Detailed Description

template<typename T = unsigned char, typename G = OptimalGrowth>
class walberla::mpi::GenericSendBuffer< T, G >

Implementation of a MPI send buffer.

The SendBuffer class is a special purpose implementation for the MPI communication functionality. It offers a convenient and safe setup of MPI messages even for mixed-type communication. The following example gives an impression of the usage of the SendBuffer class:

using namespace mpi;
 
// Adding a double and an integer to a send buffer
SendBuffer buffer;
double d( 2.1 );
Vec3 v( 3.5, -2.1, 0.7 );
buffer << d << v;
 
// Sending a MPI message to process 0 with the contents of the send buffer
MPI_Send( buffer.ptr(), buffer.size(), MPI_BYTE, 0, 0, MPI_COMM_WORLD );

For another example see also the Buffer Unit Test in File BufferTest.cpp

Note that the order of data values in the send buffer is depending on the order the elements are added to the buffer. This order is not changed during the MPI communication and the same order has to be used during the extraction of the sent data elements. See also the RecvBuffer class description for the receiver side of the MPI communication.

#include <SendBuffer.h>

Classes
class	Ptr

Public Types
using	ElementType = T
	Type of the receive buffer elements. More...

Public Member Functions
Constructors
	GenericSendBuffer (size_t initCapacity=0)
	Standard constructor for SendBuffer. More...

	GenericSendBuffer (const GenericSendBuffer &sb)
	Copy constructor for SendBuffer. More...

Destructor
	~GenericSendBuffer ()
	Destructor for SendBuffer. More...

Assignment operator
GenericSendBuffer &	operator= (const GenericSendBuffer &sb)
	Copy assignment operator for SendBuffer. More...

Get functions
size_t	maxSize () const
	Returns the maximum possible size of the send buffer. More...

size_t	size () const
	Returns the current size of the send buffer. More...

size_t	capacity () const
	Returns the capacity of the send buffer. More...

bool	isEmpty () const
	Returns true if the send buffer is empty. More...

Operators
template<typename V >
std::enable_if< std::is_arithmetic< V >::value\|\|std::is_enum< V >::value, GenericSendBuffer & >::type	operator<< (V value)
	Adds a built-in data value to the send buffer. More...

Repositioning
T *	forward (uint_t elements)
	Forward the given number of elements. More...

void	rewind (const size_t &size)
	Rewinds the stream to a previous position. More...

Utility functions
template<typename VT >
Ptr< VT >	allocate (const size_t length=1, const VT &v=VT())
	Returns a special pointer class to modify the allocated memory location later. More...

T *	ptr () const
	Returns a pointer to the first element of the send buffer. More...

void	reserve (size_t newCapacity)
	Setting the minimum capacity of the send buffer. More...

void	clear ()
	Clearing the send buffer. More...

void	reset ()
	Clearing the send buffer. More...

void	addDebugMarker (const char *marker)
	Adds a debug marker if buffer debugging is enabled. More...

void	extendMemory (size_t newCapacity)
	Extending the internal memory of the send buffer. More...

template<typename V >
std::enable_if< std::is_arithmetic< V >::value\|\|std::is_enum< V >::value, GenericSendBuffer & >::type	put (V value)
	Implements operator<< without debugging system. More...

std::ptrdiff_t	getOffset () const
	Returns the offset from the beginning to the current position inside the buffer in bytes. More...

T *	getMemoryLocation (const std::ptrdiff_t offset)
	Returns the memory address corresponding to the offset. More...

Member variables
T *	begin_
	Pointer to the first element of the send buffer. More...

T *	cur_
	Pointer to the current/last element of the send buffer. More...

T *	end_
	Pointer to the end of the storage of the send buffer. More...

template<typename U >
class	GenericRecvBuffer

Member Typedef Documentation

◆ ElementType

template<typename T = unsigned char, typename G = OptimalGrowth>

using walberla::mpi::GenericSendBuffer< T, G >::ElementType = T

Type of the receive buffer elements.

Constructor & Destructor Documentation

◆ GenericSendBuffer() [1/2]

template<typename T , typename G >

walberla::mpi::GenericSendBuffer< T, G >::GenericSendBuffer ( size_t initCapacity = 0 )

inlineexplicit

Standard constructor for SendBuffer.

Parameters

initCapacity The initial capacity of the send buffer.

The default initial capacity of the send buffer is specified by the selected growth policy.

