 Eigen  3.3.7 Eigen::IterativeSolverBase< Derived > Class Template Reference

## Detailed Description

### template<typename Derived> class Eigen::IterativeSolverBase< Derived >

Base class for linear iterative solvers.

class SimplicialCholesky, DiagonalPreconditioner, IdentityPreconditioner Inheritance diagram for Eigen::IterativeSolverBase< Derived >:

## Public Member Functions

template<typename MatrixDerived >
Derived & analyzePattern (const EigenBase< MatrixDerived > &A)

template<typename MatrixDerived >
Derived & compute (const EigenBase< MatrixDerived > &A)

RealScalar error () const

template<typename MatrixDerived >
Derived & factorize (const EigenBase< MatrixDerived > &A)

ComputationInfo info () const

Index iterations () const

IterativeSolverBase ()

template<typename MatrixDerived >
IterativeSolverBase (const EigenBase< MatrixDerived > &A)

Index maxIterations () const

Preconditioner & preconditioner ()

const Preconditioner & preconditioner () const

Derived & setMaxIterations (Index maxIters)

Derived & setTolerance (const RealScalar &tolerance)

template<typename Rhs , typename Guess >
const SolveWithGuess< Derived, Rhs, Guess > solveWithGuess (const MatrixBase< Rhs > &b, const Guess &x0) const

RealScalar tolerance () const Public Member Functions inherited from Eigen::SparseSolverBase< Derived >
template<typename Rhs >
const Solve< Derived, Rhs > solve (const MatrixBase< Rhs > &b) const

template<typename Rhs >
const Solve< Derived, Rhs > solve (const SparseMatrixBase< Rhs > &b) const

SparseSolverBase ()

## ◆ IterativeSolverBase() [1/2]

template<typename Derived>
 Eigen::IterativeSolverBase< Derived >::IterativeSolverBase ( )
inline

Default constructor.

## ◆ IterativeSolverBase() [2/2]

template<typename Derived>
template<typename MatrixDerived >
 Eigen::IterativeSolverBase< Derived >::IterativeSolverBase ( const EigenBase< MatrixDerived > & A )
inlineexplicit

Initialize the solver with matrix A for further `Ax=b` solving.

This constructor is a shortcut for the default constructor followed by a call to compute().

Warning
this class stores a reference to the matrix A as well as some precomputed values that depend on it. Therefore, if A is changed this class becomes invalid. Call compute() to update it with the new matrix A, or modify a copy of A.

## ◆ analyzePattern()

template<typename Derived>
template<typename MatrixDerived >
 Derived& Eigen::IterativeSolverBase< Derived >::analyzePattern ( const EigenBase< MatrixDerived > & A )
inline

Initializes the iterative solver for the sparsity pattern of the matrix A for further solving `Ax=b` problems.

Currently, this function mostly calls analyzePattern on the preconditioner. In the future we might, for instance, implement column reordering for faster matrix vector products.

## ◆ compute()

template<typename Derived>
template<typename MatrixDerived >
 Derived& Eigen::IterativeSolverBase< Derived >::compute ( const EigenBase< MatrixDerived > & A )
inline

Initializes the iterative solver with the matrix A for further solving `Ax=b` problems.

Currently, this function mostly initializes/computes the preconditioner. In the future we might, for instance, implement column reordering for faster matrix vector products.

Warning
this class stores a reference to the matrix A as well as some precomputed values that depend on it. Therefore, if A is changed this class becomes invalid. Call compute() to update it with the new matrix A, or modify a copy of A.

## ◆ error()

template<typename Derived>
 RealScalar Eigen::IterativeSolverBase< Derived >::error ( ) const
inline
Returns
the tolerance error reached during the last solve. It is a close approximation of the true relative residual error |Ax-b|/|b|.

## ◆ factorize()

template<typename Derived>
template<typename MatrixDerived >
 Derived& Eigen::IterativeSolverBase< Derived >::factorize ( const EigenBase< MatrixDerived > & A )
inline

Initializes the iterative solver with the numerical values of the matrix A for further solving `Ax=b` problems.

Currently, this function mostly calls factorize on the preconditioner.

Warning
this class stores a reference to the matrix A as well as some precomputed values that depend on it. Therefore, if A is changed this class becomes invalid. Call compute() to update it with the new matrix A, or modify a copy of A.

## ◆ info()

template<typename Derived>
 ComputationInfo Eigen::IterativeSolverBase< Derived >::info ( ) const
inline
Returns
Success if the iterations converged, and NoConvergence otherwise.

## ◆ iterations()

template<typename Derived>
 Index Eigen::IterativeSolverBase< Derived >::iterations ( ) const
inline
Returns
the number of iterations performed during the last solve

## ◆ maxIterations()

template<typename Derived>
 Index Eigen::IterativeSolverBase< Derived >::maxIterations ( ) const
inline
Returns
the max number of iterations. It is either the value setted by setMaxIterations or, by default, twice the number of columns of the matrix.

## ◆ preconditioner() [1/2]

template<typename Derived>
 Preconditioner& Eigen::IterativeSolverBase< Derived >::preconditioner ( )
inline
Returns
a read-write reference to the preconditioner for custom configuration.

## ◆ preconditioner() [2/2]

template<typename Derived>
 const Preconditioner& Eigen::IterativeSolverBase< Derived >::preconditioner ( ) const
inline
Returns
a read-only reference to the preconditioner.

## ◆ setMaxIterations()

template<typename Derived>
 Derived& Eigen::IterativeSolverBase< Derived >::setMaxIterations ( Index maxIters )
inline

Sets the max number of iterations. Default is twice the number of columns of the matrix.

## ◆ setTolerance()

template<typename Derived>
 Derived& Eigen::IterativeSolverBase< Derived >::setTolerance ( const RealScalar & tolerance )
inline

Sets the tolerance threshold used by the stopping criteria.

This value is used as an upper bound to the relative residual error: |Ax-b|/|b|. The default value is the machine precision given by NumTraits<Scalar>::epsilon()

## ◆ solveWithGuess()

template<typename Derived>
template<typename Rhs , typename Guess >
 const SolveWithGuess Eigen::IterativeSolverBase< Derived >::solveWithGuess ( const MatrixBase< Rhs > & b, const Guess & x0 ) const
inline
Returns
the solution x of using the current decomposition of A and x0 as an initial solution.