chi_diffusion_bndry.h

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#ifndef CHI_DIFFUSION_BOUNDARY_H
#define CHI_DIFFUSION_BOUNDARY_H
 
#include "../chi_diffusion.h"
 
namespace chi_diffusion
{
  enum class BoundaryType : int
  {
    Reflecting = 1,
    Dirichlet  = 2,
    Neumann    = 3,
    Robin      = 4,
    Vacuum     = 5
  };
}
 
//###################################################################
/**Parent class for diffusion boundaries*/
class chi_diffusion::Boundary
{
public:
  BoundaryType type_;
 
  explicit
  Boundary(BoundaryType in_bndry_type) : type_(in_bndry_type) {}
};
 
//###################################################################
/**Reflecting boundary condition.*/
class chi_diffusion::BoundaryReflecting : public chi_diffusion::Boundary
{
public:
  BoundaryReflecting() : Boundary(BoundaryType::Reflecting) {}
};
 
//###################################################################
/**Dirichlet boundary.*/
class chi_diffusion::BoundaryDirichlet : public chi_diffusion::Boundary
{
public:
  double boundary_value=0.0;
 
public:
  BoundaryDirichlet() : Boundary(BoundaryType::Dirichlet) {}
  explicit
  BoundaryDirichlet(double in_bndry_value) :
    Boundary(BoundaryType::Dirichlet),
    boundary_value(in_bndry_value)
  {}
};
 
//###################################################################
/**Robin boundary condition. This type of boundary condition doubles
 * for any boundary condition of the form
 *
\f[
a \phi + b D \hat{n}\cdot \nabla \phi = f
\f]
 
When \f$ a=0\f$ the boundary condition is equivalent to a <B>Neumann</B>
boundary condition.
 
\f[
b D\hat{n}\cdot \nabla \phi = f
\f]
 
 When \f$ a=\frac{1}{4} \f$, \f$ b=\frac{1}{2} \f$
and \f$ f=0 \f$ then the boundary condition is equivalent to a
<B>Vacuum</B> boundary condition.
 
\f[
\frac{1}{4}\phi + \frac{1}{2}D\hat{n}\cdot \nabla \phi = 0
\f]
 */
class chi_diffusion::BoundaryRobin : public chi_diffusion::Boundary
{
public:
  double a=0.25;
  double b=0.5;
  double f=0.0;
public:
  BoundaryRobin(double a_value, double b_value, double f_value) :
    Boundary(BoundaryType::Robin)
  {
    a = a_value;
    b = b_value;
    f = f_value;
  }
 
};
 
 
#endif //CHI_DIFFUSION_BOUNDARY_H