diff --git a/owlps-positioning/src/inputcsv.cc b/owlps-positioning/src/inputcsv.cc
index e17d5ff..355b993 100644
--- a/owlps-positioning/src/inputcsv.cc
+++ b/owlps-positioning/src/inputcsv.cc
@@ -90,17 +90,8 @@ const Request& InputCSV::get_next_request()
   // Read Mobile MAC field
   if (ti == tok.end()) // Wrong number of fields
     return *current_request ;
-
-  // If the mobile did not exist, we create it
-  try
-    {
-      Stock::get_mobile(*ti) ;
-    }
-  catch (element_not_found e)
-    {
-      Stock::getw_mobile(*ti).set_mac_addr(*ti) ;
-    }
-  current_request->set_mobile(&Stock::get_mobile(*ti)) ;
+  const Mobile &mobile = Stock::find_create_mobile(*ti) ;
+  current_request->set_mobile(&mobile) ;
 
   // Read Timestamp field
   if (++ti == tok.end())
@@ -213,19 +204,8 @@ const Request& InputCSV::get_next_request()
           current_request->clear() ; // Blank current request
           return *current_request ;
         }
-
-      // If the AP did not exist, we create it
-      try
-        {
-          Stock::get_ap(mac_ap) ;
-        }
-      catch (element_not_found e)
-        {
-          Stock::getw_ap(mac_ap).set_mac_addr(mac_ap) ;
-        }
-      measurements[mac_ap].set_ap(&Stock::get_ap(mac_ap)) ;
-
-      // Adding value
+      const AccessPoint &ap = Stock::find_create_ap(mac_ap) ;
+      measurements[mac_ap].set_ap(&ap) ;
       measurements[mac_ap].add_ss(ss) ;
     }
 
diff --git a/owlps-positioning/src/stock.cc b/owlps-positioning/src/stock.cc
index 45566f3..3f14878 100644
--- a/owlps-positioning/src/stock.cc
+++ b/owlps-positioning/src/stock.cc
@@ -44,6 +44,21 @@ const Mobile& Stock::get_mobile(const string &mac)
 }
 
 
+/**
+ * The MAC address of the Mobile is initialised.
+ */
+const Mobile& Stock::find_create_mobile(const string &mac)
+{
+  unordered_map<string, Mobile>::const_iterator i = mobiles.find(mac) ;
+  if (i != mobiles.end())
+    return i->second ;
+
+  Mobile &mobile = mobiles[mac] ;
+  mobile.set_mac_addr(mac) ;
+  return mobile ;
+}
+
+
 /**
  * @param mac The MAC address of the AccessPoint to search for.
  * It must be a valid MAC address, as no check is performed.
@@ -61,6 +76,21 @@ const AccessPoint& Stock::get_ap(const string &mac)
 }
 
 
+/**
+ * The MAC address of the AccessPoint is initialised.
+ */
+const AccessPoint& Stock::find_create_ap(const string &mac)
+{
+  unordered_map<string, AccessPoint>::const_iterator i = aps.find(mac) ;
+  if (i != aps.end())
+    return i->second ;
+
+  AccessPoint &ap = aps[mac] ;
+  ap.set_mac_addr(mac) ;
+  return ap ;
+}
+
+
 const ReferencePoint& Stock::
 find_create_reference_point(const ReferencePoint &point)
 {
diff --git a/owlps-positioning/src/stock.hh b/owlps-positioning/src/stock.hh
index 3c14690..7d0e6fc 100644
--- a/owlps-positioning/src/stock.hh
+++ b/owlps-positioning/src/stock.hh
@@ -28,11 +28,15 @@ private:
 public:
   /// Read the Mobile corresponding to a given MAC address
   static const Mobile& get_mobile(const std::string &mac) ;
+  /// Look for a Mobile and create it if it does not exist
+  static const Mobile& find_create_mobile(const std::string &mac) ;
   /// Get a reference to the Mobile corresponding to a given MAC address
   static Mobile& getw_mobile(const std::string &mac) ;
 
   /// Read the AccessPoint corresponding to a given MAC address
   static const AccessPoint& get_ap(const std::string &mac) ;
+  /// Look for an AccessPoint and create it if it does not exist
+  static const AccessPoint& find_create_ap(const std::string &mac) ;
   /// Get a reference to the AccessPoint corresponding to a given MAC address
   static AccessPoint& getw_ap(const std::string &mac) ;