two_d_poisson_stored_shape_fcts.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::source_function (const Vector< double > &x, double &source)
	Source function required to make the solution above an exact solution. More...
int	main (int argc, char *argv[])
	Driver code for 2D Poisson problem. More...

Function Documentation

main()

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

Driver code for 2D Poisson problem.

{
 // Number of uniform refinements relative to a 2x2 base mesh
 unsigned n_refine;
 
 // Get number of refinement levels from command line or use default
 if (argc==1)
  {
   n_refine=6; //5
  }
 else if (argc==2)
  {
   n_refine=atoi(argv[1]);
  }
 else
  {
   std::string error_message =
    "Wrong number of input arguments. The options are: \n";
   error_message +=
    "No args: Default number of refinements\n";
   error_message +=
    "One arg: Required number of refinements\n";
 
   throw OomphLibError(error_message,
                       OOMPH_CURRENT_FUNCTION,
                       OOMPH_EXCEPTION_LOCATION);
  }
 
 
  cout << sizeof(Shape) << std::endl;
  cout << sizeof(DShape) << std::endl;
 // Create label for output
 //------------------------
 DocInfo doc_info;
 
 // Set output directory
 doc_info.set_directory("RESLT");
 
 // Step number
 doc_info.number()=0;
 
 
 // Set the orientation of the "step" to 45 degrees
 TanhSolnForPoisson::TanPhi=1.0;
 
 // Initial value for the steepness of the "step"
 TanhSolnForPoisson::Alpha=1.0; 
 
 
 
 
 //Set up the problem with normal Poisson elements
 //-----------------------------------------------
 {
  //  Initialise timers
  clock_t t_start = clock();
  
  // Create the problem with 2D nine-node elements from the
  // QPoissonElement family. Pass pointer to source function
  // and number of refinements required
  PoissonProblem<QPoissonElement<2,3> > 
   problem(&TanhSolnForPoisson::source_function,n_refine);
  
  // Finish/doc timing
  clock_t t_end = clock();
  double total_time=double(t_end-t_start)/CLOCKS_PER_SEC;
  cout << std::endl;
  cout << "======================================================= " << std::endl;
  cout << "Total time for Problem setup [sec]: " << total_time << std::endl;
  cout << "======================================================= " << std::endl;
  cout << std::endl;
  
  // Run problem
  problem.run_it(doc_info);
 }
 
 
 
 //Set up the problem with Poisson elements with storable shape fcts
 //-----------------------------------------------------------------
 {
  //  Initialise timers
  clock_t t_start = clock();
  
  typedef StorableShapeElement<QPoissonElement<2,3> >  ELEMENT;
  // Create the problem with 2D nine-node elements from the
  // QPoissonElement family. Pass pointer to source function
  // and number of refinements required
  PoissonProblem<ELEMENT> 
   problem(&TanhSolnForPoisson::source_function,n_refine);
  
  // Finish/doc timing
  clock_t t_end = clock();
  double total_time=double(t_end-t_start)/CLOCKS_PER_SEC;
  cout << std::endl;
  cout << "================================================================= " 
       << std::endl;
  cout << "Total time for Problem setup with storable shape fcts [sec]: " 
       << total_time << std::endl;
  cout << "================================================================= " 
       << std::endl;
  cout << std::endl;
  
  // Run problem with nothing stored (the default)
  //----------------------------------------------
  cout << "================================================================= "
       << std::endl;
  cout << "No shape functions actually stored                                "
       << std::endl;
  cout << "================================================================= "
       << std::endl << std::endl;
  problem.run_it(doc_info);
 
 
 
  // Store the derivatives w.r.t. to the Eulerian coordinates
  //-------------------------------------------------------------
  //  Initialise timers
  t_start = clock();
  unsigned nelem=problem.mesh_pt()->nelement();
  for (unsigned e=0;e<nelem;e++)
   {
    dynamic_cast<ELEMENT*>(problem.mesh_pt()->element_pt(e))
     ->pre_compute_dshape_eulerian_at_knots();
   }
 
  // Finish/doc timing
  t_end = clock();
  total_time=double(t_end-t_start)/CLOCKS_PER_SEC;
  cout << std::endl;
  cout << "================================================================= " 
       << std::endl;
  cout << "Total time for pre-calculation of shape functions and derivatives "
       << std::endl; 
  cout << total_time << " sec" <<  std::endl;
  cout << "================================================================= " 
       << std::endl;
  cout << std::endl;
  //Now run the problem
  problem.run_it(doc_info);
  
  // Set them all to refer to the first elements
  //-------------------------------------------------------------
  //  Initialise timers
  t_start = clock();
  for (unsigned e=1;e<nelem;e++)
   {
    dynamic_cast<ELEMENT*>(problem.mesh_pt()->element_pt(e))
     ->set_dshape_eulerian_stored_from_element(
      dynamic_cast<ELEMENT*>(problem.mesh_pt()->element_pt(0)));
   }
  // Finish/doc timing
  t_end = clock();
  total_time=double(t_end-t_start)/CLOCKS_PER_SEC;
  cout << std::endl;
  cout << "================================================================= " 
       << std::endl;
  cout << "Total time for assignment of shape functions and derivatives from "
       << std::endl << "the first element: " << total_time << " sec" <<  std::endl;
  cout << "================================================================= " 
       << std::endl;
  cout << std::endl;
 
  problem.run_it(doc_info);
 }
 
 
} //end of main

References TanhSolnForPoisson::Alpha, e(), OOMPH_CURRENT_FUNCTION, OOMPH_EXCEPTION_LOCATION, problem, oomph::DocInfo::set_directory(), TanhSolnForPoisson::source_function(), oomph::Global_string_for_annotation::string(), and TanhSolnForPoisson::TanPhi.