diff --git a/include/Helmholtz.h b/include/Helmholtz.h
index 124ba32a..10c81572 100644
--- a/include/Helmholtz.h
+++ b/include/Helmholtz.h
@@ -377,16 +377,18 @@ public:
 
     void to_json(rapidjson::Value &el, rapidjson::Document &doc);
 
-    long double base(const long double &tau, const long double &delta) throw();
-    long double dDelta(const long double &tau, const long double &delta) throw();
-    long double dTau(const long double &tau, const long double &delta) throw();
-    long double dDelta2(const long double &tau, const long double &delta) throw();
-    long double dDelta_dTau(const long double &tau, const long double &delta) throw();
-    long double dTau2(const long double &tau, const long double &delta) throw();
-    long double dDelta3(const long double &tau, const long double &delta) throw();
-    long double dDelta2_dTau(const long double &tau, const long double &delta) throw();
-    long double dDelta_dTau2(const long double &tau, const long double &delta) throw();
-    long double dTau3(const long double &tau, const long double &delta) throw();
+    long double base(const long double &tau, const long double &delta) throw(){Derivatives deriv; all(tau,delta,deriv); return deriv.alphar;};
+    long double dDelta(const long double &tau, const long double &delta) throw(){Derivatives deriv; all(tau,delta,deriv); return deriv.dalphar_ddelta;};
+    long double dTau(const long double &tau, const long double &delta) throw(){Derivatives deriv; all(tau,delta,deriv); return deriv.dalphar_dtau;};
+    long double dDelta2(const long double &tau, const long double &delta) throw(){Derivatives deriv; all(tau,delta,deriv); return deriv.d2alphar_ddelta2;};
+    long double dDelta_dTau(const long double &tau, const long double &delta) throw(){Derivatives deriv; all(tau,delta,deriv); return deriv.d2alphar_ddelta_dtau;};
+    long double dTau2(const long double &tau, const long double &delta) throw(){Derivatives deriv; all(tau,delta,deriv); return deriv.d2alphar_dtau2;};
+    long double dDelta3(const long double &tau, const long double &delta) throw(){Derivatives deriv; all(tau,delta,deriv); return deriv.d3alphar_ddelta3;};
+    long double dDelta2_dTau(const long double &tau, const long double &delta) throw(){Derivatives deriv; all(tau,delta,deriv); return deriv.d3alphar_ddelta2_dtau;};
+    long double dDelta_dTau2(const long double &tau, const long double &delta) throw(){Derivatives deriv; all(tau,delta,deriv); return deriv.d3alphar_ddelta_dtau2;};
+    long double dTau3(const long double &tau, const long double &delta) throw(){Derivatives deriv; all(tau,delta,deriv); return deriv.d3alphar_dtau3;};
+    
+    void all(const long double &tau, const long double &delta, Derivatives &deriv) throw();
 };
 
 class ResidualHelmholtzContainer
diff --git a/src/Helmholtz.cpp b/src/Helmholtz.cpp
index 8ccaa3ad..edfc6b29 100644
--- a/src/Helmholtz.cpp
+++ b/src/Helmholtz.cpp
@@ -721,90 +721,32 @@ long double ResidualHelmholtzSAFTAssociating::d3g_deta3(const long double &eta)
 long double ResidualHelmholtzSAFTAssociating::eta(const long double &delta){
     return this->vbarn*delta;
 }
-long double ResidualHelmholtzSAFTAssociating::base(const long double &tau, const long double &delta) throw()
-{
-    if (disabled){return 0;}
-    long double X = this->X(delta, this->Deltabar(tau, delta));
-    return this->m*this->a*((log(X)-X/2.0+0.5));
-}
-long double ResidualHelmholtzSAFTAssociating::dDelta(const long double &tau, const long double &delta) throw()
-{
-    if (disabled){return 0;}
-    long double X = this->X(delta, this->Deltabar(tau, delta));
-    return this->m*this->a*(1/X-0.5)*this->dX_ddelta(tau, delta);
-}
-long double ResidualHelmholtzSAFTAssociating::dTau(const long double &tau, const long double &delta) throw()
-{
-    if (disabled){return 0;}
-    long double X = this->X(delta, this->Deltabar(tau, delta));
-    return this->m*this->a*(1/X-0.5)*this->dX_dtau(tau, delta);
-}
-long double ResidualHelmholtzSAFTAssociating::dTau2(const long double &tau, const long double &delta) throw()
-{
-    if (disabled){return 0;}
-    long double X = this->X(delta, this->Deltabar(tau, delta));
-    long double X_tau = this->dX_dtau(tau, delta);
-    long double X_tautau = this->d2X_dtau2(tau, delta);
-    return this->m*this->a*((1/X-0.5)*X_tautau-pow(X_tau/X, 2));
-}
-long double ResidualHelmholtzSAFTAssociating::dDelta2(const long double &tau, const long double &delta) throw()
-{
-    if (disabled){return 0;}
-    long double X = this->X(delta, this->Deltabar(tau, delta));
-    long double X_delta = this->dX_ddelta(tau, delta);
-    long double X_deltadelta = this->d2X_ddelta2(tau, delta);
-    return this->m*this->a*((1/X-0.5)*X_deltadelta-pow(X_delta/X,2));
-}
-long double ResidualHelmholtzSAFTAssociating::dDelta_dTau(const long double &tau, const long double &delta) throw()
-{
-    if (disabled){return 0;}
-    long double X = this->X(delta, this->Deltabar(tau, delta));
-    long double X_delta = this->dX_ddelta(tau, delta);
-    long double X_tau = this->dX_dtau(tau, delta);
-    long double X_deltatau = this->d2X_ddeltadtau(tau, delta);
-    return this->m*this->a*((-X_tau/X/X)*X_delta+X_deltatau*(1/X-0.5));
-}
-long double ResidualHelmholtzSAFTAssociating::dTau3(const long double &tau, const long double &delta) throw()
-{
-    if (disabled){return 0;}
-    long double X = this->X(delta, this->Deltabar(tau, delta));
-    long double X_t = this->dX_dtau(tau, delta);
-    long double X_tt = this->d2X_dtau2(tau, delta);
-    long double X_ttt = this->d3X_dtau3(tau, delta);
-    return this->m*this->a*((1/X-1.0/2.0)*X_ttt+(-X_t/pow(X,(int)2))*X_tt-2*(pow(X,(int)2)*(X_t*X_tt)-pow(X_t,(int)2)*(X*X_t))/pow(X,(int)4));
-}
-long double ResidualHelmholtzSAFTAssociating::dDelta_dTau2(const long double &tau, const long double &delta) throw()
-{
-    if (disabled){return 0;}
-    long double X = this->X(delta, this->Deltabar(tau, delta));
-    long double X_t = this->dX_dtau(tau, delta);
-    long double X_d = this->dX_ddelta(tau, delta);
-    long double X_tt = this->d2X_dtau2(tau, delta);
-    long double X_dt = this->d2X_ddeltadtau(tau, delta);
-    long double X_dtt = this->d3X_ddeltadtau2(tau, delta);
-    return this->m*this->a*((1/X-1.0/2.0)*X_dtt-X_d/pow(X,(int)2)*X_tt-2*(pow(X,(int)2)*(X_t*X_dt)-pow(X_t,(int)2)*(X*X_d))/pow(X,(int)4));
-}
-long double ResidualHelmholtzSAFTAssociating::dDelta2_dTau(const long double &tau, const long double &delta) throw()
-{
-    if (disabled){return 0;}
-    long double X = this->X(delta, this->Deltabar(tau, delta));
-    long double X_t = this->dX_dtau(tau, delta);
-    long double X_d = this->dX_ddelta(tau, delta);
-    long double X_dd = this->d2X_ddelta2(tau, delta);
-    long double X_dt = this->d2X_ddeltadtau(tau, delta);
-    long double X_ddt = this->d3X_ddelta2dtau(tau, delta);
-    return this->m*this->a*((1/X-1.0/2.0)*X_ddt-X_t/pow(X,(int)2)*X_dd-2*(pow(X,(int)2)*(X_d*X_dt)-pow(X_d,(int)2)*(X*X_t))/pow(X,(int)4));
-}
-long double ResidualHelmholtzSAFTAssociating::dDelta3(const long double &tau, const long double &delta) throw()
-{
-    if (disabled){return 0;}
-    long double X = this->X(delta, this->Deltabar(tau, delta));
-    long double X_d = this->dX_ddelta(tau, delta);
-    long double X_dd = this->d2X_ddelta2(tau, delta);
-    long double X_ddd = this->d3X_ddelta3(tau, delta);
-    return this->m*this->a*((1/X-1.0/2.0)*X_ddd-X_d/pow(X,(int)2)*X_dd-2*(pow(X,(int)2)*(X_d*X_dd)-pow(X_d,(int)2)*(X*X_d))/pow(X,(int)4));
-}
 
