diff --git a/dvmp/analysis/util.h b/dvmp/analysis/util.h
index 3d4b0a445be2b5b3d2b243b67372fc0747c33b49..dad7048e016d7c5d03cca9eb37481472ea4e5a74 100644
--- a/dvmp/analysis/util.h
+++ b/dvmp/analysis/util.h
@@ -159,28 +159,28 @@ get_y(const std::pair<ROOT::Math::PxPyPzMVector, ROOT::Math::PxPyPzMVector>&
 //========================================================================================================
 //for structure functions
 
-struct structure_func{    //add more when needed
+struct inv_quant{    //add more when needed
     double nu, Q2, x;
 };
 
 //for simu
-inline structure_func calc_structure_func_simu(const std::vector<ROOT::Math::PxPyPzMVector>& parts){
+inline inv_quant calc_inv_quant_simu(const std::vector<ROOT::Math::PxPyPzMVector>& parts){
   ROOT::Math::PxPyPzMVector q(parts[0] - parts[2]);
   ROOT::Math::PxPyPzMVector P(parts[3]);
   
   double nu = q.Dot(P) / P.mass();
   double Q2 = - q.Dot(q);  
-  structure_func quantities = {nu, Q2, Q2/2./P.mass()/nu};
+  inv_quant quantities = {nu, Q2, Q2/2./P.mass()/nu};
   return quantities;
 }
 
-inline double get_nu_simu(structure_func quantities) {
+inline double get_nu_simu(inv_quant quantities) {
   return quantities.nu/1000.;
 }
-inline double get_Q2_simu(structure_func quantities) {
+inline double get_Q2_simu(inv_quant quantities) {
   return quantities.Q2;
 }
-inline double get_x_simu(structure_func quantities) {
+inline double get_x_simu(inv_quant quantities) {
   return quantities.x;
 }
 
diff --git a/dvmp/analysis/vm_invar.cxx b/dvmp/analysis/vm_invar.cxx
index 438959903582f5505067621a6580424e990539de..99b85ef0ce17140c646b6f82ad23308812efcb0a 100644
--- a/dvmp/analysis/vm_invar.cxx
+++ b/dvmp/analysis/vm_invar.cxx
@@ -83,10 +83,10 @@ int vm_invar(const std::string& config_name) {
           .Define("N", "p_rec.size()")
           .Define("p_sim", util::momenta_from_simulation, {"mcparticles2"})
           //================================================================
-          .Define("structure_functions", util::calc_structure_func_simu, {"p_sim"})
-          .Define("nu_sim" , util::get_nu_simu, {"structure_functions"})
-          .Define("Q2_sim" , util::get_Q2_simu, {"structure_functions"})
-          .Define("x_sim" ,  util::get_x_simu, {"structure_functions"});
+          .Define("invariant_quantities", util::calc_inv_quant_simu, {"p_sim"})
+          .Define("nu_sim" , util::get_nu_simu, {"invariant_quantities"})
+          .Define("Q2_sim" , util::get_Q2_simu, {"invariant_quantities"})
+          .Define("x_sim" ,  util::get_x_simu, {"invariant_quantities"});
           //================================================================
 
   // Define output histograms