demo_code.cc File Reference

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

Classes
class	OneDPoissonProblem< ELEMENT >
	1D Poisson problem in unit interval. More...

Namespaces
	FishSolnOneDPoisson
	Namespace for fish-shaped solution of 1D Poisson equation.

Functions
void	FishSolnOneDPoisson::get_exact_u (const Vector< double > &x, Vector< double > &u)
	Exact, fish-shaped solution as a 1D vector. More...
void	FishSolnOneDPoisson::source_function (const Vector< double > &x, double &source)
	Source function required to make the fish shape an exact solution. More...
int	main ()
	Driver for 1D Poisson problem. More...

Function Documentation

main()

int main

(

)

Driver for 1D Poisson problem.

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

{
 
 // Set up the problem: 
 // Solve a 1D Poisson problem using a source function that generates
 // a fish shaped exact solution
 unsigned n_element=40; //Number of elements
 OneDPoissonProblem<QPoissonElement<1,4> > //Element type as template parameter
  problem(n_element,FishSolnOneDPoisson::source_function);
 
 // Check whether the problem can be solved
 cout << "\n\n\nProblem self-test ";
 if (problem.self_test()==0)  
  {
   cout << "passed: Problem can be solved." << std::endl;
  }
 else 
  {
   throw OomphLibError("failed!",
                       OOMPH_CURRENT_FUNCTION,OOMPH_EXCEPTION_LOCATION);
  }
 
 // Set the sign of the source function:
 cout << "\n\n\nSolving with negative sign:\n" << std::endl;
 FishSolnOneDPoisson::Sign=-1;
 
 // Solve the problem with this Sign
 problem.newton_solve();
 
 //Output solution for this case (label output files with "0")
 problem.doc_solution(0);
 
 
 // Change the sign of the source function:
 cout << "\n\n\nSolving with positive sign:\n" << std::endl;
 FishSolnOneDPoisson::Sign=1;
 
 // Re-solve the problem with this Sign (boundary conditions get
 // updated automatically when Problem::actions_before_newton_solve() is
 // called.
 problem.newton_solve();
 
 //Output solution for this case (label output files with "1")
 problem.doc_solution(1);
 
} // end of main

References OOMPH_CURRENT_FUNCTION, OOMPH_EXCEPTION_LOCATION, problem, FishSolnOneDPoisson::Sign, and FishSolnOneDPoisson::source_function().