PI control problem

class_model/include/class_model/follower.h

@@ -40,6 +40,7 @@ public:
     int find_ref_drone(global_location** data, size_t index, int leaderID);
 
     float lon[3],lat[3];
+    global_location vector_LT,vector_SM;
     
 
 private:

class_model/src/follower.cpp

@@ -127,11 +127,13 @@ void FollowerClass::plane(global_location* target, global_location* leader, glob
 
 int FollowerClass::direct(global_location* target, global_location* leader, DroneStatus self, DroneStatus member){
 
-    global_location vector_LT,vector_SM;
     float m,n,k,cosTheta;
 
+    if(flag == 0){
     vector_LT.lon = target->lon - leader->lon;       //vector_LT (leader->target)     
     vector_LT.lat = target->lat - leader->lat;
+    flag = 1;
+    }
     vector_SM.lon = member.init_location.lon - self.init_location.lon;       //vector_SM (self->member)
     vector_SM.lat = member.init_location.lat - self.init_location.lat;
     k = (vector_LT.lon*vector_SM.lon)+(vector_LT.lat*vector_SM.lat);     //k = vector_LT dot vector_SM