From d4ef5c5993c65257ded867406d552fd9aa1b061c Mon Sep 17 00:00:00 2001
From: cathrinS <38454060+cathrinS@users.noreply.github.com>
Date: Thu, 28 Jan 2021 12:07:00 +0100
Subject: [PATCH] [RLlib] Atari-RAM-Preprocessing, unsigned observation vector
 results in a false preprocessed observation (#13013)

---
 rllib/models/preprocessors.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/rllib/models/preprocessors.py b/rllib/models/preprocessors.py
index 44312a807..0abfb8658 100644
--- a/rllib/models/preprocessors.py
+++ b/rllib/models/preprocessors.py
@@ -140,7 +140,7 @@ class AtariRamPreprocessor(Preprocessor):
     @override(Preprocessor)
     def transform(self, observation: TensorType) -> np.ndarray:
         self.check_shape(observation)
-        return (observation - 128) / 128
+        return (observation.astype("float32") - 128) / 128
 
 
 class OneHotPreprocessor(Preprocessor):