q_convergence_2d.cc File Reference

#include "generic.h"
#include "poisson.h"
#include "meshes/simple_rectangular_quadmesh.h"

Classes
class	PoissonProblem< ELEMENT >
	Micky mouse Poisson problem. More...

Namespaces
	TanhSolnForPoisson
	Namespace for exact solution for Poisson equation with "sharp step".

Functions
void	TanhSolnForPoisson::get_exact_u (const Vector< double > &x, Vector< double > &u)
	Exact solution as a Vector. More...
void	TanhSolnForPoisson::get_exact_u (const Vector< double > &x, double &u)
	Exact solution as a scalar. More...
void	TanhSolnForPoisson::get_source (const Vector< double > &x, double &source)
	Source function to make it an exact solution. More...
int	main (int argc, char *argv[])
	Demonstrate how to solve Poisson problem. More...

Function Documentation

main()

int main	(	int argc	,
		char *	argv[]
	)

Demonstrate how to solve Poisson problem.

///////////////////////////////////////////////////////////////////// ///////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////

Label for output

{
 
 // Store command line arguments
 CommandLineArgs::setup(argc,argv);
 
 DocInfo doc_info;
 
 // Output directory
 doc_info.set_directory("RESLT");
 
 // Step number
 doc_info.number()=0;
 
 //Set step orientation
 TanhSolnForPoisson::Beta=0.4;
 
 
 // Number of steps (reduced for validation)
 unsigned nstep = 7;  
 if (CommandLineArgs::Argc>1)
  {
   nstep=3;
  }
 
 // Output for convergence data
 ofstream convergence_file("RESLT/convergence.dat");
 
 convergence_file << "VARIABLES=\"log h\",\"log e\",\"theory\",\"log u\" " 
                  << std::endl;
 
 
 cout << "Linear elements " << std::endl;
 cout << "================" << std::endl << std::endl;
 
 
 //Tecplot output separator for convergence results
 convergence_file << "ZONE T=\"Linear element\"" << std::endl;
 for (unsigned h_power=1;h_power<nstep+1;h_power++)
  {
   //Set up the problem
   PoissonProblem<QPoissonElement<2,2> > 
    problem(&TanhSolnForPoisson::get_source,h_power);
   
 
   // Solve the problem
   problem.newton_solve();
   
   //Output solution & convergence data
   problem.doc_solution(doc_info,convergence_file);
   
   //Increment counter for solutions 
   doc_info.number()++;
  }
 
 
 
 cout << "Quadratic elements " << std::endl;
 cout << "==================" << std::endl << std::endl;
 
 
 //Tecplot output separator for convergence results
 convergence_file << "ZONE T=\"Quadratic element\"" << std::endl;
 for (unsigned h_power=1;h_power<nstep+1;h_power++)
  {
   //Set up the problem
   PoissonProblem<QPoissonElement<2,3> > 
    problem(&TanhSolnForPoisson::get_source,h_power);
 
 
//    // Create an instance of a lower-order integration scheme
//    Gauss<2,2>* int_pt=new Gauss<2,2>;
 
//   //Find number of elements in mesh
//   unsigned n_element = problem.mesh_pt()->nelement();
  
//   // Loop over the elements to set up element-specific 
//   // things that cannot be handled by constructor
//   for(unsigned i=0;i<n_element;i++)
//    {
//     //Set the a different integration scheme
//     problem.mesh_pt()->finite_element_pt(i)->set_integration_scheme(int_pt); 
//    }
 
   // Solve the problem
   problem.newton_solve();
   
   //Output solution & convergence data
   problem.doc_solution(doc_info,convergence_file);
   
   //Increment counter for solutions 
   doc_info.number()++;
  }
 
 
 
 cout << "Cubicc elements " << std::endl;
 cout << "================" << std::endl << std::endl;
 
 
 //Tecplot output separator for convergence results
 convergence_file << "ZONE T=\"Cubic element\"" << std::endl;
 for (unsigned h_power=1;h_power<nstep+1;h_power++)
  {
   //Set up the problem
   PoissonProblem<QPoissonElement<2,4> > 
    problem(&TanhSolnForPoisson::get_source,h_power);
   
 
//    // Create an instance of a lower-order integration scheme
//    Gauss<2,3>* int_pt=new Gauss<2,3>;
 
//   //Find number of elements in mesh
//   unsigned n_element = problem.mesh_pt()->nelement();
  
//   // Loop over the elements to set up element-specific 
//   // things that cannot be handled by constructor
//   for(unsigned i=0;i<n_element;i++)
//    {
//     //Set the a different integration scheme
//     problem.mesh_pt()->finite_element_pt(i)->set_integration_scheme(int_pt); 
//    }
 
   // Solve the problem
   problem.newton_solve();
   
   //Output solution & convergence data
   problem.doc_solution(doc_info,convergence_file);
   
   //Increment counter for solutions 
   doc_info.number()++;
  }
 
 convergence_file.close();
 
}

References oomph::CommandLineArgs::Argc, TanhSolnForPoisson::Beta, TanhSolnForPoisson::get_source(), oomph::DocInfo::number(), problem, oomph::DocInfo::set_directory(), and Flag_definition::setup().