Computes the magnetic field \(\vec{B}\) as a curl of the magnetic vector potential, \(\vec{A}\), i.e., \(\vec{B} = \vec{\nabla} \times \vec{A}\). More...

#include <project_A_to_B.hpp>

Inheritance diagram for StaticVectorSolver::ProjectAtoB< stage >:

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Collaboration diagram for StaticVectorSolver::ProjectAtoB< stage >:

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Public Member Functions
	ProjectAtoB (unsigned int p, unsigned int mapping_degree, const Triangulation< 3 > &triangulation_A, const DoFHandler< 3 > &dof_handler_A, const Vector< double > &solution_A, std::string fname="B", const Function< 3 > *exact_solution=nullptr, bool print_time_tables=false, bool project_exact_solution=false, bool log_cg_convergence=false, bool write_higher_order_cells=false)
	The only constructor. More...

Public Member Functions inherited from StaticVectorSolver::ProjectHcurlToHdiv< 1 >
	ProjectHcurlToHdiv (unsigned int p, unsigned int mapping_degree, const Triangulation< 3 > &triangulation_Hcurl, const DoFHandler< 3 > &dof_handler_Hcurl, const Vector< double > &solution_Hcurl, std::string fname="Hdiv", const Function< 3 > *exact_solution=nullptr, bool print_time_tables=false, bool project_exact_solution=false, bool log_cg_convergence=false, bool write_higher_order_cells=false)
	The only constructor. More...

double	get_L2_norm ()
	Returns \(L^2\) error norm.

double	get_Linfty_norm ()
	Returns \(L^{\infty}\) error norm.

unsigned int	get_n_cells () const
	Returns the number of active cells in the mesh.

unsigned int	get_n_dofs () const
	Returns the total amount of the degrees of freedom.

void	clear ()
	Releases computer memory associated with system matrix and right-hand side.

const Triangulation< 3 > &	get_tria () const
	Returns a reference to triangulation.

const DoFHandler< 3 > &	get_dof_handler () const
	Returns a reference to dof handler associated with the Raviart-Thomas finite elements.

const Vector< double > &	get_solution () const
	Returns a reference to solution, i.e., the result of the projection.

void	save_matrix_and_rhs_to_csv (std::string fname) const
	Saves the system matrix and the right-hand side into a csv file. More...

Detailed Description

template<int stage = 1>
class StaticVectorSolver::ProjectAtoB< stage >

Computes the magnetic field \(\vec{B}\) as a curl of the magnetic vector potential, \(\vec{A}\), i.e., \(\vec{B} = \vec{\nabla} \times \vec{A}\).

The problem is assumed to be three-dimensional. This class template is meant to be used in conjunction with StaticVectorSolver::Solver1 or StaticVectorSolver::Solver2.

The magnetic vector potential, \(\vec{A}\), is assumed to be an output of an object of the class StaticVectorSolver::Solver1 or StaticVectorSolver::Solver2 . That is, \(\vec{A}\) is expressed as a linear combination of the shape functions of the FE_Nedelec finite elements. In other words, \(\vec{A}\) is in the \(H(\text{curl})\) function space. This class template computes magnetic field \(\vec{B}\) as a curl of the magnetic vector potential, \(\vec{A}\), such that \(\vec{B}\) is expressed as a linear combination of the shape functions of the FE_RaviartThomas finite elements. That is, \(\vec{B}\) is in the \(H(\text{div})\) function space. In other words, this class template takes a vector field \(\vec{A}\) from the \(H(\text{curl})\) function space, calculates its curl, and projects the result into \(H(\text{div})\) function space, which is a proper space for the magnetic field \(\vec{B}\). The operation of projection is illustrated by means of the Bossavit's diagram below.

It is assumed that the object of the class StaticVectorSolver::Solver1 or StaticVectorSolver::Solver2 that yielded \(\vec{A}\) is still in the computer memory such that the triangulation, the degrees of freedom, and the handler of the degrees of freedom are accessible while \(\vec{B}\) is computed. An object of the StaticVectorSolver::ProjectAtoB class template reuses the triangulation by creating an additional dof handler associated with the FE_RaviartThomas finite elements. That is, \(\vec{A}\) and \(\vec{B}\) share the same triangulation but are modeled by different finite elements: \(\vec{A}\) - by FE_Nedelec and \(\vec{B}\) - by FE_RaviartThomas. In this disposition there are two DoFHandler objects associated with one Triangulation object. The algorithm walks synchronously through both DoFHandler objects and assembles the system matrix and the right-hand side.

