changed: rename EvalFunc::derivative to EvalFunc::addDerivative

consistent with EvalFunction and more descriptive of what it does

src/Utility/ExprFunctions.C

@@ -146,7 +146,7 @@ void EvalFunc::cleanup ()
 }
 
 
-void EvalFunc::derivative (const std::string& function, const char* x)
+void EvalFunc::addDerivative (const std::string& function, const char* x)
 {
   if (!gradient)
     gradient = new EvalFunc(function.c_str(),x);

src/Utility/ExprFunctions.h

@@ -53,7 +53,7 @@ public:
   virtual ~EvalFunc();
 
   //! \brief Adds an expression function for a first derivative.
-  void derivative(const std::string& function, const char* x = "x");
+  void addDerivative(const std::string& function, const char* x = "x");
 
   //! \brief Returns whether the function is time-independent or not.
   virtual bool isConstant() const { return false; }

src/Utility/Functions.C

@@ -728,7 +728,7 @@ static const ScalarFunc* parseFunction (const char* type, char* cline, Real C)
     if (sf && (cline = strtok(nullptr,":")))
     {
       IFEM::cout <<" (derivative: "<< cline <<")";
-      static_cast<EvalFunc*>(sf)->derivative(cline,"t");
+      static_cast<EvalFunc*>(sf)->addDerivative(cline,"t");
     }
     return sf;
   }