import tensorflow_core as tfc
from tensorflow_core.python.keras.callbacks import LearningRateScheduler
num_epochs =20
learning_rate=0.3
#定义学习率衰减函数
def scheduler(epoch):
if epoch < num_epochs * 0.4:
return learning_rate
if epoch < num_epochs * 0.8:
return learning_rate * 0.1
return learning_rate * 0.01
change_Lr = tfc.python.keras.callbacks.LearningRateScheduler(scheduler)
history = model.fit_generator(train_generator,
steps_per_epoch=10,
epochs=epochs,
validation_data=valid_generator,
validation_steps=10
,callbacks=[change_Lr])