fish_poisson_no_adapt.cc

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//LIC//====================================================================
// Driver for solution of 2D Poisson equation in fish-shaped domain 
 
// Generic oomph-lib headers
#include "generic.h"
 
// The Poisson equations
#include "poisson.h"
 
// The fish mesh 
#include "meshes/fish_mesh.h"
 
using namespace std;
 
using namespace oomph;
 
//============ start_of_namespace=====================================
/// Namespace for const source term in Poisson equation
//====================================================================
namespace ConstSourceForPoisson
{ 
 
 /// Strength of source function: default value -1.0
 double Strength=-1.0;
 
/// Const source function
 void get_source(const Vector<double>& x, double& source)
 {
  source = Strength;
 }
 
} // end of namespace
 
 
 
 
//======start_of_problem_class========================================
///  Poisson problem in fish-shaped domain.
/// Template parameter identifies the element type.
//====================================================================
template<class ELEMENT>
class FishPoissonProblem : public Problem
{
 
public:
 
 /// Constructor
 FishPoissonProblem();
 
 /// Destructor: Empty
 virtual ~FishPoissonProblem(){}
 
 /// Update the problem specs after solve (empty)
 void actions_after_newton_solve() {}
 
 /// Update the problem specs before solve (empty)
 void actions_before_newton_solve() {}
 
 /// Overloaded version of the problem's access function to 
 /// the mesh. Recasts the pointer to the base Mesh object to 
 /// the actual mesh type.
 FishMesh<ELEMENT>* mesh_pt() 
  {
   return dynamic_cast<FishMesh<ELEMENT>*>(Problem::mesh_pt());
  }
 
 /// Doc the solution. Output directory and labels are specified 
 /// by DocInfo object
 void doc_solution(DocInfo& doc_info);
 
}; // end of problem class
 
 
 
 
 
//===========start_of_constructor=========================================
/// Constructor for Poisson problem in fish-shaped
/// domain.
//========================================================================
template<class ELEMENT>
FishPoissonProblem<ELEMENT>::FishPoissonProblem()
{ 
    
 // Build fish mesh -- this is a coarse base mesh consisting 
 // of four elements.
 Problem::mesh_pt()=new FishMesh<ELEMENT>;
 
 // Set the boundary conditions for this problem: All nodes are
 // free by default -- just pin the ones that have Dirichlet conditions
 // here. Since the boundary values are never changed, we set
 // them here rather than in actions_before_newton_solve(). 
 unsigned num_bound = mesh_pt()->nboundary();
 for(unsigned ibound=0;ibound<num_bound;ibound++)
  {
   unsigned num_nod= mesh_pt()->nboundary_node(ibound);
   for (unsigned inod=0;inod<num_nod;inod++)
    {
     // Pin the single scalar value at this node
     mesh_pt()->boundary_node_pt(ibound,inod)->pin(0); 
 
     // Assign the homogenous boundary condition to the one and
     // only nodal value
     mesh_pt()->boundary_node_pt(ibound,inod)->set_value(0,0.0); 
    }
  }
 
 // Loop over elements and set pointers to source function
 unsigned n_element = mesh_pt()->nelement();
 for(unsigned i=0;i<n_element;i++)
  {
   // Upcast from FiniteElement to the present element
   ELEMENT *el_pt = dynamic_cast<ELEMENT*>(mesh_pt()->element_pt(i));
 
   //Set the source function pointer
   el_pt->source_fct_pt() = &ConstSourceForPoisson::get_source;
  }
 
 // Setup the equation numbering scheme
 cout <<"Number of equations: " << assign_eqn_numbers() << std::endl; 
 
} // end of constructor
 
 
 
 
//=======start_of_doc=====================================================
/// Doc the solution in tecplot format.
//========================================================================
template<class ELEMENT>
void FishPoissonProblem<ELEMENT>::doc_solution(DocInfo& doc_info)
{ 
 
 ofstream some_file;
 char filename[100];
 
 // Number of plot points in each coordinate direction.
 unsigned npts;
 npts=5; 
 
 // Output solution 
 snprintf(filename, sizeof(filename), "%s/soln%i.dat",doc_info.directory().c_str(),
         doc_info.number());
 some_file.open(filename);
 mesh_pt()->output(some_file,npts);
 some_file.close();
 
} // end of doc
 
 
 
 
 
 
//=====================start_of_main======================================
/// Demonstrate how to solve 2D Poisson problem in 
/// fish-shaped domain.
//========================================================================
int main()
{
 
 //Set up the problem with 4 node Poisson elements
 FishPoissonProblem<QPoissonElement<2,2> > problem;
 
 // Setup labels for output
 //------------------------
 DocInfo doc_info;
 
 // Set output directory
 doc_info.set_directory("RESLT"); 
 
 // Step number
 doc_info.number()=0;
  
  
 // Solve/doc the problem
 //----------------------
 
 // Solve the problem
 problem.newton_solve();
 
 //Output solution
 problem.doc_solution(doc_info);
 
 //Increment counter for solutions 
 doc_info.number()++;
 
 
} // end of main