From aec332ff0cbfb1a5adcb887c079fb120edbe96de Mon Sep 17 00:00:00 2001
From: ottofabian <fabi.otto@t-online.de>
Date: Mon, 31 Aug 2020 10:33:11 +0200
Subject: [PATCH] fixed some issues with SimpleReacher state space

---
 alr_envs/classic_control/simple_reacher.py | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/alr_envs/classic_control/simple_reacher.py b/alr_envs/classic_control/simple_reacher.py
index 42fe93a..945bc3e 100644
--- a/alr_envs/classic_control/simple_reacher.py
+++ b/alr_envs/classic_control/simple_reacher.py
@@ -8,7 +8,7 @@ from gym.utils import seeding
 import matplotlib as mpl
 import matplotlib.pyplot as plt
 
-if not os.environ.get("DISPLAY", None):
+if os.environ.get("DISPLAY", None):
     mpl.use('Qt5Agg')
 
 
@@ -27,7 +27,7 @@ class SimpleReacherEnv(gym.Env, utils.EzPickle):
 
         self._goal_pos = None
 
-        self.joints = None
+        self._joints = None
         self._joint_angle = None
         self._angle_velocity = None
 
@@ -37,7 +37,7 @@ class SimpleReacherEnv(gym.Env, utils.EzPickle):
         state_bound = np.hstack([
             [np.pi] * self.n_links,
             [np.inf] * self.n_links,
-            [np.inf],
+            [np.inf] * 2,  # x-y coordinates of target distance
             [np.inf]  # TODO: Maybe
         ])
         self.action_space = spaces.Box(low=-action_bound, high=action_bound, shape=action_bound.shape)
@@ -87,13 +87,13 @@ class SimpleReacherEnv(gym.Env, utils.EzPickle):
 
     def _update_joints(self):
         """
-        update joints to get new end effector position. The other links are only required for rendering.
+        update _joints to get new end effector position. The other links are only required for rendering.
         Returns:
 
         """
         angles = np.cumsum(self._joint_angle)
         x = self.link_lengths * np.vstack([np.cos(angles), np.sin(angles)])
-        self.joints[1:] = self.joints[0] + np.cumsum(x.T, axis=0)
+        self._joints[1:] = self._joints[0] + np.cumsum(x.T, axis=0)
 
     def _get_reward(self, action):
         diff = self.end_effector - self._goal_pos
@@ -113,14 +113,14 @@ class SimpleReacherEnv(gym.Env, utils.EzPickle):
         # Sample only orientation of first link, i.e. the arm is always straight.
         self._joint_angle = np.hstack([[self.np_random.uniform(-np.pi, np.pi)], np.zeros(self.n_links - 1)])
         self._angle_velocity = np.zeros(self.n_links)
-        self.joints = np.zeros((self.n_links + 1, 2))
+        self._joints = np.zeros((self.n_links + 1, 2))
         self._update_joints()
 
         self._goal_pos = self._get_random_goal()
         return self._get_obs().copy()
 
     def _get_random_goal(self):
-        center = self.joints[0]
+        center = self._joints[0]
 
         # Sample uniformly in circle with radius R around center of reacher.
         R = np.sum(self.link_lengths)
@@ -143,7 +143,7 @@ class SimpleReacherEnv(gym.Env, utils.EzPickle):
         plt.cla()
 
         # Arm
-        plt.plot(self.joints[:, 0], self.joints[:, 1], 'ro-', markerfacecolor='k')
+        plt.plot(self._joints[:, 0], self._joints[:, 1], 'ro-', markerfacecolor='k')
 
         # goal
         goal_pos = self._goal_pos.T
@@ -162,7 +162,7 @@ class SimpleReacherEnv(gym.Env, utils.EzPickle):
 
     @property
     def end_effector(self):
-        return self.joints[self.n_links].T
+        return self._joints[self.n_links].T
 
 
 def angle_normalize(x):