diff --git a/include/Helmholtz.h b/include/Helmholtz.h
index b99dfbe9..55039bee 100644
--- a/include/Helmholtz.h
+++ b/include/Helmholtz.h
@@ -99,14 +99,14 @@ public:
 // #############################################################################
 // #############################################################################
 
-struct Derivatives
+struct HelmholtzDerivatives
 {
     long double alphar, dalphar_ddelta, dalphar_dtau, d2alphar_ddelta2, d2alphar_dtau2, d2alphar_ddelta_dtau, 
                 d3alphar_ddelta3, d3alphar_ddelta_dtau2, d3alphar_ddelta2_dtau, d3alphar_dtau3;
     void reset(){alphar = 0; dalphar_ddelta = 0; dalphar_dtau = 0; d2alphar_ddelta2 = 0; d2alphar_dtau2 = 0; d2alphar_ddelta_dtau = 0;
                 d3alphar_ddelta3 = 0; d3alphar_ddelta_dtau2 = 0; d3alphar_ddelta2_dtau = 0; d3alphar_dtau3 = 0;
                 }
-    Derivatives(){reset();};
+    HelmholtzDerivatives(){reset();};
 };
 
 struct ResidualHelmholtzGeneralizedExponentialElement
@@ -269,7 +269,7 @@ public:
     long double dDelta_dTau2(const long double &tau, const long double &delta) throw(){return 0;};
     long double dTau3(const long double &tau, const long double &delta) throw(){return 0;};
     
-    void all(const long double &tau, const long double &delta, Derivatives &derivs) throw();
+    void all(const long double &tau, const long double &delta, HelmholtzDerivatives &derivs) throw();
 };
 
 struct ResidualHelmholtzNonAnalyticElement
@@ -327,7 +327,7 @@ public:
     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();
     
-    void all(const long double &tau, const long double &delta, Derivatives &derivs) throw();
+    void all(const long double &tau, const long double &delta, HelmholtzDerivatives &derivs) throw();
 };
 
 class ResidualHelmholtzSAFTAssociating : public BaseHelmholtzTerm{
@@ -383,18 +383,18 @@ public:
 
     void to_json(rapidjson::Value &el, rapidjson::Document &doc);
 
-    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;};
+    long double base(const long double &tau, const long double &delta) throw(){HelmholtzDerivatives deriv; all(tau,delta,deriv); return deriv.alphar;};
+    long double dDelta(const long double &tau, const long double &delta) throw(){HelmholtzDerivatives deriv; all(tau,delta,deriv); return deriv.dalphar_ddelta;};
+    long double dTau(const long double &tau, const long double &delta) throw(){HelmholtzDerivatives deriv; all(tau,delta,deriv); return deriv.dalphar_dtau;};
+    long double dDelta2(const long double &tau, const long double &delta) throw(){HelmholtzDerivatives deriv; all(tau,delta,deriv); return deriv.d2alphar_ddelta2;};
+    long double dDelta_dTau(const long double &tau, const long double &delta) throw(){HelmholtzDerivatives deriv; all(tau,delta,deriv); return deriv.d2alphar_ddelta_dtau;};
+    long double dTau2(const long double &tau, const long double &delta) throw(){HelmholtzDerivatives deriv; all(tau,delta,deriv); return deriv.d2alphar_dtau2;};
+    long double dDelta3(const long double &tau, const long double &delta) throw(){HelmholtzDerivatives deriv; all(tau,delta,deriv); return deriv.d3alphar_ddelta3;};
+    long double dDelta2_dTau(const long double &tau, const long double &delta) throw(){HelmholtzDerivatives deriv; all(tau,delta,deriv); return deriv.d3alphar_ddelta2_dtau;};
+    long double dDelta_dTau2(const long double &tau, const long double &delta) throw(){HelmholtzDerivatives deriv; all(tau,delta,deriv); return deriv.d3alphar_ddelta_dtau2;};
+    long double dTau3(const long double &tau, const long double &delta) throw(){HelmholtzDerivatives deriv; all(tau,delta,deriv); return deriv.d3alphar_dtau3;};
     
