# LRScheduler

Source: https://www.tensorplay.cn/docs/generated/tensorplay.optim.lr_scheduler.LRScheduler.html

# LRScheduler

class tensorplay.optim.lr_scheduler.LRScheduler(optimizer: [Optimizer](tensorplay.optim.optimizer.Optimizer.html#tensorplay.optim.optimizer.Optimizer), last_epoch: [int](https://docs.python.org/3/library/functions.html#int) = -1)[[source]](../_modules/tensorplay/optim/lr_scheduler.html#LRScheduler)

Base class for all learning rate schedulers.

Subclasses implement [get_lr()](#tensorplay.optim.lr_scheduler.LRScheduler.get_lr) and optionally override [step()](#tensorplay.optim.lr_scheduler.LRScheduler.step) to
define scheduling behavior.

Parameters:

- optimizer ([Optimizer](tensorplay.optim.optimizer.Optimizer.html#tensorplay.optim.optimizer.Optimizer)) – The optimizer this scheduler will adjust the learning rates of.

- last_epoch ([int](https://docs.python.org/3/library/functions.html#int)) – Index of the last epoch seen by the scheduler. Use -1 (default) to initialize the scheduler. Only use a non-default value when restoring this scheduler from a saved checkpoint.

Warning

Initializing a scheduler overwrites its optimizer’s
param_group["lr"]s. When restoring a checkpoint, initialize the
scheduler before calling your optimizer’s
load_state_dict() to avoid overwriting the
loaded learning rates.

get_last_lr() → [list](https://docs.python.org/3/library/stdtypes.html#list)[[float](https://docs.python.org/3/library/functions.html#float) | TensorBase][[source]](../_modules/tensorplay/optim/lr_scheduler.html#LRScheduler.get_last_lr)

Get the most recent learning rates computed by this scheduler.

Returns:

A [list](https://docs.python.org/3/library/stdtypes.html#list) of learning rates with entries
for each of the optimizer’s
param_groups, with the same types as
their group["lr"]s.

Return type:

[list](https://docs.python.org/3/library/stdtypes.html#list)[[float](https://docs.python.org/3/library/functions.html#float) | Tensor]

Note

The returned Tensors are copies, and never alias
the optimizer’s group["lr"]s.

get_lr() → [list](https://docs.python.org/3/library/stdtypes.html#list)[[float](https://docs.python.org/3/library/functions.html#float) | TensorBase][[source]](../_modules/tensorplay/optim/lr_scheduler.html#LRScheduler.get_lr)

Compute the next learning rate for each of the optimizer’s
param_groups.

Returns:

A [list](https://docs.python.org/3/library/stdtypes.html#list) of learning rates for each of
the optimizer’s param_groups with the
same types as their current group["lr"]s.

Return type:

[list](https://docs.python.org/3/library/stdtypes.html#list)[[float](https://docs.python.org/3/library/functions.html#float) | Tensor]

Note

If you’re trying to inspect the most recent learning rate, use
[get_last_lr()](#tensorplay.optim.lr_scheduler.LRScheduler.get_last_lr) instead.

Note

The returned Tensors are copies, and never alias
the optimizer’s group["lr"]s.

load_state_dict(state_dict: [dict](https://docs.python.org/3/library/stdtypes.html#dict)[[str](https://docs.python.org/3/library/stdtypes.html#str), [Any](https://docs.python.org/3/library/typing.html#typing.Any)]) → [None](https://docs.python.org/3/library/constants.html#None)[[source]](../_modules/tensorplay/optim/lr_scheduler.html#LRScheduler.load_state_dict)

Load the scheduler’s state.

Parameters:

state_dict ([dict](https://docs.python.org/3/library/stdtypes.html#dict)) – scheduler state. Should be an object returned
from a call to [state_dict()](#tensorplay.optim.lr_scheduler.LRScheduler.state_dict).

state_dict() → [dict](https://docs.python.org/3/library/stdtypes.html#dict)[[str](https://docs.python.org/3/library/stdtypes.html#str), [Any](https://docs.python.org/3/library/typing.html#typing.Any)][[source]](../_modules/tensorplay/optim/lr_scheduler.html#LRScheduler.state_dict)

Return the state of the scheduler as a [dict](https://docs.python.org/3/library/stdtypes.html#dict).

It contains an entry for every variable in self.__dict__ which
is not the optimizer.

step(epoch: [int](https://docs.python.org/3/library/functions.html#int) | [None](https://docs.python.org/3/library/constants.html#None) = None) → [None](https://docs.python.org/3/library/constants.html#None)[[source]](../_modules/tensorplay/optim/lr_scheduler.html#LRScheduler.step)

Step the scheduler.

Parameters:

epoch ([int](https://docs.python.org/3/library/functions.html#int), optional) – 
Deprecated since version 1.4: If provided, sets last_epoch to epoch and uses
_get_closed_form_lr() if it is available. This is not
universally supported. Use [step()](#tensorplay.optim.lr_scheduler.LRScheduler.step) without arguments
instead.

Note

Call this method after calling the optimizer’s
step().