Added balancing reacher task and stochastic search task interface

alr_envs/utils/utils.py

@@ -0,0 +1,20 @@
+import numpy as np
+
+
+def angle_normalize(x, type="deg"):
+    """
+    normalize angle x to [-pi,pi].
+    Args:
+        x: Angle in either degrees or radians
+        type: one of "deg" or "rad" for x being in degrees or radians
+
+    Returns:
+
+    """
+    if type == "deg":
+        return ((x + np.pi) % (2 * np.pi)) - np.pi
+    elif type == "rad":
+        two_pi = 2 * np.pi
+        return x - two_pi * np.floor((x + np.pi) / two_pi)
+    else:
+        raise ValueError(f"Invalid type {type}. Choose on of 'deg' or 'rad'.")