dg : raise an error when funciontSolution.getNbCol is called

Solver/function.h

@@ -68,7 +68,7 @@ class function {
 
   // get or print information
   inline bool isInvalitedOnElement() { return _invalidatedOnElement; }
-  inline int getNbCol() const        { return _nbCol; }
+  inline int getNbCol() const        {if(_nbCol ==0) Msg::Error("Cannot ask nbCol of functionSolution"); return _nbCol; }
   static functionConstant *getTime();
   static functionConstant *getDT();
   static function *getSolution();

gmshpy/gmshSolver.i

@@ -11,6 +11,7 @@
   #include "dofManager.h"
   #include "elasticitySolver.h"
   #include "function.h"
+  #include "functionDerivator.h"
   #include "functionPython.h"
   #include "linearSystem.h"
   #include "linearSystemCSR.h"
@@ -28,6 +29,7 @@ namespace std {
 %template(dofManagerDouble) dofManager<double>;
 %include "elasticitySolver.h"
 %include "function.h"
+%include "functionDerivator.h"
 %include "functionPython.h"
 %include "linearSystem.h"
 %template(linearSystemDouble) linearSystem<double>;