Nonowning view of a set of degrees of freedom corresponding to a mesh point in a block vector or multivector. More...

#include <Tpetra_Experimental_BlockView.hpp>

Public Member Functions
	LittleVector (Scalar *const A, const LO blockSize, const LO stride)
	Constructor. More...

template<class T >
	LittleVector (T const A, const LO blockSize, const LO stride, typename std::enable_if< !std::is_same< Scalar, T >::value &&std::is_convertible< Scalar, T >::value &&sizeof(Scalar)==sizeof(T), int >::type ignoreMe=NULL)
	Constructor that takes an `impl_scalar_type` pointer. More...

Scalar *	getRawPtr () const
	Pointer to the block's entries. More...

LO	getBlockSize () const
	The block size (number of degrees of freedom per mesh point). More...

LO	getStride () const
	Stride between consecutive entries. More...

impl_scalar_type &	operator() (const LO i) const
	Reference to entry (i) of the vector. More...

template<class LittleVectorType >
void	update (const Scalar &alpha, const LittleVectorType &X) const
	`this := this + alpha * X`. More...

template<class LittleVectorType >
void	assign (const LittleVectorType &X) const
	`*this := X`. More...

void	scale (const Scalar &alpha) const
	`(this)(i,j) := alpha (*this)(i,j)` for all (i,j). More...

void	fill (const Scalar &alpha) const
	`(*this)(i,j) := alpha` for all (i,j). More...

template<class LittleVectorType >
void	absmax (const LittleVectorType &X) const
	`(this)(i,j) := max(abs((this)(i,j)), abs(X(i,j)))` for all (i,j). More...

template<class LittleVectorType >
bool	equal (const LittleVectorType &X) const
	true if and only if all entries of this equal all entries of X. More...

template<class LittleBlockType , class LittleVectorType >
void	matvecUpdate (const Scalar &alpha, const LittleBlockType &A, const LittleVectorType &X) const
	`(this) := (this) + alpha * A * X` (matrix-vector multiply). More...

Detailed Description

template<class Scalar, class LO>
class Tpetra::Experimental::LittleVector< Scalar, LO >

Nonowning view of a set of degrees of freedom corresponding to a mesh point in a block vector or multivector.

Template Parameters

Scalar	The type of entries.
LO	The type of local indices. See the documentation of the first template parameter of Map for requirements.

"Little" means local (not distributed over multiple MPI processes; stored to maximize locality) and small (think length 3, not length 1000).

The Scalar template parameter may be const or nonconst. This is one reason why instance methods below that take a LittleVector accept it as a template parameter: that lets you add a const LittleVector (e.g., LittleVector<const double, int>) to a nonconst LittleVector (e.g., LittleVector<double, int>).

Definition at line 325 of file Tpetra_Experimental_BlockView.hpp.

Constructor & Destructor Documentation

template<class Scalar , class LO >

Tpetra::Experimental::LittleVector< Scalar, LO >::LittleVector	(	Scalar *const	A,
		const LO	blockSize,
		const LO	stride
	)

inline

Constructor.

Parameters

A	[in] Pointer to the vector's entries
blockSize	[in] Dimension of the vector
stride	[in] Stride between consecutive entries

Definition at line 338 of file Tpetra_Experimental_BlockView.hpp.

template<class Scalar , class LO >

template<class T >

Tpetra::Experimental::LittleVector< Scalar, LO >::LittleVector	(	T *const	A,
		const LO	blockSize,
		const LO	stride,
		typename std::enable_if< !std::is_same< Scalar, T >::value &&std::is_convertible< Scalar, T >::value &&sizeof(Scalar)==sizeof(T), int * >::type	ignoreMe = `NULL`
	)

inline

Constructor that takes an impl_scalar_type pointer.

Parameters

A	[in] Pointer to the vector's entries, as `impl_scalar_type` rather than `Scalar`
blockSize	[in] Dimension of the vector
stride	[in] Stride between consecutive entries

While this constructor is templated on a type T, the intent is that T == impl_scalar_type. (We must template on T rather than using impl_scalar_type directly, because of how std::enable_if works.) The long, complicated std::enable_if expression ensures that this constructor only exists if Scalar differs from impl_scalar_type, but the two types are mutually compatible and have the same size. (They must be bitwise compatible, so that reinterpret_cast makes sense between them.)

