A temporary data structure for matrix in COO format. More...

#include <lf/assemble/coomatrix.h>

Public Types
using	Scalar = SCALAR

using	Triplet = Eigen::Triplet<SCALAR>

using	TripletVec = std::vector<Triplet>

using	Index = Eigen::Index

Public Member Functions
	COOMatrix (size_type num_rows, size_type num_cols)

	COOMatrix (const COOMatrix &)=default

	COOMatrix (COOMatrix &&) noexcept=default

COOMatrix &	operator= (const COOMatrix &)=default

COOMatrix &	operator= (COOMatrix &&) noexcept=default

	~COOMatrix ()=default

Index	rows () const
	return number of rows

Index	cols () const
	return number of column

void	AddToEntry (gdof_idx_t i, gdof_idx_t j, SCALAR increment)
	Add a value to the specified entry.

void	setZero ()
	Erase all entries of the matrix.

template<typename PREDICATE>
void	setZero (PREDICATE &&pred)
	Erase specific entries of the COO matrix, that is, set them to zero.

TripletVec &	triplets ()
	Gives access to the vector of triplets.

const TripletVec &	triplets () const

template<typename VECTOR>
Eigen::Matrix< SCALAR, Eigen::Dynamic, 1 >	MatVecMult (SCALAR alpha, const VECTOR &vec) const
	Computes the product of a (scaled) vector with the matrix in COO format.

template<typename VECTOR, typename RESULTVECTOR>
void	MatVecMult (SCALAR alpha, const VECTOR &vec, RESULTVECTOR &resvec) const
	In-situ computes the product of a vector with the matrix in COO format.

Eigen::SparseMatrix< Scalar >	makeSparse () const
	Create an Eigen::SparseMatrix out of the COO format.

Eigen::Matrix< Scalar, Eigen::Dynamic, Eigen::Dynamic >	makeDense () const
	Create an Eigen::MatrixX from the COO format.

void	PrintInfo (std::ostream &o) const
	Ouput of triplet list describing COO matrix.

Private Attributes
size_type	rows_

size_type	cols_

TripletVec	triplets_ {}

Friends
template<typename SCALARTYPE>
std::ostream &	operator<< (std::ostream &o, const COOMatrix< SCALARTYPE > &mat)
	Output operator for COO matrix.

Detailed Description

template<typename SCALAR>
class lf::assemble::COOMatrix< SCALAR >

A temporary data structure for matrix in COO format.

Template Parameters

SCALAR basic scalar type for the matrix

This class provides a container for a matrix in triplet format, also known as COO format see Wikipedia. It essentially manages a vector of Eigen triplets_.

This matrix format allows efficient incremental matrix construction in the context of local assembly.

type requirements for template arguments

SCALAR must be a type that can serve as a scalar type for Eigen::Matrix.

Warning: Objects of this type are no matrix objects in the sense of Eigen. This means you cannot use them instead of an Eigen matrix type, but you have to convert them into a sparse Eigen matrix before by calling COOMatrix::makeSparse().

sample usage:

  // Obtain a shared pointed to a mesh
  std::shared_ptr<lf::mesh::Mesh> mesh_p{
      lf::mesh::test_utils::GenerateHybrid2DTestMesh(0)};
  // Initialization of index mapping for linear finite elements
  lf::assemble::UniformFEDofHandler loc_glob_map(
      mesh_p, {{lf::base::RefEl::kPoint(), 1}});
  // Initialize ENTITYMATRIXPROVIDER object for local computations
  lf::uscalfe::LinearFELaplaceElementMatrix loc_mat_laplace{};
  // Dimension of finite element space
  const lf::assemble::size_type N_dofs(loc_glob_map.NumDofs());
  // Matrix in triplet format holding Galerkin matrix
  lf::assemble::COOMatrix<double> mat(N_dofs, N_dofs);
  // Building the Galerkin matrix (trial space = test space)
  lf::assemble::AssembleMatrixLocally<lf::assemble::COOMatrix<double>>(
      0, loc_glob_map, loc_glob_map, loc_mat_laplace, mat);
  // the `mat` object now contains the Galerkin matrix in triplet/COO format
  // Initialize an Eigen sparse matrix object from `mat`
  Eigen::SparseMatrix<double> stiffness_matrix = {mat.makeSparse()};

Definition at line 52 of file coomatrix.h.