◆ GenericSendBuffer() [2/2]

template<typename T , typename G >

walberla::mpi::GenericSendBuffer< T, G >::GenericSendBuffer ( const GenericSendBuffer< T, G > & sb )

inline

Copy constructor for SendBuffer.

Parameters

sb	The send buffer to be copied.

◆ ~GenericSendBuffer()

template<typename T , typename G >

walberla::mpi::GenericSendBuffer< T, G >::~GenericSendBuffer

inline

Destructor for SendBuffer.

Member Function Documentation

◆ addDebugMarker()

template<typename T , typename G >

void walberla::mpi::GenericSendBuffer< T, G >::addDebugMarker ( const char * marker )

inline

Adds a debug marker if buffer debugging is enabled.

See corresponding function GenericRecvBuffer::readDebugMarker()

◆ allocate()

template<typename T = unsigned char, typename G = OptimalGrowth>

template<typename VT >

Ptr<VT> walberla::mpi::GenericSendBuffer< T, G >::allocate	(	const size_t	length = `1`,
		const VT &	v = `VT()`
	)

inline

Returns a special pointer class to modify the allocated memory location later.

Example:

   int a = 1;
   int b = 2;
   int c = 3;
   SendBuffer sb;
   auto ptr = sb.allocate<int>(2);
   sb << b << c;
   *ptr   = a;
   ptr[1] = c;
   //ptr[2] = c; // will fail in debug: out of bounds

The buffer now contains 1, 3, 2, 3

◆ capacity()

template<typename T , typename G >

size_t walberla::mpi::GenericSendBuffer< T, G >::capacity

inline

Returns the capacity of the send buffer.

Returns: The capacity.

◆ clear()

template<typename T , typename G >

void walberla::mpi::GenericSendBuffer< T, G >::clear

inline

Clearing the send buffer.

Returns: void

This function performs a complete reset of the send buffer.

◆ extendMemory()

template<typename T , typename G >

void walberla::mpi::GenericSendBuffer< T, G >::extendMemory ( size_t newCapacity )

private

Extending the internal memory of the send buffer.

Parameters

newCapacity The new minimum capacity of the send buffer.

Returns: void

◆ forward()

template<typename T , typename G >

T * walberla::mpi::GenericSendBuffer< T, G >::forward ( uint_t elements )

inline

Forward the given number of elements.

Parameters

elements The number of elements to be advanced.

Returns: Previous position.

This function forwards element send buffer elements of type T and returns the previous buffer position.

◆ getMemoryLocation()

template<typename T , typename G >

T * walberla::mpi::GenericSendBuffer< T, G >::getMemoryLocation ( const std::ptrdiff_t offset )

inlineprivate

Returns the memory address corresponding to the offset.

Offset is measured in bytes from the beginning of the buffer.

Attention: This is a low level function. Use with care!

See also: getOffset()

◆ getOffset()

template<typename T , typename G >

std::ptrdiff_t walberla::mpi::GenericSendBuffer< T, G >::getOffset

inlineprivate

Returns the offset from the beginning to the current position inside the buffer in bytes.

Attention: This is a low level function. Use with care!

See also: getMemoryLocation()

◆ isEmpty()

template<typename T , typename G >

bool walberla::mpi::GenericSendBuffer< T, G >::isEmpty

inline

Returns true if the send buffer is empty.

Returns: true if the send buffer is empty, false if it is not.

◆ maxSize()

template<typename T , typename G >

size_t walberla::mpi::GenericSendBuffer< T, G >::maxSize

inline

Returns the maximum possible size of the send buffer.

Returns: The maximum possible size.

◆ operator<<()

template<typename T , typename G >

template<typename V >

std::enable_if< std::is_arithmetic< V >::value||std::is_enum< V >::value, GenericSendBuffer< T, G > & >::type walberla::mpi::GenericSendBuffer< T, G >::operator<< ( V value )

Adds a built-in data value to the send buffer.

Returns: Reference to the send buffer.

This function adds one data value of built-in data type to the send buffer.

Note: This operator may only be used for built-in data types. The attempt to use a user-defined data type results in a compile time error!

◆ operator=()

template<typename T , typename G >

GenericSendBuffer< T, G > & walberla::mpi::GenericSendBuffer< T, G >::operator= ( const GenericSendBuffer< T, G > & sb )

Copy assignment operator for SendBuffer.

