diff --git a/Src/GroupTree/Core/FGroupLinearTree.hpp b/Src/GroupTree/Core/FGroupLinearTree.hpp
index ec5f9d6d80d047a5043b50cbdacaddaa33a71635..e6119cf6901e8fe2f89d148f7d88d10253e6c89f 100644
--- a/Src/GroupTree/Core/FGroupLinearTree.hpp
+++ b/Src/GroupTree/Core/FGroupLinearTree.hpp
@@ -21,7 +21,7 @@ protected:
 
     std::vector<node_t>* linear_tree;
     std::vector<std::pair<unsigned long long int,unsigned long long int>> particle_repartition;
-    bool unknow_particle_repartition = true:;
+    bool unknow_particle_repartition = true;
 
 public:
 
@@ -179,14 +179,18 @@ public:
         return this->get_leaf_level();
     }
 
-    size_t get_first_morton_index(){
+    size_t get_first_morton_index() const{
         return this->linear_tree->front().morton_index;
     }
 
-    size_t get_last_morton_index(){
+    size_t get_last_morton_index() const{
         return this->linear_tree->back().morton_index;
     }
 
+    /**
+     * This function print the information of this current class
+     * @author benjamin.dufoyer@inria.fr
+     */
     void print_info_tree(){
         std::cout << " nb_leaf : " << this->linear_tree->size() << std::endl;
         std::cout << " nb_block : " << nb_block << std::endl;
@@ -196,6 +200,10 @@ public:
         }
     }
 
+    /**
+     * This function return the linear tree associated with this calss
+     * @author benjamin.dufoyer@inria.fr
+     */
     std::vector<node_t>* get_tree(){
         return this->linear_tree;
     }
@@ -210,6 +218,7 @@ public:
     void set_particle_repartition(
         std::vector<particle_t> particle_container)
     {
+        unknow_particle_repartition = false;
        dstr_grp_tree_builder::know_particle_division(
            this->mpi_conf,
            particle_container,
@@ -217,7 +226,7 @@ public:
     }
 
     std::vector<std::pair<unsigned long long int,unsigned long long int>>*
-    get_particle_repartition()
+    get_particle_repartition(){
         // TO get the particle repartition, you will compute it before
         FAssert(!unknow_particle_repartition);
         return &this->particle_repartition;
@@ -233,15 +242,17 @@ public:
     /**
      * return the max morton index of the left proc
      * it's needed for the distributed construction of the groupTree
-     * you will compute the repartition before calling this function
+     * [RESTRICTION] you will compute the repartition before calling this function
      * @author benjamin.dufoyer@inria.fr
-     * @return Morton Index
+     * @return max left morton index, -1 if he doesn't exist
      */
-    unsigned long long int get_left_limit(){
+    long long int get_left_limit(){
+        // Check if the repartition have been compute
         FAssert(!unknow_particle_repartition);
         int my_rank = this->mpi_conf.comm.rank();
+        long long int left_limit = -1;
         if(my_rank != 0){
-            left_limit = this->particle_repartition[my_rank-1].second;
+            left_limit = (long long int )this->particle_repartition[my_rank-1].second;
         }
         return left_limit;
     }
@@ -316,6 +327,19 @@ public:
 
         }
 
+        /**
+         * This function is used to show the FGroupLinearTee more easly
+         * @author benjamin.dufoyer@inria.fr
+         */
+        friend
+        std::ostream& operator<<(std::ostream& os, const FGroupLinearTree& n) {
+        return os << "--> Number of leaf : " << n.get_nb_leaf()
+                  << "\n first leaf : "      << n.get_first_morton_index()
+                  << "\n last  leaf : "      << n.get_last_morton_index()
+                  << "\n block_size "          << n.get_block_size()
+                  << "\n number of block : "   << n.get_nb_block();
+        }
+
 
 };