magail4autodrive: first commit

Algorithm/policy.py

@@ -0,0 +1,31 @@
+import torch
+import numpy as np
+from torch import nn
+from .utils import build_mlp, reparameterize, evaluate_lop_pi
+
+class StateIndependentPolicy(nn.Module):
+
+    def __init__(self, state_shape, action_shape, hidden_units=(64, 64),
+                 hidden_activation=nn.Tanh()):
+        super().__init__()
+
+        self.net = build_mlp(
+            input_dim=state_shape[0],
+            output_dim=action_shape[0],
+            hidden_units=hidden_units,
+            hidden_activation=hidden_activation
+        )
+        self.log_stds = nn.Parameter(torch.zeros(1, action_shape[0]))
+        self.means = None
+
+    def forward(self, states):
+        return torch.tanh(self.net(states))
+
+    def sample(self, states):
+        self.means = self.net(states)
+        actions, log_pis = reparameterize(self.means, self.log_stds)
+        return actions, log_pis
+
+    def evaluate_log_pi(self, states, actions):
+        self.means = self.net(states)
+        return evaluate_lop_pi(self.means, self.log_stds, actions)