Source code for rlgraph.components.optimizers.horovod_optimizer
# Copyright 2018 The RLgraph authors. All Rights Reserved.
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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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# http://www.apache.org/licenses/LICENSE-2.0
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# Unless required by applicable law or agreed to in writing, software
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# ==============================================================================
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from rlgraph import get_backend, get_distributed_backend
from rlgraph.components.optimizers.optimizer import Optimizer
if get_backend() == "tf" and get_distributed_backend() == "horovod":
import horovod.tensorflow as hvd
elif get_backend() == "pytorch" and get_backend() == "horovod":
import horovod.pytorch as hvd
[docs]class HorovodOptimizer(Optimizer):
"""
This Optimizer provides a wrapper for the horovod optimizer package:
https://github.com/uber/horovod
Horovod is meant to be used as an alternative to distributed TensorFlow as it implements
communication in a different way, as explained in the Horovod paper:
arXiv:1802.05799
This Horovod Optimizer expects a local LocalOptimizer spec (tensorflow) as input.
"""
def __init__(self, local_optimizer=None, **kwargs):
"""
Initializes a distributed horovod optimizer by wrapping a local optimizer.
Args:
local_optimizer (Optional[dict,LocalOptimizer]): The spec-dict for the wrapped LocalOptimizer object or
a LocalOptimizer object itself.
"""
super(HorovodOptimizer, self).__init__(**kwargs)
# Create the horovod wrapper.
wrapped_local_optimizer = Optimizer.from_spec(local_optimizer)
self.local_optimizer = hvd.DistributedOptimizer(wrapped_local_optimizer)
@api
def step(self, variables, loss, *inputs):
grads_and_vars = self._graph_fn_calculate_gradients(variables, loss, *inputs)
return self._graph_fn_apply_gradients(grads_and_vars)
def _graph_fn_calculate_gradients(self, variables, loss, *inputs):
return self.local_optimizer._graph_fn_calculate_gradients(variables, loss, *inputs)
def _graph_fn_apply_gradients(self, grads_and_vars):
return self.local_optimizer._graph_fn_apply_gradients(grads_and_vars)