Definition at line 361 of file Tpetra_Experimental_BlockView.hpp.

Member Function Documentation

template<class Scalar , class LO >

Scalar* Tpetra::Experimental::LittleVector< Scalar, LO >::getRawPtr ( ) const

inline

Pointer to the block's entries.

Definition at line 375 of file Tpetra_Experimental_BlockView.hpp.

template<class Scalar , class LO >

LO Tpetra::Experimental::LittleVector< Scalar, LO >::getBlockSize ( ) const

inline

The block size (number of degrees of freedom per mesh point).

Definition at line 380 of file Tpetra_Experimental_BlockView.hpp.

template<class Scalar , class LO >

LO Tpetra::Experimental::LittleVector< Scalar, LO >::getStride ( ) const

inline

Stride between consecutive entries.

Definition at line 385 of file Tpetra_Experimental_BlockView.hpp.

template<class Scalar , class LO >

impl_scalar_type& Tpetra::Experimental::LittleVector< Scalar, LO >::operator() ( const LO i ) const

inline

Reference to entry (i) of the vector.

Note: To Tpetra developers: This is returned as impl_scalar_type and not as Scalar, in order to avoid a lot of reinterpret_cast calls in the inner loop of the sparse matrix-vector multiply kernel of Tpetra::Experimental::BlockCrsMatrix. Any pair of types impl_scalar_type, Scalar used here should always be convertible in either direction, so the return type should not pose any issues in practice.

Definition at line 399 of file Tpetra_Experimental_BlockView.hpp.

template<class Scalar , class LO >

template<class LittleVectorType >

void Tpetra::Experimental::LittleVector< Scalar, LO >::update	(	const Scalar &	alpha,
		const LittleVectorType &	X
	)		const

inline

*this := *this + alpha * X.

Definition at line 405 of file Tpetra_Experimental_BlockView.hpp.

template<class Scalar , class LO >

template<class LittleVectorType >

void Tpetra::Experimental::LittleVector< Scalar, LO >::assign ( const LittleVectorType & X ) const

inline

*this := X.

Definition at line 414 of file Tpetra_Experimental_BlockView.hpp.

template<class Scalar , class LO >

void Tpetra::Experimental::LittleVector< Scalar, LO >::scale ( const Scalar & alpha ) const

inline

(*this)(i,j) := alpha * (*this)(i,j) for all (i,j).

Definition at line 421 of file Tpetra_Experimental_BlockView.hpp.

template<class Scalar , class LO >

void Tpetra::Experimental::LittleVector< Scalar, LO >::fill ( const Scalar & alpha ) const

inline

(*this)(i,j) := alpha for all (i,j).

Definition at line 429 of file Tpetra_Experimental_BlockView.hpp.

template<class Scalar , class LO >

template<class LittleVectorType >

void Tpetra::Experimental::LittleVector< Scalar, LO >::absmax ( const LittleVectorType & X ) const

inline

(*this)(i,j) := max(abs((*this)(i,j)), abs(X(i,j))) for all (i,j).

Tpetra uses this operation to implement the ABSMAX CombineMode.

Definition at line 441 of file Tpetra_Experimental_BlockView.hpp.

template<class Scalar , class LO >

template<class LittleVectorType >

bool Tpetra::Experimental::LittleVector< Scalar, LO >::equal ( const LittleVectorType & X ) const

inline

true if and only if all entries of this equal all entries of X.

Definition at line 450 of file Tpetra_Experimental_BlockView.hpp.

template<class Scalar , class LO >

template<class LittleBlockType , class LittleVectorType >

void Tpetra::Experimental::LittleVector< Scalar, LO >::matvecUpdate	(	const Scalar &	alpha,
		const LittleBlockType &	A,
		const LittleVectorType &	X
	)		const

inline

(*this) := (*this) + alpha * A * X (matrix-vector multiply).

Definition at line 465 of file Tpetra_Experimental_BlockView.hpp.

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

Tpetra_Experimental_BlockView.hpp

Public Member Functions

Detailed Description

template<class Scalar, class LO> class Tpetra::Experimental::LittleVector< Scalar, LO >

Constructor & Destructor Documentation

Member Function Documentation

template<class Scalar, class LO>
class Tpetra::Experimental::LittleVector< Scalar, LO >