-    void all(const long double &tau, const long double &delta, Derivatives &deriv) throw();
+    void all(const long double &tau, const long double &delta, HelmholtzDerivatives &deriv) throw();
 };
 
 class ResidualHelmholtzContainer
@@ -405,75 +405,24 @@ public:
     ResidualHelmholtzSAFTAssociating SAFT;
     ResidualHelmholtzGeneralizedExponential GenExp; 
 
-    Derivatives all(const long double tau, const long double delta)
+    HelmholtzDerivatives all(const long double tau, const long double delta)
     {
-        Derivatives derivs; // zeros out the elements
+        HelmholtzDerivatives derivs; // zeros out the elements
         GenExp.all(tau, delta, derivs);
         NonAnalytic.all(tau, delta, derivs);
         SAFT.all(tau, delta, derivs);
         return derivs;
     };
-    long double base(long double tau, long double delta)
-    {
-        Derivatives derivs; // zeros out the elements
-        GenExp.all(tau, delta, derivs);
-        return (derivs.alphar + NonAnalytic.base(tau, delta) + SAFT.base(tau,delta));
-    };
-    long double dDelta(long double tau, long double delta)
-    {
-        Derivatives derivs;
-        GenExp.all(tau, delta, derivs);
-        return (derivs.dalphar_ddelta + NonAnalytic.dDelta(tau, delta) + SAFT.dDelta(tau,delta));
-    };
-    long double dTau(long double tau, long double delta)
-    {
-        Derivatives derivs;
-        GenExp.all(tau, delta, derivs);
-        return (derivs.dalphar_dtau + NonAnalytic.dTau(tau, delta) + SAFT.dTau(tau,delta));
-    };
-    long double dDelta2(long double tau, long double delta)
-    {
-        Derivatives derivs;
-        GenExp.all(tau, delta, derivs);
-        return (derivs.d2alphar_ddelta2 + NonAnalytic.dDelta2(tau, delta) + SAFT.dDelta2(tau,delta));
-    };
-    long double dDelta_dTau(long double tau, long double delta)
-    {
-        Derivatives derivs;
-        GenExp.all(tau, delta, derivs);
-        return (derivs.d2alphar_ddelta_dtau + NonAnalytic.dDelta_dTau(tau, delta) + SAFT.dDelta_dTau(tau,delta));
-    };
-    long double dTau2(long double tau, long double delta)
-    {
-        Derivatives derivs;
-        GenExp.all(tau, delta, derivs);
-        return (derivs.d2alphar_dtau2 + NonAnalytic.dTau2(tau, delta) + SAFT.dTau2(tau,delta));
-    };
-    
-    long double dDelta3(long double tau, long double delta) 
-    {
-        Derivatives derivs;
-        GenExp.all(tau, delta, derivs);
-        return (derivs.d3alphar_ddelta3 + NonAnalytic.dDelta3(tau, delta) + SAFT.dDelta3(tau,delta));
-    };
-    long double dDelta2_dTau(long double tau, long double delta)
-    {
-        Derivatives derivs;
-        GenExp.all(tau, delta, derivs);
-        return (derivs.d3alphar_ddelta2_dtau + NonAnalytic.dDelta2_dTau(tau, delta) + SAFT.dDelta2_dTau(tau,delta));
-    };
-    long double dDelta_dTau2(long double tau, long double delta)
-    {
-        Derivatives derivs;
-        GenExp.all(tau, delta, derivs);
-        return (derivs.d3alphar_ddelta_dtau2 + NonAnalytic.dDelta_dTau2(tau, delta) + SAFT.dDelta_dTau2(tau,delta));
-    };
-    long double dTau3(long double tau, long double delta)
-    {
-        Derivatives derivs;
-        GenExp.all(tau, delta, derivs);
-        return (derivs.d3alphar_dtau3 + NonAnalytic.dTau3(tau, delta) + SAFT.dTau3(tau,delta));
-    };
+    long double base(long double tau, long double delta) { return all(tau,delta).alphar; };
+    long double dDelta(long double tau, long double delta) { return all(tau,delta).dalphar_ddelta; };
+    long double dTau(long double tau, long double delta) { return all(tau, delta).dalphar_dtau; };
+    long double dDelta2(long double tau, long double delta) {  return all(tau, delta).d2alphar_ddelta2; };
+    long double dDelta_dTau(long double tau, long double delta) { return all(tau, delta).d2alphar_ddelta_dtau; };
+    long double dTau2(long double tau, long double delta) { return all(tau, delta).d2alphar_dtau2; };
+    long double dDelta3(long double tau, long double delta) { return all(tau, delta).d3alphar_ddelta3; };
+    long double dDelta2_dTau(long double tau, long double delta) { return all(tau, delta).d3alphar_ddelta2_dtau; };
+    long double dDelta_dTau2(long double tau, long double delta) { return all(tau, delta).d3alphar_ddelta_dtau2; };
+    long double dTau3(long double tau, long double delta) { return all(tau, delta).d3alphar_dtau3; };
 };
 
