diff --git a/poisson/discrete/discrete_poisson.py b/poisson/discrete/discrete_poisson.py
index 3be65a075b6dc5608557fb92460844414f188df2..f4069a369582b26ffd90063fda23c0c0add7703b 100644
--- a/poisson/discrete/discrete_poisson.py
+++ b/poisson/discrete/discrete_poisson.py
@@ -133,20 +133,20 @@ def assemble_points_system(region_ndtuple, surface_points, region_name,
         region_ndtuple.index_of_closed_points = np.hstack(
             closed_region_points[region_name])
     else:
-        region_ndtuple.index_of_closed_points = np.array([])
+        region_ndtuple.index_of_closed_points = np.array([], dtype=int)
 
     surface_point_region = []
     for sub_region_name in sub_region_names[region_name]:
         if sub_region_name in surface_points.keys():
             surface_point_region.append(surface_points[sub_region_name])
 
-    if len(surface_point_region) >0:
+    if len(surface_point_region) > 0:
 
         surface_point_region = np.hstack(surface_point_region)
 
         region_ndtuple.index_of_system_points = np.intersect1d(
                 surface_point_region,
-                region_ndtuple.index_of_closed_points )
+                region_ndtuple.index_of_closed_points)
     else:
         region_ndtuple.index_of_system_points = \
             region_ndtuple.index_of_closed_points
@@ -192,7 +192,8 @@ def create_regions_nmtp(regions_point, regions_properties,
             region_ndtuple[region_name].index_of_mesh_points = np.hstack(
                 list(region_point_dict.values()))
         else:
-            region_ndtuple[region_name].index_of_mesh_points = np.array([])
+            region_ndtuple[region_name].index_of_mesh_points = np.array(
+                [], dtype=int)
 
         # Depends on the type of mesh used.
         # There is no real need to return anything as reguin_ndtuple is