converting routines for phasefields and signed distance functions

extensions/PhaseFieldConvert.h

@@ -5,6 +5,10 @@
 
 using namespace AMDiS;
 
+/// \brief
+/// Converts an AbstractFunction <i>dist</i>, that describes a signed distance function, to
+/// a phasefield function <i>p</i>, by \f$ \frac{1}{2}(1 - tanh(s \cdot dist(x) / \epsilon))\f$
+///
 struct SignedDistFctToPhaseField : AbstractFunction<double, WorldVector<double> >
 {
   SignedDistFctToPhaseField(double epsilon_, 
@@ -27,6 +31,67 @@ private:
   double scalingFactor;
 };
 
+
+/// \brief
+/// Converts a DOFVector, that describes a signed distance function, to
+/// a phasefield function <i>p</i>, by \f$ \frac{1}{2}(1 - tanh(s \cdot dist / \epsilon))\f$.
+/// You have to use <i>transformDOF</i> to apply this function to the DOFVector <i>dist</i>.
+///
+struct SignedDistToPhaseField : AbstractFunction<double, double>
+{
+  SignedDistToPhaseField(double epsilon_ = -1.0, double scalingFactor_ = 1.0/sqrt(2.0))
+  : AbstractFunction<double, double>(6),
+    epsilon(epsilon_),
+    scalingFactor(scalingFactor_)
+  {
+    if (epsilon < 0.0)
+      Parameters::get("mesh->refinement->epsilon", epsilon);
+  }
+  
+  double operator()(const double &dist) const
+  {
+    return 0.5 * (1.0 - tanh(scalingFactor * dist / epsilon));
+  }
+  
+private:
+  double epsilon;
+  double scalingFactor;
+};
+
+
+/// \brief
+/// Converts a DOFVector, that describes a signed distance function, to
+/// a phasefield function <i>p</i> with values in [-1,1], by \f$ - tanh(s \cdot dist / \epsilon)\f$.
+/// You have to use <i>transformDOF</i> to apply this function to the DOFVector <i>dist</i>.
+///
+struct SignedDistToCh : AbstractFunction<double, double>
+{
+  SignedDistToCh(double epsilon_ = -1.0, double scalingFactor_ = 1.0/sqrt(2.0))
+  : AbstractFunction<double, double>(6),
+    epsilon(epsilon_),
+    scalingFactor(scalingFactor_)
+  {
+    if (epsilon < 0.0)
+      Parameters::get("mesh->refinement->epsilon", epsilon);
+  }
+  
+  double operator()(const double &dist) const
+  {
+    return -tanh(scalingFactor * dist / epsilon);
+  }
+  
+private:
+  double epsilon;
+  double scalingFactor;
+};
+
+
+/// \brief
+/// Converts a vector of AbstractFunctions <i>{dist_i}</i>, that describe signed distance functions, to
+/// a phasefield function <i>p</i>, by \f$ \frac{1}{2}(1 - tanh(s \cdot \min_i(dist_i(x)) / \epsilon))\f$.
+/// The minimum of all distance function describes the union of the areas of negative values, of the 
+/// distance functions.
+///
 struct SignedDistFctListToPhaseField : AbstractFunction<double, WorldVector<double> >
 {
   SignedDistFctListToPhaseField(double epsilon_, 
@@ -54,6 +119,10 @@ private:
 };
 
 
+/// \brief
+/// Calculates the maximum of vector of distance function. This describes the intersections of the areas
+/// of negative values, of the distance functions.
+///
 struct SignedDistList : AbstractFunction<double, WorldVector<double> >
 {
   SignedDistList(std::vector<AbstractFunction<double,WorldVector<double> >*> dist_)
@@ -89,6 +158,14 @@ private:
   std::vector<AbstractFunction<double,WorldVector<double> >*> dist;
 };
 
+
+/// \brief
+/// Converts a DOFVector, that describes a phasefield function <i>phi</i>, to
+/// a signed distance function <i>dist</i>, by \f$ atanh(-\phi)\cdot\epsilon/s \f$.
+/// You have to use <i>transformDOF</i> to apply this function to the DOFVector <i>phi</i>.
+/// the phasefield values are cutted to allow the atanh calculation, by
+/// \f$ \phi:=\max(-1 + 10^{-10}, min(1-10^{-10}, \phi) ) \f$
+///
 struct PhaseFieldToSignedDist : AbstractFunction<double, double>
 {
   PhaseFieldToSignedDist(double epsilon_= -1.0, double scalingFactor_ = 1.0/sqrt(2.0))
@@ -111,48 +188,13 @@ private:
   double scalingFactor;
 };
 
-struct SignedDistToPhaseField : AbstractFunction<double, double>
-{
-  SignedDistToPhaseField(double epsilon_ = -1.0, double scalingFactor_ = 1.0/sqrt(2.0))
-  : AbstractFunction<double, double>(6),
-    epsilon(epsilon_),
-    scalingFactor(scalingFactor_)
-  {
-    if (epsilon < 0.0)
-      Parameters::get("mesh->refinement->epsilon", epsilon);
-  }
-  
-  double operator()(const double &dist) const
-  {
-    return 0.5 * (1.0 - tanh(scalingFactor * dist / epsilon));
-  }
-  
-private:
-  double epsilon;
-  double scalingFactor;
-};
-
-struct SignedDistToCh : AbstractFunction<double, double>
-{
-  SignedDistToCh(double epsilon_ = -1.0, double scalingFactor_ = 1.0/sqrt(2.0))
-  : AbstractFunction<double, double>(6),
-    epsilon(epsilon_),
-    scalingFactor(scalingFactor_)
-  {
-    if (epsilon < 0.0)
-      Parameters::get("mesh->refinement->epsilon", epsilon);
-  }
-  
-  double operator()(const double &dist) const
-  {
-    return -tanh(scalingFactor * dist / epsilon);
-  }
-  
-private:
-  double epsilon;
-  double scalingFactor;
-};
 
+/// \brief
+/// Converts a DOFVector, that describes a phasefield function <i>c</i> with
+/// values in [-1, 1], to a phasefield function with values in [0,1], by 
+/// \f$ \frac{1}{2}(c + 1) \f$.
+/// You have to use <i>transformDOF</i> to apply this function to the DOFVector <i>phi</i>.
+///
 struct ChToPhaseField : AbstractFunction<double, double>
 {
   ChToPhaseField() : AbstractFunction<double, double>(1) {};
@@ -162,6 +204,13 @@ struct ChToPhaseField : AbstractFunction<double, double>
   }
 };
 
+
+/// \brief
+/// Converts a DOFVector, that describes a phasefield function <i>phi</i> with
+/// values in [0, 1], to a phasefield function with values in [-1,1], by 
+/// \f$ 2\cdot\phi-1 \f$.
+/// You have to use <i>transformDOF</i> to apply this function to the DOFVector <i>phi</i>.
+///
 struct PhaseFieldToCh : AbstractFunction<double, double>
 {
   PhaseFieldToCh() : AbstractFunction<double, double>(1) {};