Source code for objax.optimizer.sgd

# Copyright 2020 Google LLC
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# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
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#     https://www.apache.org/licenses/LICENSE-2.0
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__all__ = ['SGD']

from typing import List

from objax.module import Module, ModuleList
from objax.typing import JaxArray
from objax.util import class_name
from objax.variable import TrainRef, TrainVar, VarCollection


[docs] class SGD(Module): """Stochastic Gradient Descent (SGD) optimizer."""
[docs] def __init__(self, vc: VarCollection): """Constructor for SGD optimizer. Args: vc: collection of variables to optimize. """ self.train_vars = ModuleList(TrainRef(x) for x in vc.subset(TrainVar))
[docs] def __call__(self, lr: float, grads: List[JaxArray]): """Updates variables based on SGD algorithm. Args: lr: the learning rate. grads: the gradients to apply. """ assert len(grads) == len(self.train_vars), 'Expecting as many gradients as trainable variables' for g, p in zip(grads, self.train_vars): p.value -= lr * g
def __repr__(self): return f'{class_name(self)}()'