Corrected BanditScheduler ask method

ribs/schedulers/_bandit_scheduler.py

@@ -244,13 +244,14 @@ def ask(self):
             reselect = self._active_arr.copy()
 
         # If not enough emitters are active, activate the first num_active.
-        num_needed = self._num_active - self._active_arr.sum()
+        # This always happens on the first iteration(s).
+        nb_activated = self._num_active - self._active_arr.sum()
         i = 0
-        while num_needed > 0:
+        while nb_activated > 0:
             reselect[i] = False
             if not self._active_arr[i]:
                 self._active_arr[i] = True
-                num_needed -= 1
+                nb_activated -= 1
             i += 1
 
         # Deactivate emitters to be reselected.
@@ -273,19 +274,14 @@ def ask(self):
                     self._zeta * np.sqrt(
                         np.log(self._success.sum()) /
                         self._selection[update_ucb]))
-            # Activate top emitters based on UCB1.
-            activate = np.argsort(ucb1)[-reselect.sum():]
-            self._active_arr[activate] = True
-
-            # Deactivate emitters if there are too many active emitters.
-            nb_deactivate = self.emitters.sum() - self._num_active
-            deactivate = np.argsort(ucb1)
-            for i in deactivate:
-                if nb_deactivate == 0:
+            # Activate top emitters based on UCB1, until there are num_active
+            # active emitters. Activate only inactive emitters.
+            activate = np.argsort(ucb1)[::-1]
+            for i in activate:
+                if self._active_arr.sum() == self._num_active:
                     break
-                if self._active_arr[i]:
-                    self._active_arr[i] = False
-                    nb_deactivate -= 1
+                if not self._active_arr[i]:
+                    self._active_arr[i] = True
 
         self._cur_solutions = []