local param gird (#94)

local param gird. Fixes #96

surprise/evaluate.py

@@ -178,7 +178,7 @@ def __init__(self, algo_class, param_grid, measures=['rmse', 'mae'],
         self.best_estimator = CaseInsensitiveDefaultDict(list)
         self.cv_results = defaultdict(list)
         self.algo_class = algo_class
-        self.param_grid = param_grid
+        self.param_grid = param_grid.copy()
         self.measures = [measure.upper() for measure in measures]
         self.n_jobs = n_jobs
         self.pre_dispatch = pre_dispatch
@@ -187,20 +187,20 @@ def __init__(self, algo_class, param_grid, measures=['rmse', 'mae'],
 
         # As sim_options and bsl_options are dictionaries, they require a
         # special treatment.
-        if 'sim_options' in param_grid:
-            sim_options = param_grid['sim_options']
+        if 'sim_options' in self.param_grid:
+            sim_options = self.param_grid['sim_options']
             sim_options_list = [dict(zip(sim_options, v)) for v in
                                 product(*sim_options.values())]
-            param_grid['sim_options'] = sim_options_list
+            self.param_grid['sim_options'] = sim_options_list
 
-        if 'bsl_options' in param_grid:
-            bsl_options = param_grid['bsl_options']
+        if 'bsl_options' in self.param_grid:
+            bsl_options = self.param_grid['bsl_options']
             bsl_options_list = [dict(zip(bsl_options, v)) for v in
                                 product(*bsl_options.values())]
-            param_grid['bsl_options'] = bsl_options_list
+            self.param_grid['bsl_options'] = bsl_options_list
 
-        self.param_combinations = [dict(zip(param_grid, v)) for v in
-                                   product(*param_grid.values())]
+        self.param_combinations = [dict(zip(self.param_grid, v)) for v in
+                                   product(*self.param_grid.values())]
 
     def evaluate(self, data):
         """Runs the grid search on dataset.