[tune] Save/Restore for Suggestion Algs (#5719)

python/ray/tune/suggest/nevergrad.py

@@ -3,6 +3,7 @@ from __future__ import division
 from __future__ import print_function
 
 import logging
+import pickle
 try:
     import nevergrad as ng
 except ImportError:
@@ -145,3 +146,14 @@ class NevergradSearch(SuggestionAlgorithm):
 
     def _num_live_trials(self):
         return len(self._live_trial_mapping)
+
+    def save(self, checkpoint_dir):
+        trials_object = (self._nevergrad_opt, self._parameters)
+        with open(checkpoint_dir, "wb") as outputFile:
+            pickle.dump(trials_object, outputFile)
+
+    def restore(self, checkpoint_dir):
+        with open(checkpoint_dir, "rb") as inputFile:
+            trials_object = pickle.load(inputFile)
+        self._nevergrad_opt = trials_object[0]
+        self._parameters = trials_object[1]