new GPFilter allows averaging in the current volume

NonLinearSolver/nlsolver/GPFilter.cpp

@@ -17,6 +17,17 @@ double GPFilterTrivial::getFactor(const IPVariable* ipvcur, const IPVariable* ip
 GPFilter* GPFilterTrivial::clone() const {return new GPFilterTrivial(*this);};
 
 
+GPFilterCurrentVolume::GPFilterCurrentVolume(): GPFilter(){};
+GPFilterCurrentVolume::GPFilterCurrentVolume(const GPFilterCurrentVolume& src):GPFilter(src){}; 
+GPFilterCurrentVolume::~GPFilterCurrentVolume(){}
+std::string GPFilterCurrentVolume::getName() const  {return "CurrentVolume";}
+double GPFilterCurrentVolume::getFactor(const IPVariable* ipvcur, const IPVariable* ipvprev) const 
+{
+  return ipvcur->get(IPField::JACOBIAN);
+};
+GPFilter* GPFilterCurrentVolume::clone() const {return new GPFilterCurrentVolume(*this);};
+
+
 GPFilterCoalescence::GPFilterCoalescence(const std::string name): GPFilter(), _name(name){};
 GPFilterCoalescence::GPFilterCoalescence(const GPFilterCoalescence& src):GPFilter(src),_name(src._name){}; 
 GPFilterCoalescence::~GPFilterCoalescence(){}

NonLinearSolver/nlsolver/GPFilter.h

@@ -37,6 +37,20 @@ class GPFilterTrivial : public GPFilter
     #endif
 };
 
+class GPFilterCurrentVolume : public GPFilter
+{
+  public:
+    GPFilterCurrentVolume();
+    GPFilterCurrentVolume(const GPFilterCurrentVolume& src); 
+    virtual ~GPFilterCurrentVolume();
+    #ifndef SWIG
+    virtual std::string getName() const;
+    virtual double getFactor(const IPVariable* ipvcur, const IPVariable* ipvprev) const;
+    virtual GPFilter* clone() const;
+    #endif
+};
+
+
 class GPFilterCoalescence : public GPFilter
 {
   protected: