A load-balancer redistributes grids using the specified partitioner and process-hierarchy. More...

#include <load_balancer.h>

Inheritance diagram for ug::LoadBalancer:

Public Member Functions
void	create_quality_record (const char *label)

virtual void	enable_vertical_interface_creation (bool enable)

	LoadBalancer ()

void	print_last_quality_record () const

void	print_quality_records () const

bool	problems_occurred ()
	indicates whether problems occurred during the last rebalancing. More...

virtual bool	rebalance ()
	performs load balancing if the balance is too bad or if a distribution level has been reached. More...

virtual void	set_balance_threshold (number threshold)
	If the balance falls below the given threshold, then rebalance will perform redistribution. More...

virtual void	set_balance_weights (SPBalanceWeights balanceWeights)
	Sets a callback class which provides the balance weight for a given element. More...

virtual void	set_element_threshold (size_t threshold)

virtual void	set_grid (MultiGrid *mg)

virtual void	set_next_process_hierarchy (SPProcessHierarchy procHierarchy)
	Sets a callback class which provides connection weights between two neighbor elements. More...

virtual void	set_partitioner (SPPartitioner partitioner)
	Sets the partitioner which is used to partition the grid into balanced parts. More...

virtual	~LoadBalancer ()


virtual number	estimate_distribution_quality (std::vector< number > *pLvlQualitiesOut)

number	estimate_distribution_quality ()


virtual void	add_serializer (SPVertexDataSerializer cb)
	add serialization callbacks. More...

virtual void	add_serializer (SPEdgeDataSerializer cb)
	add serialization callbacks. More...

virtual void	add_serializer (SPFaceDataSerializer cb)
	add serialization callbacks. More...

virtual void	add_serializer (SPVolumeDataSerializer cb)
	add serialization callbacks. More...

virtual void	add_serializer (SPGridDataSerializer cb)
	add serialization callbacks. More...

Private Member Functions
template<class TElem >
number	estimate_distribution_quality_impl (std::vector< number > *pLvlQualitiesOut)

Private Attributes
number	m_balanceThreshold

SPBalanceWeights	m_balanceWeights

bool	m_createVerticalInterfaces

size_t	m_elementThreshold

MultiGrid *	m_mg

SPPartitioner	m_partitioner

SPProcessHierarchy	m_processHierarchy

StringStreamTable	m_qualityRecords

GridDataSerializationHandler	m_serializer

Detailed Description

A load-balancer redistributes grids using the specified partitioner and process-hierarchy.

Constructor & Destructor Documentation

◆ LoadBalancer()

ug::LoadBalancer::LoadBalancer ( )

References ug::ProcessHierarchy::create(), m_balanceWeights, m_processHierarchy, and make_sp().

◆ ~LoadBalancer()

ug::LoadBalancer::~LoadBalancer ( )

virtual

Member Function Documentation

◆ add_serializer() [1/5]

virtual void ug::LoadBalancer::add_serializer ( SPEdgeDataSerializer cb )

inlinevirtual

add serialization callbacks.

Used when the grid is being distributed to pack data associated with grid objects or associated classes like subset-handlers.

References ug::GridDataSerializationHandler::add(), and m_serializer.

◆ add_serializer() [2/5]

virtual void ug::LoadBalancer::add_serializer ( SPFaceDataSerializer cb )

inlinevirtual

add serialization callbacks.

Used when the grid is being distributed to pack data associated with grid objects or associated classes like subset-handlers.

References ug::GridDataSerializationHandler::add(), and m_serializer.

◆ add_serializer() [3/5]

virtual void ug::LoadBalancer::add_serializer ( SPGridDataSerializer cb )

inlinevirtual

add serialization callbacks.

Used when the grid is being distributed to pack data associated with grid objects or associated classes like subset-handlers.

References ug::GridDataSerializationHandler::add(), and m_serializer.

◆ add_serializer() [4/5]

virtual void ug::LoadBalancer::add_serializer ( SPVertexDataSerializer cb )

inlinevirtual

add serialization callbacks.

Used when the grid is being distributed to pack data associated with grid objects or associated classes like subset-handlers.

References ug::GridDataSerializationHandler::add(), and m_serializer.

Referenced by ug::DomainLoadBalancer< TDomain >::DomainLoadBalancer().

◆ add_serializer() [5/5]

virtual void ug::LoadBalancer::add_serializer ( SPVolumeDataSerializer cb )

inlinevirtual

add serialization callbacks.

