diff --git a/main_package/classes/estimators/structure_score_based_estimator.py b/main_package/classes/estimators/structure_score_based_estimator.py
index 9c9ceec..63e6d90 100644
--- a/main_package/classes/estimators/structure_score_based_estimator.py
+++ b/main_package/classes/estimators/structure_score_based_estimator.py
@@ -51,7 +51,7 @@ class StructureScoreBasedEstimator(se.StructureEstimator):
 
     @timing
     def estimate_structure(self, max_parents:int = None, iterations_number:int= 40,
-                         patience:int = None, tabu_length:int = None, tabu_rules_duration:int = 5,
+                         patience:int = None, tabu_length:int = None, tabu_rules_duration:int = None,
                          optimizer: str = 'hill' ):
         """
         Compute the score-based algorithm to find the optimal structure
diff --git a/main_package/classes/optimizers/tabu_search.py b/main_package/classes/optimizers/tabu_search.py
index fdce6a2..04aa5ae 100644
--- a/main_package/classes/optimizers/tabu_search.py
+++ b/main_package/classes/optimizers/tabu_search.py
@@ -31,8 +31,8 @@ class TabuSearch(Optimizer):
                 max_parents:int = None,
                 iterations_number:int= 40,
                 patience:int = None,
-                tabu_length:int = 0,
-                tabu_rules_duration = 5
+                tabu_length:int = None,
+                tabu_rules_duration = None
                 ):
         """
         Compute Optimization process for a structure_estimator
@@ -71,6 +71,14 @@ class TabuSearch(Optimizer):
         other_nodes =  set([node for node in self.structure_estimator.sample_path.structure.nodes_labels if node != self.node_id])
         actual_best_score = self.structure_estimator.get_score_from_graph(graph,self.node_id)
 
+
+        'initialize tabu_length and tabu_rules_duration if None'
+        if self.tabu_length is None:
+            self.tabu_length = len(other_nodes)
+
+        if self.tabu_rules_duration is None:
+            self.tabu_tabu_rules_durationength = len(other_nodes)
+
         tabu_set = set()
         tabu_queue = queue.Queue()
 
diff --git a/main_package/tests/optimizers/test_tabu_search.py b/main_package/tests/optimizers/test_tabu_search.py
index 4deb126..87ed6f4 100644
--- a/main_package/tests/optimizers/test_tabu_search.py
+++ b/main_package/tests/optimizers/test_tabu_search.py
@@ -37,7 +37,7 @@ class TestTabuSearch(unittest.TestCase):
         se1 = se.StructureScoreBasedEstimator(self.s1)
         edges = se1.estimate_structure(
                             max_parents = None,
-                            iterations_number = 100,
+                            iterations_number = 40,
                             patience = None,
                             tabu_length = 15,
                             tabu_rules_duration = 15,