Member Typedef Documentation

◆ Index

template<typename SCALAR>

using lf::assemble::COOMatrix< SCALAR >::Index = Eigen::Index

Definition at line 57 of file coomatrix.h.

◆ Scalar

template<typename SCALAR>

using lf::assemble::COOMatrix< SCALAR >::Scalar = SCALAR

Definition at line 54 of file coomatrix.h.

◆ Triplet

template<typename SCALAR>

using lf::assemble::COOMatrix< SCALAR >::Triplet = Eigen::Triplet<SCALAR>

Definition at line 55 of file coomatrix.h.

◆ TripletVec

template<typename SCALAR>

using lf::assemble::COOMatrix< SCALAR >::TripletVec = std::vector<Triplet>

Definition at line 56 of file coomatrix.h.

Constructor & Destructor Documentation

◆ COOMatrix() [1/3]

template<typename SCALAR>

lf::assemble::COOMatrix< SCALAR >::COOMatrix	(	size_type	num_rows,
		size_type	num_cols )

inline

Set up zero matrix of a given size

Definition at line 60 of file coomatrix.h.

References cols_, and rows_.

Referenced by COOMatrix(), COOMatrix(), operator<<, operator=(), operator=(), and ~COOMatrix().

◆ COOMatrix() [2/3]

template<typename SCALAR>

lf::assemble::COOMatrix< SCALAR >::COOMatrix ( const COOMatrix< SCALAR > & )

default

References COOMatrix().

◆ COOMatrix() [3/3]

template<typename SCALAR>

lf::assemble::COOMatrix< SCALAR >::COOMatrix ( COOMatrix< SCALAR > && )

defaultnoexcept

References COOMatrix().

◆ ~COOMatrix()

template<typename SCALAR>

lf::assemble::COOMatrix< SCALAR >::~COOMatrix ( )

default

References COOMatrix().

Member Function Documentation

◆ AddToEntry()

template<typename SCALAR>

void lf::assemble::COOMatrix< SCALAR >::AddToEntry	(	gdof_idx_t	i,
		gdof_idx_t	j,
		SCALAR	increment )

inline

Add a value to the specified entry.

Parameters

i	row index
j	column index
increment

Adds another index-value triplet.

Note: the size information for the matrix is adjusted to the passed indices. This ensures that the internally stored numbers of columns and rows are always bigger than the indices of any triplet. When manipulating the triplet information directly, one has to make sure that the size information remains valid.

Definition at line 87 of file coomatrix.h.

References cols_, rows_, and triplets_.

Referenced by lf::assemble::FixFlaggedSolutionCompAlt(), and lf::assemble::FixFlaggedSolutionComponents().

◆ cols()

template<typename SCALAR>

Index lf::assemble::COOMatrix< SCALAR >::cols ( ) const

inlinenodiscard

return number of column

Definition at line 72 of file coomatrix.h.

References cols_.

Referenced by lf::assemble::FixFlaggedSolutionCompAlt(), lf::assemble::FixFlaggedSolutionComponents(), and lf::assemble::FixSolutionComponentsLse().

◆ makeDense()

template<typename SCALAR>

Eigen::Matrix< Scalar, Eigen::Dynamic, Eigen::Dynamic > lf::assemble::COOMatrix< SCALAR >::makeDense ( ) const

inlinenodiscard

Create an Eigen::MatrixX from the COO format.

Returns: A dense matrix representing the COO matrix

This method is mainly meant for debugging

Definition at line 188 of file coomatrix.h.

References cols_, rows_, and triplets_.

