value from schedule function provided at __init__, with the current epoch and current learning rate, and applies the updated learning rate on the optimizer.

schedule a function that takes an epoch index (integer, indexed from 0) and current learning rate (float) as inputs and returns a new learning rate as output (float).
verbose int. 0: quiet, 1: update messages.

Example:

# This function keeps the initial learning rate for the first ten epochs
# and decreases it exponentially after that.
def scheduler(epoch, lr):
  if epoch < 10:
    return lr
  else:
    return lr * tf.math.exp(-0.1)

model = tf.keras.models.Sequential([tf.keras.layers.Dense(10)])
model.compile(tf.keras.optimizers.SGD(), loss='mse')
round(model.optimizer.lr.numpy(), 5)
0.01
 
callback = tf.keras.callbacks.LearningRateScheduler(scheduler)
history = model.fit(np.arange(100).reshape(5, 20), np.zeros(5),
                    epochs=15, callbacks=[callback], verbose=0)
round(model.optimizer.lr.numpy(), 5)
0.00607

Methods

set_model

View source

set_model(
    model
)

set_params

View source

set_params(
    params
)