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https://github.com/vale981/ray
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d15609ba2a
This PR implements a PyTorch version of RLlib's ARS algorithm using RLlib's functional algo builder API. It also adds a regression test for ARS (torch) on CartPole.
100 lines
3.7 KiB
Python
100 lines
3.7 KiB
Python
import logging
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import numpy as np
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from ray.rllib.models.torch.torch_modelv2 import TorchModelV2
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from ray.rllib.models.torch.misc import SlimFC, normc_initializer
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from ray.rllib.utils.annotations import override
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from ray.rllib.utils.framework import get_activation_fn
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from ray.rllib.utils import try_import_torch
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_, nn = try_import_torch()
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logger = logging.getLogger(__name__)
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class FullyConnectedNetwork(TorchModelV2, nn.Module):
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"""Generic fully connected network."""
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def __init__(self, obs_space, action_space, num_outputs, model_config,
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name):
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TorchModelV2.__init__(self, obs_space, action_space, num_outputs,
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model_config, name)
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nn.Module.__init__(self)
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activation = get_activation_fn(
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model_config.get("fcnet_activation"), framework="torch")
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hiddens = model_config.get("fcnet_hiddens")
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no_final_linear = model_config.get("no_final_linear")
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# TODO(sven): implement case: vf_shared_layers = False.
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# vf_share_layers = model_config.get("vf_share_layers")
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logger.debug("Constructing fcnet {} {}".format(hiddens, activation))
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layers = []
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prev_layer_size = int(np.product(obs_space.shape))
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self._logits = None
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# Create layers 0 to second-last.
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for size in hiddens[:-1]:
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layers.append(
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SlimFC(
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in_size=prev_layer_size,
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out_size=size,
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initializer=normc_initializer(1.0),
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activation_fn=activation))
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prev_layer_size = size
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# The last layer is adjusted to be of size num_outputs, but it's a
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# layer with activation.
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if no_final_linear and self.num_outputs:
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layers.append(
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SlimFC(
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in_size=prev_layer_size,
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out_size=self.num_outputs,
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initializer=normc_initializer(1.0),
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activation_fn=activation))
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prev_layer_size = self.num_outputs
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# Finish the layers with the provided sizes (`hiddens`), plus -
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# iff num_outputs > 0 - a last linear layer of size num_outputs.
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else:
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if len(hiddens) > 0:
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layers.append(
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SlimFC(
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in_size=prev_layer_size,
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out_size=hiddens[-1],
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initializer=normc_initializer(1.0),
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activation_fn=activation))
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prev_layer_size = hiddens[-1]
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if self.num_outputs:
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self._logits = SlimFC(
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in_size=prev_layer_size,
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out_size=self.num_outputs,
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initializer=normc_initializer(0.01),
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activation_fn=None)
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else:
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self.num_outputs = (
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[np.product(obs_space.shape)] + hiddens[-1:-1])[-1]
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self._hidden_layers = nn.Sequential(*layers)
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# TODO(sven): Implement non-shared value branch.
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self._value_branch = SlimFC(
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in_size=prev_layer_size,
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out_size=1,
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initializer=normc_initializer(1.0),
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activation_fn=None)
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# Holds the current value output.
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self._cur_value = None
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@override(TorchModelV2)
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def forward(self, input_dict, state, seq_lens):
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obs = input_dict["obs_flat"]
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features = self._hidden_layers(obs.reshape(obs.shape[0], -1))
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logits = self._logits(features) if self._logits else features
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self._cur_value = self._value_branch(features).squeeze(1)
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return logits, state
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@override(TorchModelV2)
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def value_function(self):
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assert self._cur_value is not None, "must call forward() first"
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return self._cur_value
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