Used when the grid is being distributed to pack data associated with grid objects or associated classes like subset-handlers.

References ug::GridDataSerializationHandler::add(), and m_serializer.

◆ create_quality_record()

void ug::LoadBalancer::create_quality_record ( const char * label )

References estimate_distribution_quality(), m_processHierarchy, m_qualityRecords, ug::Table< T >::num_rows(), and ConstSmartPtr< T, FreePolicy >::valid().

◆ enable_vertical_interface_creation()

void ug::LoadBalancer::enable_vertical_interface_creation ( bool enable )

virtual

References m_createVerticalInterfaces.

◆ estimate_distribution_quality() [1/2]

number ug::LoadBalancer::estimate_distribution_quality ( )

The returned distribution quality represents the global quality of the elements of highest dimension and is the same on all processes. You may optionally specify a pointer to a std::vector which will be filled with the distribution-qualities for each level. By default the pointer is set to NULL and no level-qualities are thus returned. If a process doesn't participate on a given level, it will write -1 to the corresponding entry in pLvlQualitiesOut.

Referenced by create_quality_record(), and rebalance().

◆ estimate_distribution_quality() [2/2]

number ug::LoadBalancer::estimate_distribution_quality ( std::vector< number > * pLvlQualitiesOut )

virtual

The returned distribution quality represents the global quality of the elements of highest dimension and is the same on all processes. You may optionally specify a pointer to a std::vector which will be filled with the distribution-qualities for each level. By default the pointer is set to NULL and no level-qualities are thus returned. If a process doesn't participate on a given level, it will write -1 to the corresponding entry in pLvlQualitiesOut.

References pcl::ProcessCommunicator::allreduce(), ug::EDGE, ug::FACE, m_mg, ug::MultiGrid::num(), PCL_RO_MAX, ug::VERTEX, and ug::VOLUME.

◆ estimate_distribution_quality_impl()

template<class TElem >

number ug::LoadBalancer::estimate_distribution_quality_impl ( std::vector< number > * pLvlQualitiesOut )

private

◆ print_last_quality_record()

void ug::LoadBalancer::print_last_quality_record ( ) const

References m_qualityRecords, ug::Table< T >::num_cols(), ug::Table< T >::num_rows(), and UG_LOG.

◆ print_quality_records()

void ug::LoadBalancer::print_quality_records ( ) const

References m_qualityRecords, and UG_LOG.

◆ problems_occurred()

bool ug::LoadBalancer::problems_occurred ( )

indicates whether problems occurred during the last rebalancing.

This can e.g. happen if the partitioner has problems to create a partition-map which fullfills the given specifications.

Note: if rebalance returns true, still performed rebalancing, even if problems occurred. However, the new partition may not fullfill all given specifications.

References m_partitioner, and SmartPtr< T, FreePolicy >::valid().

◆ rebalance()

bool ug::LoadBalancer::rebalance ( )

virtual

performs load balancing if the balance is too bad or if a distribution level has been reached.

The balance is calculated using the provieded BalanceWeights class. If an imbalance is detected (minBalanceWeight / maxBalanceWeight < balanceThreshold) on a given set of processes, then redistribution will be performed.

If a distribution level has been reached, e.g. due to refinement, the grid will be redistributed on that level even if the balance is perfectly fine.

Note that no redistribution is performed on a given level, if the number of elements on the target process would in average be below the element threshold.

During redistribution the LoadBalancer tries to distribute elements such that the sum of balance weights of elements on each process is the same on a given level. Furthermore it tries to minimize the connection-weights of edges which connect elements on different processes.

The method returns false if e.g. problems during partitioning occurred.

References ug::DistributeGrid(), estimate_distribution_quality(), GDIST_PROFILE_FUNC, ug::LIB_GRID, m_balanceThreshold, m_balanceWeights, m_createVerticalInterfaces, m_elementThreshold, m_mg, m_partitioner, m_processHierarchy, m_serializer, PCL_DEBUG_BARRIER_ALL, UG_COND_THROW, UG_DLOG, UG_LOG, UG_THROW, and SmartPtr< T, FreePolicy >::valid().

◆ set_balance_threshold()

void ug::LoadBalancer::set_balance_threshold ( number threshold )

virtual

If the balance falls below the given threshold, then rebalance will perform redistribution.

Set to 0.9 by default.

