Please, help us to better know about our user community by answering the following short survey: https://forms.gle/wpyrxWi18ox9Z5ae9 Eigen  3.3.71 Eigen::SimplicialLDLT Class Reference

## Detailed Description

A direct sparse LDLT Cholesky factorizations without square root.

This class provides a LDL^T Cholesky factorizations without square root of sparse matrices that are selfadjoint and positive definite. The factorization allows for solving A.X = B where X and B can be either dense or sparse.

In order to reduce the fill-in, a symmetric permutation P is applied prior to the factorization such that the factorized matrix is P A P^-1.

Template Parameters
 _MatrixType the type of the sparse matrix A, it must be a SparseMatrix<> _UpLo the triangular part that will be used for the computations. It can be Lower or Upper. Default is Lower. _Ordering The ordering method to use, either AMDOrdering<> or NaturalOrdering<>. Default is AMDOrdering<>

This class follows the sparse solver concept .

class SimplicialLLT, class AMDOrdering, class NaturalOrdering

## Public Member Functions

void analyzePattern (const MatrixType &a)

SimplicialLDLTcompute (const MatrixType &matrix)

Scalar determinant () const

void factorize (const MatrixType &a)

const MatrixL matrixL () const

const MatrixU matrixU () const

SimplicialLDLT ()

SimplicialLDLT (const MatrixType &matrix)

const VectorType vectorD () const

## ◆ SimplicialLDLT() [1/2]

 Eigen::SimplicialLDLT::SimplicialLDLT ( )
inline

Default constructor

## ◆ SimplicialLDLT() [2/2]

 Eigen::SimplicialLDLT::SimplicialLDLT ( const MatrixType & matrix )
inlineexplicit

Constructs and performs the LLT factorization of matrix

## ◆ analyzePattern()

 void Eigen::SimplicialLDLT::analyzePattern ( const MatrixType & a )
inline

Performs a symbolic decomposition on the sparcity of matrix.

This function is particularly useful when solving for several problems having the same structure.

factorize()

## ◆ compute()

 SimplicialLDLT& Eigen::SimplicialLDLT::compute ( const MatrixType & matrix )
inline

Computes the sparse Cholesky decomposition of matrix

## ◆ determinant()

 Scalar Eigen::SimplicialLDLT::determinant ( ) const
inline
Returns
the determinant of the underlying matrix from the current factorization

## ◆ factorize()

 void Eigen::SimplicialLDLT::factorize ( const MatrixType & a )
inline

Performs a numeric decomposition of matrix

The given matrix must has the same sparcity than the matrix on which the symbolic decomposition has been performed.

analyzePattern()

## ◆ matrixL()

 const MatrixL Eigen::SimplicialLDLT::matrixL ( ) const
inline
Returns
an expression of the factor L

## ◆ matrixU()

 const MatrixU Eigen::SimplicialLDLT::matrixU ( ) const
inline
Returns
an expression of the factor U (= L^*)

## ◆ vectorD()

 const VectorType Eigen::SimplicialLDLT::vectorD ( ) const
inline
Returns
a vector expression of the diagonal D

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