Kaskade::MultiGridStack< Prolongation, Entry, Index > Class Template Reference

Class for multigrid stacks. More...

#include <prolongation.hh>

Detailed Description

template<class Prolongation, class Entry, class Index>
class Kaskade::MultiGridStack< Prolongation, Entry, Index >

Class for multigrid stacks.

This provides the storage of and access to prolongations and projected Galerkin matrices, but leaves the construction of these to derived classes.

Definition at line 747 of file prolongation.hh.

Public Member Functions
	MultiGridStack (std::vector< Prolongation > &&ps, std::vector< NumaBCRSMatrix< Entry, Index > > &&as)
	Constructor. More...
	MultiGridStack (std::vector< Prolongation > &&ps, NumaBCRSMatrix< Entry, Index > &&A, bool onlyLowerTriangle)
	Constructor. More...
	MultiGridStack (MultiGridStack &&other)=default
int	levels () const
	The number of grid levels. More...
Prolongation const &	p (int level) const
	Returns the prolongation from given level to next higher one. More...
NumaBCRSMatrix< Entry, Index > const &	a (int level) const
	Returns the projected Galerkin matrix on the given level. More...
NumaBCRSMatrix< Entry, Index > &	coarseGridMatrix ()
	Returns the projected Galerkin matrix on the coarsest level. More...
void	report (std::ostream &out) const

Related Functions
(Note that these are not member functions.)
template<class Prolongation , class Entry , class Index >
MultiGridStack< Prolongation, Entry, Index >	makeMultiGridStack (std::vector< Prolongation > &&ps, NumaBCRSMatrix< Entry, Index > &&A, bool onlyLowerTriangle)
	Convenience routine for creating multigrid stacks. More...

Constructor & Destructor Documentation

MultiGridStack() [1/3]

template<class Prolongation , class Entry , class Index >

Kaskade::MultiGridStack< Prolongation, Entry, Index >::MultiGridStack ( std::vector< Prolongation > &&  ps, std::vector< NumaBCRSMatrix< Entry, Index > > &&  as  )

inline

Constructor.

This takes both a stack of prolongations and a matching stack of projected.

Parameters

ps	a stack of prolongations
as	a stack of stiffness matrices. as.size()==ps.size()+1 has to hold.

Usually, it holds that \( A_i = P_i^T A_{i+1} P_i \), i.e. as[0] contains the coarse grid matrix.

Definition at line 760 of file prolongation.hh.

MultiGridStack() [2/3]

template<class Prolongation , class Entry , class Index >

Kaskade::MultiGridStack< Prolongation, Entry, Index >::MultiGridStack ( std::vector< Prolongation > &&  ps, NumaBCRSMatrix< Entry, Index > &&  A, bool  onlyLowerTriangle  )

inline

Constructor.

This takes a stack of prolongations and creates the stack of projected Galerkin matrices from the given fine grid matrix. Most useful for geometric multigrid, where the prolongations are defined solely in terms of the grid.

See also

makeMultiGridStack

Definition at line 774 of file prolongation.hh.

MultiGridStack() [3/3]

template<class Prolongation , class Entry , class Index >

Kaskade::MultiGridStack< Prolongation, Entry, Index >::MultiGridStack ( MultiGridStack< Prolongation, Entry, Index > &&  other )

default

Member Function Documentation

a()

template<class Prolongation , class Entry , class Index >

NumaBCRSMatrix< Entry, Index > const & Kaskade::MultiGridStack< Prolongation, Entry, Index >::a ( int  level ) const

inline

Returns the projected Galerkin matrix on the given level.

Parameters

level

precondition 0 <= level < levels()

For level==0, the returned matrix can be in an undefined state if it has been modified previously via the non-const coarseGridMatrix() reference.

Definition at line 819 of file prolongation.hh.

Referenced by Kaskade::MultiGridStack< Prolongation, Entry, Index >::report().

coarseGridMatrix()

template<class Prolongation , class Entry , class Index >

NumaBCRSMatrix< Entry, Index > & Kaskade::MultiGridStack< Prolongation, Entry, Index >::coarseGridMatrix ( )

inline

Returns the projected Galerkin matrix on the coarsest level.

This is explicitly a mutable reference, such that the coarse grid matrix can be moved from. This is useful, as in the multigrid, the coarsest level matrix is not referenced (the coarse grid preconditioner has its own copy, maybe obtained by moving from here...):

auto coarseSolver = makeDirectPreconditioner(std::move(mgStack.coarseGridMatrix()));

Definition at line 835 of file prolongation.hh.

levels()

template<class Prolongation , class Entry , class Index >

int Kaskade::MultiGridStack< Prolongation, Entry, Index >::levels ( ) const

inline

The number of grid levels.

Definition at line 796 of file prolongation.hh.

Referenced by Kaskade::MultiGridStack< Prolongation, Entry, Index >::a(), and Kaskade::MultiGridStack< Prolongation, Entry, Index >::p().

p()

template<class Prolongation , class Entry , class Index >

Prolongation const & Kaskade::MultiGridStack< Prolongation, Entry, Index >::p ( int  level ) const

inline

Returns the prolongation from given level to next higher one.

Parameters

level

precondition 0 <= level < levels()-1

Definition at line 805 of file prolongation.hh.

Referenced by Kaskade::MultiGridStack< Prolongation, Entry, Index >::report().

report()

template<class Prolongation , class Entry , class Index >

void Kaskade::MultiGridStack< Prolongation, Entry, Index >::report ( std::ostream &  out ) const

inline

Definition at line 840 of file prolongation.hh.

Referenced by Kaskade::operator<<().

---

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

• prolongation.hh