fix bug in smac search space convert (#940)

* fix bug in smac search space convert

* update docstring

src/sdk/pynni/nni/smac_tuner/smac_tuner.py

@@ -192,17 +192,20 @@ def convert_loguniform_categorical(self, challenger_dict):
         Returns
         -------
         dict
-            challenger dict
+            dict which stores copy of challengers
         """
+        converted_dict = {}
         for key, value in challenger_dict.items():
             # convert to loguniform
             if key in self.loguniform_key:
-                challenger_dict[key] = np.exp(challenger_dict[key])
+                converted_dict[key] = np.exp(challenger_dict[key])
             # convert categorical back to original value
-            if key in self.categorical_dict:
+            elif key in self.categorical_dict:
                 idx = challenger_dict[key]
-                challenger_dict[key] = self.categorical_dict[key][idx]
-        return challenger_dict
+                converted_dict[key] = self.categorical_dict[key][idx]
+            else:
+                converted_dict[key] = value
+        return converted_dict
 
     def generate_parameters(self, parameter_id):
         """generate one instance of hyperparameters
@@ -220,13 +223,11 @@ def generate_parameters(self, parameter_id):
         if self.first_one:
             init_challenger = self.smbo_solver.nni_smac_start()
             self.total_data[parameter_id] = init_challenger
-            json_tricks.dumps(init_challenger.get_dictionary())
             return self.convert_loguniform_categorical(init_challenger.get_dictionary())
         else:
             challengers = self.smbo_solver.nni_smac_request_challengers()
             for challenger in challengers:
                 self.total_data[parameter_id] = challenger
-                json_tricks.dumps(challenger.get_dictionary())
                 return self.convert_loguniform_categorical(challenger.get_dictionary())
 
     def generate_multiple_parameters(self, parameter_id_list):
@@ -247,7 +248,6 @@ def generate_multiple_parameters(self, parameter_id_list):
             for one_id in parameter_id_list:
                 init_challenger = self.smbo_solver.nni_smac_start()
                 self.total_data[one_id] = init_challenger
-                json_tricks.dumps(init_challenger.get_dictionary())
                 params.append(self.convert_loguniform_categorical(init_challenger.get_dictionary()))
         else:
             challengers = self.smbo_solver.nni_smac_request_challengers()
@@ -257,7 +257,6 @@ def generate_multiple_parameters(self, parameter_id_list):
                 if cnt >= len(parameter_id_list):
                     break
                 self.total_data[parameter_id_list[cnt]] = challenger
-                json_tricks.dumps(challenger.get_dictionary())
                 params.append(self.convert_loguniform_categorical(challenger.get_dictionary()))
                 cnt += 1
         return params