cig_load_input_data.cc

We will load the CIG input data from here into a C++ code. The input data was created with the Concepts Input Generator (CIG). See Concepts tutorials for more tutorials.

Introduction

In a previous tutorial we generated a cig-file, which contains several paramters and five dat-files, which contain information about the mesh. Now we are going to show, how to access this information from C++.

Commented Program

First, we initialize input and make it contain all the parameters from the CIG input data.

    concepts::InOutParameters input;
 
    concepts::ProcessParameter parameter(input);
    
    std::cout << "Parameters have been processed" << std::endl;
    
    if (!parameter.apply(argc, argv))
      exit(1);

Now we can access all the parameters by appropriate getter-methods and by the respective names, which we specified in the Python code used for generating the input data.

    std::cout << "Some string  : " << input.getString("some_string") << std::endl;
    std::cout << "Some float   : " << input.getDouble("some_float") << std::endl;
    std::cout << "Some int     : " << input.getInt("some_int") << std::endl;
    std::cout << "Some boolean : " << input.getBool("some_boolean") << std::endl;

Concepts provides methods to create meshes from given dat-files.

    std::unique_ptr<concepts::Mesh2> mesh(concepts::import2dMeshGeneralFromInput(input, false));    

Finally, we create a space with certain refinement strategies, which are contained in input.

    hp2D::hpAdaptiveSpaceH1 space(*mesh,input);

Supposing that your compiled program is named cig_load_input_data, the code is executed with the command

./cig_load_input_data -f cig_input_demo.cig

If nothing went wrong, you should get the following output in the terminal:

Some string  : Live long and prosper!
Some float   : 3.14159
Some int     : 42
Some boolean : 1
Mesh: concepts::Import2dMeshGeneral(ncell = 1)
Space: hp2D::hpAdaptiveSpaceH1(dim = 286 (V:18, E:102, I:166), nelm = 13)

and there should be two eps-files showing the defined mesh in the from the input data and the hp-refined mesh.

Plot of the initial mesh:

Plot of the refined mesh:

Complete Source Code

#include <iostream>
#include "geometry.hh"
#include "graphics.hh"
#include "hp2D.hh"
#include "space.hh"
 
 
int main(int argc, char** argv) {
 
  try {
 
    concepts::InOutParameters input;
 
    concepts::ProcessParameter parameter(input);
    
    std::cout << "Parameters have been processed" << std::endl;
    
    if (!parameter.apply(argc, argv))
      exit(1);
 
    std::cout << "Some string  : " << input.getString("some_string") << std::endl;
    std::cout << "Some float   : " << input.getDouble("some_float") << std::endl;
    std::cout << "Some int     : " << input.getInt("some_int") << std::endl;
    std::cout << "Some boolean : " << input.getBool("some_boolean") << std::endl;
 
    std::unique_ptr<concepts::Mesh2> mesh(concepts::import2dMeshGeneralFromInput(input, false));    
    std::cout << "Mesh: " << *mesh << std::endl;
    graphics::drawMeshEPS( *mesh, input.getString("some_project_name") + "_mesh.eps", 100, 1.0, 100);
 
    hp2D::hpAdaptiveSpaceH1 space(*mesh,input);
    space.rebuild();
    std::cout << "Space: " << space << std::endl;
    graphics::drawMeshEPS(space, input.getString("some_project_name") + "_space.eps",100,1.0,20);
    
  }
  catch (concepts::ExceptionBase& e) {
    std::cout << e << std::endl;
    return 1;
  }
  return 0;
}