learning_rate_schedule_exponential_decay
A LearningRateSchedule that uses an exponential decay schedule
Description
A LearningRateSchedule that uses an exponential decay schedule
Usage
learning_rate_schedule_exponential_decay(
initial_learning_rate,
decay_steps,
decay_rate,
staircase = FALSE,
...,
name = NULL
) Arguments
| Arguments | Description |
|---|---|
| initial_learning_rate | A scalar float32 or float64 Tensor or a R number. The initial learning rate. |
| decay_steps | A scalar int32 or int64 Tensor or an R number. Must be positive. See the decay computation above. |
| decay_rate | A scalar float32 or float64 Tensor or an R number. The decay rate. |
| staircase | Boolean. If TRUE decay the learning rate at discrete intervals. |
| … | For backwards and forwards compatibility |
| name | String. Optional name of the operation. Defaults to ‘ExponentialDecay’. |
Details
When training a model, it is often useful to lower the learning rate as the training progresses. This schedule applies an exponential decay function to an optimizer step, given a provided initial learning rate. The schedule is a 1-arg callable that produces a decayed learning rate when passed the current optimizer step. This can be useful for changing the learning rate value across different invocations of optimizer functions. It is computed as: ```
decayed_learning_rate <- function(step)
initial_learning_rate * decay_rate ^ (step / decay_steps)
If the argument `staircase` is `TRUE`, then `step / decay_steps` is an integer division (`%/%`) and the decayed learning rate follows a staircase function. You can pass this schedule directly into a optimizer as the learning rate (see example) Example: When fitting a Keras model, decay every 100000 steps with a base of 0.96:
initial_learning_rate <- 0.1
lr_schedule <- learning_rate_schedule_exponential_decay(
initial_learning_rate,
decay_steps = 100000,
decay_rate = 0.96,
staircase = TRUE) model %>% compile(
optimizer= optimizer_sgd(learning_rate = lr_schedule),
loss = ‘sparse_categorical_crossentropy’,
metrics = ‘accuracy’)
model %>% fit(data, labels, epochs = 5)
```