 // #############################################################################
diff --git a/src/Helmholtz.cpp b/src/Helmholtz.cpp
index fecafffe..278b5a9a 100644
--- a/src/Helmholtz.cpp
+++ b/src/Helmholtz.cpp
@@ -18,7 +18,7 @@ long double kahanSum(std::vector<long double> &x)
 }
 bool wayToSort(long double i, long double j) { return std::abs(i) > std::abs(j); }
 
-void ResidualHelmholtzGeneralizedExponential::all(const long double &tau, const long double &delta, Derivatives &derivs) throw()
+void ResidualHelmholtzGeneralizedExponential::all(const long double &tau, const long double &delta, HelmholtzDerivatives &derivs) throw()
 {
     long double log_tau = log(tau), log_delta = log(delta), ndteu, 
                 u, du_ddelta, du_dtau, d2u_ddelta2, d2u_dtau2, d3u_ddelta3, d3u_dtau3,
@@ -176,7 +176,7 @@ void ResidualHelmholtzNonAnalytic::to_json(rapidjson::Value &el, rapidjson::Docu
     el.AddMember("D",_D,doc.GetAllocator());
 }
 
-void ResidualHelmholtzNonAnalytic::all(const long double &tau, const long double &delta, Derivatives &derivs) throw()
+void ResidualHelmholtzNonAnalytic::all(const long double &tau, const long double &delta, HelmholtzDerivatives &derivs) throw()
 {
     if (N==0){return;}
     for (unsigned int i=0; i<N; ++i)
@@ -785,7 +785,7 @@ long double ResidualHelmholtzSAFTAssociating::eta(const long double &delta){
     return this->vbarn*delta;
 }
 
-void ResidualHelmholtzSAFTAssociating::all(const long double &tau, const long double &delta, Derivatives &deriv) throw()
+void ResidualHelmholtzSAFTAssociating::all(const long double &tau, const long double &delta, HelmholtzDerivatives &deriv) throw()
 {
     if (disabled){return;}
     long double X = this->X(delta, this->Deltabar(tau, delta));
diff --git a/src/main.cxx b/src/main.cxx
index bf9f3866..11a42c2c 100644
--- a/src/main.cxx
+++ b/src/main.cxx
@@ -413,11 +413,11 @@ int main()
         int rr = 0;
     }
     #endif
-    #if 0
+    #if 1
     {
         #if ENABLE_CATCH
             std::vector<std::string> tags;
-            tags.push_back("[ancillaries]");
+            tags.push_back("[helmholtz]");
             run_user_defined_tests(tags);
             double rr = 0;
 			char c;
@@ -503,7 +503,7 @@ int main()
         shared_ptr<HelmholtzEOSMixtureBackend> Water(new HelmholtzEOSMixtureBackend(names));
         Water->set_mole_fractions(std::vector<long double>(1,1));
         
-        Derivatives derivs;
+        HelmholtzDerivatives derivs;
         time_t t1,t2;
         long N = 100000;
         double ss = 0;