◆ makeSparse()

template<typename SCALAR>

Eigen::SparseMatrix< Scalar > lf::assemble::COOMatrix< SCALAR >::makeSparse ( ) const

inlinenodiscard

Create an Eigen::SparseMatrix out of the COO format.

Returns: The created sparse matrix

Note: This method can be called multiple times and it does not modify the data stored in this COOMatrix.

Definition at line 172 of file coomatrix.h.

References cols_, rows_, and triplets_.

◆ MatVecMult() [1/2]

template<typename SCALAR>

template<typename VECTOR>

Eigen::Matrix< SCALAR, Eigen::Dynamic, 1 > lf::assemble::COOMatrix< SCALAR >::MatVecMult	(	SCALAR	alpha,
		const VECTOR &	vec ) const

nodiscard

Computes the product of a (scaled) vector with the matrix in COO format.

Template Parameters

VECTOR a basic vector type for the argument vector

Parameters

alpha	scalar with which to multiply the argument vector before the matrix x vector multiplication.
vec	constant reference to a vector of type VECTOR

Returns: result vector, a dense vector of Eigen

Requirements for type VECTOR

An object of type VECTOR must provide a method Size() telling the length of the vector and operator [] for read access to vector entries.

Definition at line 236 of file coomatrix.h.

References cols_, rows_, and triplets_.

Referenced by lf::assemble::FixFlaggedSolutionComponents().

◆ MatVecMult() [2/2]

template<typename SCALAR>

template<typename VECTOR, typename RESULTVECTOR>

void lf::assemble::COOMatrix< SCALAR >::MatVecMult	(	SCALAR	alpha,
		const VECTOR &	vec,
		RESULTVECTOR &	resvec ) const

In-situ computes the product of a vector with the matrix in COO format.

Template Parameters

VECTOR	a basic vector type for the argument vector
RESULTVECTOR	another vector type for returning the result

Parameters

alpha	scalar with which to multiply the argument vector before the matrix x vector multiplication.
vec	constant reference to a vector of type VECTOR
resvec	reference to an object of type RESULTVECTOR.

Note: the result of the matrix-vector product will be added to the entries of result!

Requirements for types VECTOR and RESULTVECTOR

An object of type VECTOR or RESULTVECTOR must provide a method Size() telling the length of the vector and operator [] for read/write access to vector entries.

Definition at line 250 of file coomatrix.h.

References cols_, rows_, and triplets_.

◆ operator=() [1/2]

template<typename SCALAR>

COOMatrix & lf::assemble::COOMatrix< SCALAR >::operator= ( const COOMatrix< SCALAR > & )

default

References COOMatrix().

◆ operator=() [2/2]

template<typename SCALAR>

COOMatrix & lf::assemble::COOMatrix< SCALAR >::operator= ( COOMatrix< SCALAR > && )

defaultnoexcept

References COOMatrix().

◆ PrintInfo()

template<typename SCALAR>

void lf::assemble::COOMatrix< SCALAR >::PrintInfo ( std::ostream & o ) const

inline

Ouput of triplet list describing COO matrix.

Parameters

o	output stream

Definition at line 205 of file coomatrix.h.

References cols_, rows_, and triplets_.

Referenced by operator<<.

◆ rows()

template<typename SCALAR>

Index lf::assemble::COOMatrix< SCALAR >::rows ( ) const

inlinenodiscard

return number of rows

Definition at line 70 of file coomatrix.h.

References rows(), and rows_.

Referenced by lf::assemble::FixFlaggedSolutionCompAlt(), lf::assemble::FixFlaggedSolutionComponents(), lf::assemble::FixSolutionComponentsLse(), and rows().

◆ setZero() [1/2]

template<typename SCALAR>

void lf::assemble::COOMatrix< SCALAR >::setZero ( )

inline

Erase all entries of the matrix.

This method clears the vector of triplets, effectively setting the matrix to zero. It does not affect the size information about the matrix.

Definition at line 98 of file coomatrix.h.

References triplets_.

