Continuous A3C

utils/shifter.py

@@ -0,0 +1,28 @@
+# Adapted from https://github.com/kvfrans/parallel-trpo/blob/master/utils.py
+class Shifter:
+    def __init__(self, filter_mean=True):
+        self.m = 0
+        self.v = 0
+        self.n = 0.
+        self.filter_mean = filter_mean
+
+    def state_dict(self):
+        return {'m': self.m,
+                'v': self.v,
+                'n': self.n}
+
+    def load_state_dict(self, saved):
+        self.m = saved['m']
+        self.v = saved['v']
+        self.n = saved['n']
+
+    def __call__(self, o):
+        self.m = self.m * (self.n / (self.n + 1)) + o * 1 / (1 + self.n)
+        self.v = self.v * (self.n / (self.n + 1)) + (o - self.m) ** 2 * 1 / (1 + self.n)
+        self.std = (self.v + 1e-6) ** .5  # std
+        self.n += 1
+        if self.filter_mean:
+            o_ = (o - self.m) / self.std
+        else:
+            o_ = o / self.std
+        return o_