diff --git a/src/nt_composition/config.py b/src/nt_composition/config.py
index ace3744b14cff356a8a0ca6742bcfb1b90f710cc..14f0a395501be622c4175fc7c9c0a990fbd78ba0 100644
--- a/src/nt_composition/config.py
+++ b/src/nt_composition/config.py
@@ -10,11 +10,25 @@ file that will be produced by this module.
 from ..db_utils.config import Config
 
 
-def get_density_file(project: str, ft_type: str, ft: str,
+def get_weight_folder(weight: int):
+    """
+    Get the weight folder.
+
+    :param weight: The weight of interaction to consider
+    :return: The folder that will contains the interaction with a weight \
+    greater or equal to `weigh` in ChIA-PET projects
+    """
+    weight_folder = ConfigNt.density_folder / f"weight:{weight}"
+    weight_folder.mkdir(parents=True, exist_ok=True)
+    return weight_folder
+
+
+def get_density_file(weight: int, project: str, ft_type: str, ft: str,
                      fig: bool = False):
     """
     Get the filename that will contain the density data or figure.
 
+    :param weight: The weight of interaction to consider
     :param project: A project name
     :param ft_type: A feature type
     :param ft: A feature
@@ -25,15 +39,16 @@ def get_density_file(project: str, ft_type: str, ft: str,
         ext = "pdf"
     else:
         ext = "txt"
-    res_folder = ConfigNt.density_folder / project
+    res_folder = get_weight_folder(weight) / project
     res_folder.mkdir(exist_ok=True, parents=True)
     return res_folder / f"{project}_{ft_type}_{ft}_density.{ext}"
 
 
-def get_density_recap(ft_type: str, ft: str, fig: bool = False):
+def get_density_recap(weight: int, ft_type: str, ft: str, fig: bool = False):
     """
     Get the density correlation recap file.
 
+    :param weight: The weight of interaction to consider
     :param ft_type:  A feature type
     :param ft:  A feature
     :return:
@@ -42,8 +57,21 @@ def get_density_recap(ft_type: str, ft: str, fig: bool = False):
         ext = "pdf"
     else:
         ext = "txt"
-    ConfigNt.density_folder.mkdir(exist_ok=True, parents=True)
-    return ConfigNt.density_folder / f"{ft_type}_{ft}_density_recap.{ext}"
+    outfolder = get_weight_folder(weight)
+    outfolder.mkdir(exist_ok=True, parents=True)
+    return outfolder / f"{ft_type}_{ft}_density_recap.{ext}"
+
+
+def get_interaction_file(weight: int):
+    """
+    Return the interaction file : coresponding to the file containing \
+    iteraction with a weight greater or eaqual to `weight`
+
+    :param weight: minimum weight of interaction to \
+    concider
+    :return: The interaction filename
+    """
+    return ConfigNt.interaction / f"interaction_number_weight>={weight}_by_project.txt"
 
 
 class ConfigNt:
@@ -56,7 +84,7 @@ class ConfigNt:
     db_file = Config.db_file
     output_folder = result / "nt_composition"
     interaction = output_folder / 'interaction_number'
-    interaction_file = interaction / "interaction_number_by_project.txt"
+    get_interaction_file = get_interaction_file
     density_folder = output_folder / 'density_fig'
     get_density_recap = get_density_recap
     selected_project = interaction / "selected_sample.txt"