Referenced by lf::assemble::FixFlaggedSolutionCompAlt(), and lf::assemble::FixFlaggedSolutionComponents().

◆ setZero() [2/2]

template<typename SCALAR>

template<typename PREDICATE>

void lf::assemble::COOMatrix< SCALAR >::setZero ( PREDICATE && pred )

inline

Erase specific entries of the COO matrix, that is, set them to zero.

Template Parameters

PREDICATE a predicate type compliant with std::function<bool(gdof_idx_t,gdof_idx_t)>

Parameters

pred	selector predicate

Removes all triplets trp for which pred(trp.row(),trp.col()) is true. This amounts to setting the corresponding matrix entries to zero.

Definition at line 109 of file coomatrix.h.

References triplets_.

◆ triplets() [1/2]

template<typename SCALAR>

TripletVec & lf::assemble::COOMatrix< SCALAR >::triplets ( )

inlinenodiscard

Gives access to the vector of triplets.

Returns: reference to internal vector of triplets

Use of this method is deprecated. Use setZero(pred) and AddToEntry() instead.

Definition at line 124 of file coomatrix.h.

References triplets_.

◆ triplets() [2/2]

template<typename SCALAR>

const TripletVec & lf::assemble::COOMatrix< SCALAR >::triplets ( ) const

inlinenodiscard

Definition at line 125 of file coomatrix.h.

References triplets_.

Friends And Related Symbol Documentation

◆ operator<<

template<typename SCALAR>

template<typename SCALARTYPE>

std::ostream & operator<<	(	std::ostream &	o,
		const COOMatrix< SCALARTYPE > &	mat )

friend

Output operator for COO matrix.

This function prints matrix size and the list of triplets

Definition at line 229 of file coomatrix.h.

References COOMatrix(), and PrintInfo().

Member Data Documentation

◆ cols_

template<typename SCALAR>

size_type lf::assemble::COOMatrix< SCALAR >::cols_

private

dimensions of matrix

Definition at line 223 of file coomatrix.h.

Referenced by AddToEntry(), cols(), COOMatrix(), makeDense(), makeSparse(), MatVecMult(), MatVecMult(), and PrintInfo().

◆ rows_

template<typename SCALAR>

size_type lf::assemble::COOMatrix< SCALAR >::rows_

private

Definition at line 223 of file coomatrix.h.

Referenced by AddToEntry(), COOMatrix(), makeDense(), makeSparse(), MatVecMult(), MatVecMult(), PrintInfo(), and rows().

◆ triplets_

template<typename SCALAR>

TripletVec lf::assemble::COOMatrix< SCALAR >::triplets_ {}

private

COO format data

Definition at line 224 of file coomatrix.h.

Referenced by AddToEntry(), makeDense(), makeSparse(), MatVecMult(), MatVecMult(), PrintInfo(), setZero(), setZero(), triplets(), and triplets().

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

/home/runner/work/lehrfempp/lehrfempp/lib/lf/assemble/coomatrix.h

Public Types

Public Member Functions

Private Attributes

Friends

Detailed Description

type requirements for template arguments

sample usage:

Member Typedef Documentation

◆ Index

◆ Scalar

◆ Triplet

◆ TripletVec

Constructor & Destructor Documentation

◆ COOMatrix() [1/3]

◆ COOMatrix() [2/3]

◆ COOMatrix() [3/3]

◆ ~COOMatrix()

Member Function Documentation

◆ AddToEntry()

◆ cols()

◆ makeDense()

◆ makeSparse()

◆ MatVecMult() [1/2]

Requirements for type VECTOR

◆ MatVecMult() [2/2]

Requirements for types VECTOR and RESULTVECTOR

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ PrintInfo()

◆ rows()

◆ setZero() [1/2]

◆ setZero() [2/2]

◆ triplets() [1/2]

◆ triplets() [2/2]

Friends And Related Symbol Documentation

◆ operator<<

Member Data Documentation

◆ cols_

◆ rows_

◆ triplets_