Parameters

sb	The send buffer to be copied.

Returns: Reference to the assigned send buffer.

◆ ptr()

template<typename T , typename G >

T * walberla::mpi::GenericSendBuffer< T, G >::ptr

inline

Returns a pointer to the first element of the send buffer.

Returns: Pointer to the first element of the send buffer.

This utility function enables the SendBuffer to be used directly as send buffer in MPI send functions:

using namespace communication;
 
// Filling a send buffer with a double and an integer value
SendBuffer<byte> buffer;
double d =  2.1;
int i= 2;
buffer << d << i;
 
// Sending a MPI message to process 0 with the contents of the send buffer
MPI_Send( buffer.ptr(), buffer.size(), MPI_BYTE, 0, 0, MPI_COMM_WORLD );

◆ put()

template<typename T , typename G >

template<typename V >

std::enable_if< std::is_arithmetic< V >::value||std::is_enum< V >::value, GenericSendBuffer< T, G > & >::type walberla::mpi::GenericSendBuffer< T, G >::put ( V value )

private

Implements operator<< without debugging system.

Returns: Reference to the send buffer.

◆ reserve()

template<typename T , typename G >

void walberla::mpi::GenericSendBuffer< T, G >::reserve ( size_t newCapacity )

inline

Setting the minimum capacity of the send buffer.

Parameters

newCapacity The new minimum capacity of the send buffer.

Returns: void

This function reserves at least newCapacity elements of data type T for the send buffer.

◆ reset()

template<typename T , typename G >

void walberla::mpi::GenericSendBuffer< T, G >::reset

inline

Clearing the send buffer.

Returns: void

This function performs a complete reset of the send buffer - including the deletion of allocated memory!

◆ rewind()

template<typename T , typename G >

void walberla::mpi::GenericSendBuffer< T, G >::rewind ( const size_t & s )

inline

Rewinds the stream to a previous position.

// Filling a send buffer with a double and an integer value
SendBuffer<byte> buffer;
double d =  2.1;
buffer << d;
size_t memorizedSize = buffer.size();
int i=3;
buffer << i;
buffer.rewind(memorizedSize);
i=5;
buffer << i; //overwrites the 3 in the buffer with the new value 5

◆ size()

template<typename T , typename G >

size_t walberla::mpi::GenericSendBuffer< T, G >::size

inline

Returns the current size of the send buffer.

Returns: The current size.

Friends And Related Function Documentation

◆ GenericRecvBuffer

template<typename T = unsigned char, typename G = OptimalGrowth>

template<typename U >

friend class GenericRecvBuffer

friend

Member Data Documentation

◆ begin_

template<typename T = unsigned char, typename G = OptimalGrowth>

T* walberla::mpi::GenericSendBuffer< T, G >::begin_

private

Pointer to the first element of the send buffer.

◆ cur_

template<typename T = unsigned char, typename G = OptimalGrowth>

T* walberla::mpi::GenericSendBuffer< T, G >::cur_

private

Pointer to the current/last element of the send buffer.

◆ end_

template<typename T = unsigned char, typename G = OptimalGrowth>

T* walberla::mpi::GenericSendBuffer< T, G >::end_

private

Pointer to the end of the storage of the send buffer.

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

/builds/administration/walberla-website/walberla/src/core/mpi/SendBuffer.h

Detailed Description

template<typename T = unsigned char, typename G = OptimalGrowth> class walberla::mpi::GenericSendBuffer< T, G >

Classes

Public Types

Public Member Functions

Utility functions

Member variables

Member Typedef Documentation

◆ ElementType

Constructor & Destructor Documentation

◆ GenericSendBuffer() [1/2]

◆ GenericSendBuffer() [2/2]

◆ ~GenericSendBuffer()

Member Function Documentation

◆ addDebugMarker()

◆ allocate()

◆ capacity()

◆ clear()

◆ extendMemory()

◆ forward()

◆ getMemoryLocation()

◆ getOffset()

◆ isEmpty()

◆ maxSize()

◆ operator<<()

◆ operator=()

◆ ptr()

◆ put()

◆ reserve()

◆ reset()

◆ rewind()

◆ size()

Friends And Related Function Documentation

◆ GenericRecvBuffer

Member Data Documentation

◆ begin_

◆ cur_

◆ end_

template<typename T = unsigned char, typename G = OptimalGrowth>
class walberla::mpi::GenericSendBuffer< T, G >