The Template WriteAccess is used to enforce the consistency of the template LAMAArray. More...

#include <WriteAccess.hpp>

Inheritance diagram for lama::WriteAccess< T >:

Public Types
typedef T	ValueType
	ValueType is the type stored in the wrapped container.
Public Member Functions
	WriteAccess (LAMAArray< ValueType > &array, ContextPtr context)
	acquire a WriteAccess to the passed LAMAArray for the passed location
	WriteAccess (LAMAArray< ValueType > &array, ContextPtr context, const IndexType size, const bool keep)
	acquire a WriteAccess to the passed LAMAArray for the passed location with resize
	WriteAccess (LAMAArray< ValueType > &array)
	acquire a WriteAccess to the passed LAMAArray for a valid context.
	WriteAccess (LAMAArrayView< ValueType > &view, ContextPtr context, const bool keep=true)
	WriteAccess (LAMAArrayView< ValueType > &view, ContextPtr context, const IndexType size, const bool keep=true)
virtual	~WriteAccess ()
	Releases the WriteAccess on the associated LAMAArray.
ValueType *	get ()
	returns a pointer to the data of the wrapped LAMAArray
void	clear ()
	Set the size of the LAMAArray to 0.
void	resize (const IndexType newSize)
	resizes the wrapped LAMAArray
void	reserve (const IndexType capacity)
	reserve storage for wth wrapped LAMAArray at the associated location
IndexType	capacity () const
	query the capacity of the array on the reserved context
virtual void	release ()
	Releases the WriteAccess on the associated LAMAArray.
virtual void	writeAt (std::ostream &stream) const
	Writes some Information about this to the passed stream.
IndexType	size () const
	Returns the size of the wrapped LAMAArray.
Protected Member Functions
	LAMA_LOG_DECL_STATIC_LOGGER (logger)
Protected Attributes
ValueType *	mData
LAMAArrayView< ValueType > *	mArrayView
size_t	mIndex

Detailed Description

template<typename T>
class lama::WriteAccess< T >

The Template WriteAccess is used to enforce the consistency of the template LAMAArray.

WriteAccess enforces the consistency of the template LAMAArray by following the RAII Idiom. This is done by acquiring a write lock on a LAMAArray in the constructor and releasing this write lock in the destructor. There for a WriteAccess should be only used as a stack object.

Member Typedef Documentation

template<typename T>

typedef T lama::WriteAccess< T >::ValueType

ValueType is the type stored in the wrapped container.

Reimplemented in lama::WriteOnlyAccess< T >, lama::HostWriteOnlyAccess< T >, and lama::HostWriteAccess< T >.

Constructor & Destructor Documentation

template<typename T >

lama::WriteAccess< T >::WriteAccess	(	LAMAArray< ValueType > &	array,
		ContextPtr	context
	)

acquire a WriteAccess to the passed LAMAArray for the passed location

Parameters:

[in]	array	the LAMAArray to acquire a WriteAccess for
[in]	context	the context to acquire a WriteAccess for

Exceptions:

Exception if the WriteAccess can not be acquired, e.g. because another WriteAccess exists.

This constructor acquires a WriteAccess to the passed LAMAArray for the passed location. Depending on the flag keep the LAMAArray is updated on location or not. This flag can be used to acquire write only access, e.g. if one want to write only to the passed wrapped LAMAArray. If the passed LAMAArray is not valid at location and keep is true the LAMAArray will be made valid at location before this constructor returns.

References lama::LAMAArrayView< T >::acquireWriteAccess(), lama::LAMAArrayView< T >::get(), lama::WriteAccess< T >::mArrayView, lama::WriteAccess< T >::mData, and lama::WriteAccess< T >::mIndex.

template<typename T >

lama::WriteAccess< T >::WriteAccess	(	LAMAArray< ValueType > &	array,
		ContextPtr	context,
		const IndexType	size,
		const bool	keep
	)

acquire a WriteAccess to the passed LAMAArray for the passed location with resize

Parameters:

[in]	array	the LAMAArray to acquire a WriteAccess for
[in]	context	the context to acquire a WriteAccess for
[in]	size	the new size of the LAMA array
[in]	keep	if false, implicit clear, old values of the array are no more needed

Exceptions:

Exception if the WriteAccess can not be acquired, e.g. because another WriteAccess exists.