References m_balanceThreshold.

◆ set_balance_weights()

void ug::LoadBalancer::set_balance_weights ( SPBalanceWeights balanceWeights )

virtual

Sets a callback class which provides the balance weight for a given element.

Balance weights are used to calculate the current balance and to specify the weight of an element during redistribution.

Note: balance weights are only used if the given partitioner supports them.

References m_balanceWeights.

◆ set_element_threshold()

void ug::LoadBalancer::set_element_threshold ( size_t threshold )

virtual

If distribution on a given level would lead to less elements per process than the given threshold (in average), then no redistribution will be performed on that level. Default is 1.

References m_elementThreshold.

◆ set_grid()

void ug::LoadBalancer::set_grid ( MultiGrid * mg )

virtual

References m_mg.

Referenced by ug::DomainLoadBalancer< TDomain >::DomainLoadBalancer().

◆ set_next_process_hierarchy()

void ug::LoadBalancer::set_next_process_hierarchy ( SPProcessHierarchy procHierarchy )

virtual

Sets a callback class which provides connection weights between two neighbor elements.

The higher the weight, the higher the likelyhood that the two elements will reside on the same process after redistribution.

Note: connection weights are only used if the given partitioner supports them. Defines the process hierarchy which will be used during the following calls of rebalance

References m_processHierarchy.

◆ set_partitioner()

void ug::LoadBalancer::set_partitioner ( SPPartitioner partitioner )

virtual

Sets the partitioner which is used to partition the grid into balanced parts.

References m_partitioner, and partitioner.

Member Data Documentation

◆ m_balanceThreshold

number ug::LoadBalancer::m_balanceThreshold

private

Referenced by rebalance(), and set_balance_threshold().

◆ m_balanceWeights

SPBalanceWeights ug::LoadBalancer::m_balanceWeights

private

Referenced by estimate_distribution_quality_impl(), LoadBalancer(), rebalance(), and set_balance_weights().

◆ m_createVerticalInterfaces

bool ug::LoadBalancer::m_createVerticalInterfaces

private

Referenced by enable_vertical_interface_creation(), and rebalance().

◆ m_elementThreshold

size_t ug::LoadBalancer::m_elementThreshold

private

Referenced by rebalance(), and set_element_threshold().

◆ m_mg

MultiGrid* ug::LoadBalancer::m_mg

private

Referenced by estimate_distribution_quality(), estimate_distribution_quality_impl(), rebalance(), and set_grid().

◆ m_partitioner

SPPartitioner ug::LoadBalancer::m_partitioner

private

Referenced by problems_occurred(), rebalance(), and set_partitioner().

◆ m_processHierarchy

SPProcessHierarchy ug::LoadBalancer::m_processHierarchy

private

Referenced by create_quality_record(), estimate_distribution_quality_impl(), LoadBalancer(), rebalance(), and set_next_process_hierarchy().

◆ m_qualityRecords

StringStreamTable ug::LoadBalancer::m_qualityRecords

private

Referenced by create_quality_record(), print_last_quality_record(), and print_quality_records().

◆ m_serializer

GridDataSerializationHandler ug::LoadBalancer::m_serializer

private

Referenced by add_serializer(), and rebalance().

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

ugbase/lib_grid/parallelization/load_balancer.h
ugbase/lib_grid/parallelization/load_balancer.cpp

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ LoadBalancer()

◆ ~LoadBalancer()

Member Function Documentation

◆ add_serializer() [1/5]

◆ add_serializer() [2/5]

◆ add_serializer() [3/5]

◆ add_serializer() [4/5]

◆ add_serializer() [5/5]

◆ create_quality_record()

◆ enable_vertical_interface_creation()

◆ estimate_distribution_quality() [1/2]

◆ estimate_distribution_quality() [2/2]

◆ estimate_distribution_quality_impl()

◆ print_last_quality_record()

◆ print_quality_records()

◆ problems_occurred()

◆ rebalance()

◆ set_balance_threshold()

◆ set_balance_weights()

◆ set_element_threshold()

◆ set_grid()

◆ set_next_process_hierarchy()

◆ set_partitioner()

Member Data Documentation

◆ m_balanceThreshold

◆ m_balanceWeights

◆ m_createVerticalInterfaces

◆ m_elementThreshold

◆ m_mg

◆ m_partitioner

◆ m_processHierarchy

◆ m_qualityRecords

◆ m_serializer