add random and weighted random rollout options (fix #65)

src/decmcts.py

@@ -10,6 +10,7 @@ import numpy as np
 import pickle
 import copy
 import warnings
+import random
 
 
 home = [0, -pi/2, pi/4, -pi/4, -pi/2, -pi/4]
@@ -39,11 +40,22 @@ def joint_diff(js1,js2):
     return sum([(j1-j2)**2 for j1,j2 in zip(js1,js2)])
 
 
-def sim_select(data, options, sim_state):
-    j  = sim_state[-1].positions[-1]
-    costs = [joint_diff(j,o.positions[0]) for o in options]
-    return options[np.argmin(costs)] # greedy
-#    return np.random.choice(options) # Random (much slower for some reason)
+def sim_select(data, options, sim_state, method='greedy'):
+    """
+    How to select option during simulation
+    """
+    if method == 'greedy':
+        j  = sim_state[-1].positions[-1]
+        costs = [joint_diff(j,o.positions[0]) for o in options]
+        return options[np.argmin(costs)]
+    elif method == 'random':
+        return random.choice(options)
+    elif method == 'weighted':
+        j  = sim_state[-1].positions[-1]
+        weights = [1/joint_diff(j,o.positions[0]) for o in options]
+        return random.choices(options, weights=weights)[0]
+    else:
+        print("ERROR: Invalid sim_select method: '{}'".format(method))
 
 
 class CombinedSchedule: