Calculates the distribution of FABs to MPI processes. More...

#include <AMReX_DistributionMapping.H>

Classes
struct	Ref

struct	RefID
	Lightweight identity handle wrapping a pointer to the underlying Ref. More...

Public Types
enum	Strategy { UNDEFINED = -1 , ROUNDROBIN , KNAPSACK , SFC , RRSFC }
	The distribution strategies. More...

Public Member Functions
	DistributionMapping () noexcept
	The default constructor.

	DistributionMapping (const DistributionMapping &rhs)=default
	The copy constructor.

DistributionMapping &	operator= (const DistributionMapping &rhs)=default
	The copy assignment operator.

	DistributionMapping (DistributionMapping &&rhs) noexcept=default
	The move constructor.

DistributionMapping &	operator= (DistributionMapping &&rhs) noexcept=default
	The move assignment operator.

	~DistributionMapping () noexcept=default
	The destructor.

	DistributionMapping (const Vector< int > &pmap)
	Create an object with an explicit processor map.

	DistributionMapping (Vector< int > &&pmap) noexcept
	Create an object with an explicit processor map (rvalue overload).

	DistributionMapping (const BoxArray &boxes, int nprocs=ParallelDescriptor::NProcs())
	Build a mapping from a BoxArray using the current strategy.

	DistributionMapping (std::shared_ptr< Ref > a_ref)
	Construct from an existing shared Ref handle `a_ref` (advanced use).

	DistributionMapping (const DistributionMapping &d1, const DistributionMapping &d2)
	Construct by concatenating the processor maps from two existing mappings.

void	define (const BoxArray &boxes, int nprocs=ParallelDescriptor::NProcs())
	Build a mapping from a BoxArray using the current strategy.

void	define (const Vector< int > &pmap)
	Build mapping out of a Vector of ints.

void	define (Vector< int > &&pmap) noexcept
	Build mapping out of a Vector of ints (rvalue overload).

const Vector< int > &	ProcessorMap () const noexcept
	Returns a constant reference to the mapping of boxes in the underlying BoxArray to the CPU that holds the FAB on that Box.

Long	size () const noexcept
	Length of the underlying processor map.

Long	capacity () const noexcept
	Reserved capacity of the underlying processor map.

bool	empty () const noexcept
	Return `true` if the processor map is empty.

Long	linkCount () const noexcept
	Number of references to this DistributionMapping.

int	operator[] (int index) const noexcept
	Equivalent to ProcessorMap()[index].

std::istream &	readFrom (std::istream &is)
	Read the distribution mapping from formatted text stream `is`.

std::ostream &	writeOn (std::ostream &os) const
	Write the distribution mapping to formatted text stream `os`.

bool	operator== (const DistributionMapping &rhs) const noexcept
	Are the distributions equal?

bool	operator!= (const DistributionMapping &rhs) const noexcept
	Are the distributions different?

void	SFCProcessorMap (const BoxArray &boxes, const std::vector< Long > &wgts, int nprocs, bool sort=true)
	Build an SFC-ordered map for `boxes` with per-box weights `wgts`.

void	SFCProcessorMap (const BoxArray &boxes, const std::vector< Long > &wgts, int nprocs, Real &efficiency, bool sort=true)
	Build an SFC-ordered map and report the resulting efficiency.

void	KnapSackProcessorMap (const std::vector< Long > &wgts, int nprocs, Real *efficiency=nullptr, bool do_full_knapsack=true, int nmax=std::numeric_limits< int >::max(), bool sort=true)
	Build a knapsack map from a weight vector.

void	KnapSackProcessorMap (const DistributionMapping &olddm, const std::vector< Long > &wgts, Real keep_ratio, Real &old_efficiency, Real &new_efficiency, int nmax=std::numeric_limits< int >::max())
	Incrementally re-balance using the knapsack algorithm, retaining boxes on their original ranks up to a fraction `keep_ratio` of the average per-rank weight before redistributing the remainder.

void	RoundRobinProcessorMap (int nboxes, int nprocs, bool sort=true)
	Build a round-robin map for `nboxes` boxes.

void	RoundRobinProcessorMap (const std::vector< Long > &wgts, int nprocs, bool sort=true)
	Build a round-robin map from a weight vector.

std::weak_ptr< Ref >	getWeakRef () const
	Return a weak pointer to the underlying Ref (for low-level identity tracking).

RefID	getRefID () const noexcept
	This gives a unique ID of the reference, which is different from dmID above.

Static Public Member Functions
static void	strategy (Strategy how)
	Set the default DistributionMapping strategy used by the constructors.

static Strategy	strategy ()
	Return the current default DistributionMapping strategy.

static void	SFC_Threshold (int n)
	Set the SFC threshold `n` (clamped to >= 1); SFC ordering is used only when boxes.size() >= n*nprocs.

static int	SFC_Threshold ()
	Return the SFC threshold; the SFC constructors fall back to knapsack when boxes.size() < threshold*nprocs.

static void	Initialize ()
	Initializes distribution strategy from ParmParse.

static void	Finalize ()
	Finalize the DistributionMapping subsystem.

static bool	SameRefs (const DistributionMapping &lhs, const DistributionMapping &rhs)
	Return `true` if `lhs` and `rhs` share the same underlying Ref.

static DistributionMapping	makeKnapSack (const MultiFab &weight, int nmax=std::numeric_limits< int >::max())
	Build a knapsack mapping weighted by the sum of component 0 over each valid box of `weight`.

static DistributionMapping	makeKnapSack (const MultiFab &weight, Real &eff, int nmax=std::numeric_limits< int >::max())
	Build a knapsack mapping weighted by the sum of component 0 over each valid box of `weight` and report efficiency.

static DistributionMapping	makeKnapSack (const Vector< Real > &rcost, int nmax=std::numeric_limits< int >::max())
	Build a knapsack mapping from an explicit cost vector.

static DistributionMapping	makeKnapSack (const Vector< Real > &rcost, Real &eff, int nmax=std::numeric_limits< int >::max(), bool sort=true)
	Build a knapsack mapping from `rcost` and report efficiency.

static DistributionMapping	makeKnapSack (const LayoutData< Real > &rcost_local, Real &currentEfficiency, Real &proposedEfficiency, int nmax=std::numeric_limits< int >::max(), bool broadcastToAll=true, int root=ParallelDescriptor::IOProcessorNumber(), Real keep_ratio=Real(0.0))
	Computes a new distribution mapping by distributing input costs according to the `knapsack` algorithm.

static DistributionMapping	makeRoundRobin (const MultiFab &weight)
	Build a round-robin map weighted by the sum of component 0 over each valid box of `weight`.

static DistributionMapping	makeSFC (const MultiFab &weight, bool sort=true)
	Build an SFC map weighted by the sum of component 0 over each valid box of `weight`; `sort` enables load-aware ordering.

static DistributionMapping	makeSFC (const MultiFab &weight, Real &eff, bool sort=true)
	Build an SFC map weighted by the sum of component 0 over each valid box of `weight`, write efficiency to `eff`, and optionally use load-aware ordering.

static DistributionMapping	makeSFC (const Vector< Real > &rcost, const BoxArray &ba, bool sort=true)
	Build an SFC map from `rcost` and `ba`; `sort` enables load-aware bucket and rank/team ordering.

static DistributionMapping	makeSFC (const Vector< Real > &rcost, const BoxArray &ba, Real &eff, bool sort=true)
	Build an SFC map from `rcost` and `ba`, write efficiency to `eff`, and optionally use load-aware ordering.

static DistributionMapping	makeSFC (const LayoutData< Real > &rcost_local, Real &currentEfficiency, Real &proposedEfficiency, bool broadcastToAll=true, int root=ParallelDescriptor::IOProcessorNumber())
	Computes a new distribution mapping by distributing input costs according to a `space filling curve` (SFC) algorithm.

static std::vector< std::vector< int > >	makeSFC (const BoxArray &ba, bool use_box_vol=true, int nprocs=ParallelContext::NProcsSub())

template<typename T >
static void	ComputeDistributionMappingEfficiency (const DistributionMapping &dm, const std::vector< T > &cost, Real *efficiency)
	Computes the average cost per MPI rank given a distribution mapping global cost vector.

static Vector< Long >	ConvertCostRealToLong (const Vector< Real > &rcost)

Friends
template<typename T >
class	FabArray

class	FabArrayBase

Detailed Description

Calculates the distribution of FABs to MPI processes.

This class calculates the distribution of FABs to MPI processes in a FabArray in a multi-processor environment. By distribution is meant what MPI process in the multi-processor environment owns what FAB. Only the BoxArray on which the FabArray is built is used in determining the distribution. The four distribution strategies are round-robin, knapsack, SFC, and RRSFC. In the round-robin distribution, boxes are ordered from largest to smallest and assigned cyclically to ranks or teams, starting with those using the least FAB memory. In the knapsack distribution the FABs are partitioned across CPUs such that the total volume of the Boxes in the underlying BoxArray are as equal across CPUs as is possible. The SFC distribution is based on a space filling curve. The RRSFC distribution orders boxes using an SFC and then assigns them in round-robin order to CPUs ordered from least to most FAB memory use.

Member Enumeration Documentation

◆ Strategy

enum amrex::DistributionMapping::Strategy

The distribution strategies.

Enumerator
UNDEFINED
ROUNDROBIN
KNAPSACK
SFC
RRSFC

Constructor & Destructor Documentation

◆ DistributionMapping() [1/8]

amrex::DistributionMapping::DistributionMapping ( )

noexcept

The default constructor.