The algorithm utilizes the WorkStream technology of deal.II. The amount of threads used can be limited as the following.

#include <deal.II/base/multithread_info.h>
 
MultithreadInfo::set_thread_limit(nr_threads_max);

The output data are saved into a vtk file. The following data are saved:

The calculated magnetic field, \(\vec{B} = \vec{\nabla} \times \vec{A}\), under the name "VectorField".
The \(L^2\) and \(L^{\infty}\) error norms associated with the calculated magnetic field under the names "L2norm" and "LinftyNorm". One value per mesh cell is saved.
The exact solution projected onto \(H(\text{div})\) function space is saved under the name "VectorFieldExact". The "VectorField" and "VectorFieldExact" are modeled by exactly the same finite elements, i.e., FE_RaviartThomas.

The "L2norm", "LinftyNorm", and "VectorFieldExact" are saved only if an exact solution is passed to the constructor. Moreover, "VectorFieldExact" is calculated and saved only if the input parameter project_exact_solution passed to the constructor equals true.

The user is supposed to derive an object from this class template. All usual computations, i.e., setup, assembling the linear system, etc., happen automatically.

Note: Application examples:

mms-v/, mms-vt-i/, ssol-i/, ssol-ii/, ssol-iii/.

Definition at line 106 of file project_A_to_B.hpp.

Constructor & Destructor Documentation

◆ ProjectAtoB()

template<int stage = 1>

StaticVectorSolver::ProjectAtoB< stage >::ProjectAtoB	(	unsigned int	p,
		unsigned int	mapping_degree,
		const Triangulation< 3 > &	triangulation_A,
		const DoFHandler< 3 > &	dof_handler_A,
		const Vector< double > &	solution_A,
		std::string	fname = `"B"`,
		const Function< 3 > *	exact_solution = `nullptr`,
		bool	print_time_tables = `false`,
		bool	project_exact_solution = `false`,
		bool	log_cg_convergence = `false`,
		bool	write_higher_order_cells = `false`
	)

inline

The only constructor.

Constructs the object and runs the calculations. That is, there is no need to call other functions such as run().

Parameters

[in]	p	- The degree of the FE_RaviartThomas finite elements.
[in]	mapping_degree	- The degree of the interpolating polynomials used for mapping. Setting it to 1 will do in the most of the cases. Note, that it makes sense to attach a meaningful manifold to the triangulation if this parameter is greater than 1.
[in]	triangulation_A	- Reference to the triangulation inside an object of the class StaticVectorSolver::Solver1 or StaticVectorSolver::Solver2 that has yielded the magnetic vector potential, \(\vec{A}\).
[in]	dof_handler_A	- Reference to the dof handler inside the class StaticVectorSolver::Solver1 or StaticVectorSolver::Solver2 that has yielded the magnetic vector potential, \(\vec{A}\).
[in]	solution_A	- Vector filled with the degrees of freedom that together with the shape functions of the FE_Nedelec finite elements model the magnetic vector potential, \(\vec{A}\).
[in]	fname	- The name of the output files without extension.
[in]	exact_solution	- Points to an object that describes the exact solution to the problem. It is needed for calculating error norms. The exact solution object must exist in the computer memory at the time of calling this constructor.
[in]	print_time_tables	- If true, prints time tables on the screen.
[in]	project_exact_solution	- If true, projects the exact solution onto the space spanned by the FE_Nedelec finite elements and saves the result into the output file next to \(\vec{B}\).
[in]	log_cg_convergence	- If true, logs convergence of the conjugate gradient solver into a file. The name of the file is generated by appending "_cg_convergence.csv" to fname.
[in]	write_higher_order_cells	- If false, the data is saved in the file fname.vtk. Higher-order cells are not saved. If true, the data is saved into fname.vtu file preserving the higher-order cells. In this case the file can be viewed with a help of Paraview version 5.5.0 or higher.

Definition at line 153 of file project_A_to_B.hpp.

The documentation for this class was generated from the following file:

static/shared/include/project_A_to_B.hpp

Public Member Functions

Detailed Description

template<int stage = 1> class StaticVectorSolver::ProjectAtoB< stage >

Constructor & Destructor Documentation

◆ ProjectAtoB()

template<int stage = 1>
class StaticVectorSolver::ProjectAtoB< stage >