+void ResidualHelmholtzSAFTAssociating::all(const long double &tau, const long double &delta, Derivatives &deriv) throw()
+{
+    if (disabled){return;}
+    long double X = this->X(delta, this->Deltabar(tau, delta));
+    long double X_t = this->dX_dtau(tau, delta);
+    long double X_d = this->dX_ddelta(tau, delta);
+    long double X_tt = this->d2X_dtau2(tau, delta);
+    long double X_dd = this->d2X_ddelta2(tau, delta);
+    long double X_dt = this->d2X_ddeltadtau(tau, delta);
+    long double X_ttt = this->d3X_dtau3(tau, delta);
+    long double X_dtt = this->d3X_ddeltadtau2(tau, delta);
+    long double X_ddt = this->d3X_ddelta2dtau(tau, delta);
+    long double X_ddd = this->d3X_ddelta3(tau, delta);
+    
+    deriv.alphar += this->m*this->a*((log(X)-X/2.0+0.5));
+    deriv.dalphar_ddelta += this->m*this->a*(1/X-0.5)*this->dX_ddelta(tau, delta);
+    deriv.dalphar_dtau += this->m*this->a*(1/X-0.5)*this->dX_dtau(tau, delta);
+    deriv.d2alphar_dtau2 += this->m*this->a*((1/X-0.5)*X_tt-pow(X_t/X, 2));
+    deriv.d2alphar_ddelta2 += this->m*this->a*((1/X-0.5)*X_dd-pow(X_d/X,2));
+    deriv.d2alphar_ddelta_dtau += this->m*this->a*((-X_t/X/X)*X_d + X_dt*(1/X-0.5));
+    deriv.d3alphar_dtau3 += this->m*this->a*((1/X-1.0/2.0)*X_ttt+(-X_t/pow(X,(int)2))*X_tt-2*(pow(X,(int)2)*(X_t*X_tt)-pow(X_t,(int)2)*(X*X_t))/pow(X,(int)4));
+    deriv.d3alphar_ddelta_dtau2 += this->m*this->a*((1/X-1.0/2.0)*X_dtt-X_d/pow(X,(int)2)*X_tt-2*(pow(X,(int)2)*(X_t*X_dt)-pow(X_t,(int)2)*(X*X_d))/pow(X,(int)4));
+    deriv.d3alphar_ddelta2_dtau += this->m*this->a*((1/X-1.0/2.0)*X_ddt-X_t/pow(X,(int)2)*X_dd-2*(pow(X,(int)2)*(X_d*X_dt)-pow(X_d,(int)2)*(X*X_t))/pow(X,(int)4));
+    deriv.d3alphar_ddelta3 += this->m*this->a*((1/X-1.0/2.0)*X_ddd-X_d/pow(X,(int)2)*X_dd-2*(pow(X,(int)2)*(X_d*X_dd)-pow(X_d,(int)2)*(X*X_d))/pow(X,(int)4));
+}
 
 void IdealHelmholtzCP0PolyT::to_json(rapidjson::Value &el, rapidjson::Document &doc)
 {
diff --git a/src/main.cxx b/src/main.cxx
index 4031c4d1..80b0d302 100644
--- a/src/main.cxx
+++ b/src/main.cxx
@@ -163,7 +163,7 @@ int main()
 		double rrv = CoolProp::PropsSI("C","T",300,"D",1e-10,"REFPROP::R1234ze");
 		
 		std::cout << get_global_param_string("errstring");
-        double rr0 = HumidAir::HAPropsSI("B","T",473.15,"W",0.5,"P",101325);
+        double rr0 = HumidAir::HAPropsSI("S","T",473.15,"W",0,"P",1e6);
         //CoolProp::set_reference_stateS("Air","RESET");
         double rr1 = HumidAir::HAPropsSI("B","T",473.15,"W",0.5,"P",101325);
         int r = 1;
@@ -505,34 +505,23 @@ int main()
         
         Derivatives derivs;
         time_t t1,t2;
-        long N = 10000;
+        long N = 100000;
         double ss = 0;
         
         std::vector<CoolPropFluid*> components = Water->get_components();
-        ResidualHelmholtzPower Power = components[0]->pEOS->alphar.Power;
+        ResidualHelmholtzGeneralizedExponential GenExp = components[0]->pEOS->alphar.GenExp;
+        
         long double tau = 0.8, delta = 2.2;
+        
+        GenExp.all(tau, delta, derivs);
+        
         t1 = clock();
         for (long i = 0; i < N; ++i){
-            Power.all(tau, delta+i*1e-10, derivs);
+            GenExp.all(tau, delta+i*1e-10, derivs);
             ss += derivs.alphar+derivs.dalphar_ddelta+derivs.dalphar_dtau+derivs.d2alphar_ddelta2+derivs.d2alphar_ddelta_dtau+derivs.d2alphar_dtau2;
         }
         t2 = clock();
-        std::cout << format("value: %0.13g, %g us/call", ss, ((double)(t2-t1))/CLOCKS_PER_SEC/double(N)*1e6);
-        
-
-        ss = 0;
-        t1 = clock();
-        for (long i = 0; i < N; ++i){
-            long double alphar = Power.base(tau, delta+i*1e-10);
-            long double dalphar_ddelta = Power.dDelta(tau, delta+i*1e-10);
-            long double dalphar_dtau = Power.dTau(tau, delta+i*1e-10);
-            long double d2alphar_ddelta2 = Power.dDelta2(tau, delta+i*1e-10);
-            long double d2alphar_ddelta_dtau = Power.dDelta_dTau(tau, delta+i*1e-10);
-            long double d2alphar_dtau2 = Power.dTau2(tau, delta+i*1e-10);
-            ss += alphar+dalphar_ddelta+dalphar_dtau+d2alphar_ddelta2+d2alphar_ddelta_dtau+d2alphar_dtau2;
-        }
-        t2 = clock();
-        std::cout << format("value: %0.13g, %g us/call", ss, ((double)(t2-t1))/CLOCKS_PER_SEC/double(N)*1e6);
+        std::cout << format("value: %0.13g, %g us/call\n", ss, ((double)(t2-t1))/CLOCKS_PER_SEC/double(N)*1e6);
         
         exit(0);
     }