If the keep flag is set to false, no valid data must be transferred between different devices and it is no memory copy needed in case of a reallocation.

    WriteAccess wData( context, data, 100, false );
    // same as
    data.clear(); WriteAccess wData( context, data ); wData.resize( size );
    // better than this solution that might still have transfers            
    WriteAccess wData( context, data ); wData.clear(); wData.resize( size );

Attention: this kind of write access assumes that the array is completely new written.

References lama::LAMAArrayView< T >::acquireWriteAccess(), lama::LAMAArrayView< T >::clear(), lama::LAMAArrayView< T >::get(), lama::WriteAccess< T >::mArrayView, lama::WriteAccess< T >::mData, lama::WriteAccess< T >::mIndex, and lama::LAMAArrayView< T >::resize().

template<typename T >

lama::WriteAccess< T >::WriteAccess ( LAMAArray< ValueType > & array ) [explicit]

acquire a WriteAccess to the passed LAMAArray for a valid context.

Parameters:

[in] array the LAMAArray to acquire a WriteAccess for

Exceptions:

Exception if the WriteAccess can not be acquired, e.g. because another WriteAccess exists.

This constructor acquires a WriteAccess to the passed LAMAArray for a valid location. The chosen Location will be the first valid location. This Access can be used to call, e.g. resize. If it does not matter where the data currently resides.

References lama::LAMAArrayView< T >::acquireWriteAccess(), lama::LAMAArrayView< T >::get(), lama::WriteAccess< T >::mArrayView, lama::WriteAccess< T >::mData, and lama::WriteAccess< T >::mIndex.

template<typename T >

lama::WriteAccess< T >::WriteAccess	(	LAMAArrayView< ValueType > &	view,
		ContextPtr	context,
		const bool	keep = `true`
	)

References lama::LAMAArrayView< T >::acquireWriteAccess(), lama::LAMAArrayView< T >::get(), lama::WriteAccess< T >::mArrayView, lama::WriteAccess< T >::mData, and lama::WriteAccess< T >::mIndex.

template<typename T >

lama::WriteAccess< T >::WriteAccess	(	LAMAArrayView< ValueType > &	view,
		ContextPtr	context,
		const IndexType	size,
		const bool	keep = `true`
	)

References lama::LAMAArrayView< T >::acquireWriteAccess(), lama::LAMAArrayView< T >::clear(), lama::LAMAArrayView< T >::get(), lama::WriteAccess< T >::mArrayView, lama::WriteAccess< T >::mData, lama::WriteAccess< T >::mIndex, and lama::LAMAArrayView< T >::resize().

template<typename T >

lama::WriteAccess< T >::~WriteAccess ( ) [virtual]

Releases the WriteAccess on the associated LAMAArray.

Member Function Documentation

template<typename T >

IndexType lama::WriteAccess< T >::capacity ( ) const

query the capacity of the array on the reserved context

References LAMA_ASSERT_ERROR.

Referenced by lama::Communicator::shift().

template<typename T >

void lama::WriteAccess< T >::clear ( )

Set the size of the LAMAArray to 0.

This operation only sets the size but does not free any reserved memory.

This operation should always be called when an array is completely rewritten. to avoid that data will be transfered from other locations or copying of old values during the resize.

   LAMAArray& arr = ...
   arr.clear();
   HostWriteAccess writeArr( arr );
   writeArr.resize( 100 );
   for ( int i = 0; i < 100; i++)
   {
       writeArr[i] = 0.0;
   }

References LAMA_ASSERT_ERROR.

Referenced by lama::Communicator::exchangeByPlan(), and lama::_MatrixStorage::offsets2sizes().

template<typename T >

T * lama::WriteAccess< T >::get ( )

returns a pointer to the data of the wrapped LAMAArray