mirror of
https://github.com/vale981/ray
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40 lines
1.4 KiB
Python
40 lines
1.4 KiB
Python
from typing import Optional, Any
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from ray.rllib.utils.framework import try_import_tf
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from ray.rllib.utils.typing import TensorType
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tf1, tf, tfv = try_import_tf()
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class SkipConnection(tf.keras.layers.Layer if tf else object):
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"""Skip connection layer.
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Adds the original input to the output (regular residual layer) OR uses
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input as hidden state input to a given fan_in_layer.
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"""
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def __init__(self, layer: Any, fan_in_layer: Optional[Any] = None, **kwargs):
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"""Initializes a SkipConnection keras layer object.
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Args:
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layer (tf.keras.layers.Layer): Any layer processing inputs.
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fan_in_layer (Optional[tf.keras.layers.Layer]): An optional
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layer taking two inputs: The original input and the output
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of `layer`.
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"""
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super().__init__(**kwargs)
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self._layer = layer
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self._fan_in_layer = fan_in_layer
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def call(self, inputs: TensorType, **kwargs) -> TensorType:
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# del kwargs
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outputs = self._layer(inputs, **kwargs)
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# Residual case, just add inputs to outputs.
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if self._fan_in_layer is None:
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outputs = outputs + inputs
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# Fan-in e.g. RNN: Call fan-in with `inputs` and `outputs`.
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else:
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# NOTE: In the GRU case, `inputs` is the state input.
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outputs = self._fan_in_layer((inputs, outputs))
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return outputs
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