◆ DistributionMapping() [2/8]

amrex::DistributionMapping::DistributionMapping ( const DistributionMapping & rhs )

default

The copy constructor.

◆ DistributionMapping() [3/8]

amrex::DistributionMapping::DistributionMapping ( DistributionMapping && rhs )

defaultnoexcept

The move constructor.

◆ ~DistributionMapping()

amrex::DistributionMapping::~DistributionMapping ( )

defaultnoexcept

The destructor.

◆ DistributionMapping() [4/8]

amrex::DistributionMapping::DistributionMapping ( const Vector< int > & pmap )

explicit

Create an object with an explicit processor map.

Parameters

pmap	Processor id for each box in the underlying BoxArray.

◆ DistributionMapping() [5/8]

amrex::DistributionMapping::DistributionMapping ( Vector< int > && pmap )

explicitnoexcept

Create an object with an explicit processor map (rvalue overload).

Parameters

pmap	Processor id for each box in the underlying BoxArray.

◆ DistributionMapping() [6/8]

amrex::DistributionMapping::DistributionMapping	(	const BoxArray &	boxes,
		int	nprocs = `ParallelDescriptor::NProcs()`
	)

explicit

Build a mapping from a BoxArray using the current strategy.

Parameters

boxes	Boxes to distribute.
nprocs	Number of processes requested for the mapping.

◆ DistributionMapping() [7/8]

amrex::DistributionMapping::DistributionMapping ( std::shared_ptr< Ref > a_ref )

explicit

Construct from an existing shared Ref handle a_ref (advanced use).

◆ DistributionMapping() [8/8]

amrex::DistributionMapping::DistributionMapping	(	const DistributionMapping &	d1,
		const DistributionMapping &	d2
	)

Construct by concatenating the processor maps from two existing mappings.

This is a very specialized constructor. The resulting map is only valid for a FabArray whose BoxArray is the corresponding concatenation of those of d1 and d2.

Parameters

d1	Mapping whose processor ids are inserted first.
d2	Mapping whose processor ids are appended to the result.

Member Function Documentation

◆ capacity()

Long amrex::DistributionMapping::capacity ( ) const

inlinenoexcept

Reserved capacity of the underlying processor map.

◆ ComputeDistributionMappingEfficiency()

template<typename T >

void amrex::DistributionMapping::ComputeDistributionMappingEfficiency	(	const DistributionMapping &	dm,
		const std::vector< T > &	cost,
		Real *	efficiency
	)

static

Computes the average cost per MPI rank given a distribution mapping global cost vector.

Parameters

[in]	dm	distribution mapping (mapping from FAB to MPI processes)
[in]	cost	vector giving mapping from FAB to the corresponding cost
[in,out]	efficiency	average cost per MPI process, as computed from the given distribution mapping and cost

◆ ConvertCostRealToLong()

Vector< Long > amrex::DistributionMapping::ConvertCostRealToLong ( const Vector< Real > & rcost )

static

Convert cost vector from Real to Long. Other than convenience, this also provides a consistent way for the conversion.

◆ define() [1/3]

void amrex::DistributionMapping::define	(	const BoxArray &	boxes,
		int	nprocs = `ParallelDescriptor::NProcs()`
	)

Build a mapping from a BoxArray using the current strategy.

This overload can be used to initialize a default-constructed DistributionMapping.

Parameters

boxes	Boxes to distribute.
nprocs	Number of processes requested for the mapping.

◆ define() [2/3]

void amrex::DistributionMapping::define ( const Vector< int > & pmap )

Build mapping out of a Vector of ints.

This overload can be used to initialize a default-constructed DistributionMapping.

◆ define() [3/3]

void amrex::DistributionMapping::define ( Vector< int > && pmap )

noexcept

Build mapping out of a Vector of ints (rvalue overload).

This overload can be used to initialize a default-constructed DistributionMapping.

◆ empty()

bool amrex::DistributionMapping::empty ( ) const

inlinenoexcept

Return true if the processor map is empty.

◆ Finalize()

void amrex::DistributionMapping::Finalize ( )

static

Finalize the DistributionMapping subsystem.

◆ getRefID()

RefID amrex::DistributionMapping::getRefID ( ) const

inlinenoexcept

This gives a unique ID of the reference, which is different from dmID above.

◆ getWeakRef()

std::weak_ptr< DMRef > amrex::DistributionMapping::getWeakRef ( ) const

Return a weak pointer to the underlying Ref (for low-level identity tracking).

◆ Initialize()

void amrex::DistributionMapping::Initialize ( )

static

Initializes distribution strategy from ParmParse.

ParmParse options are:

DistributionMapping.strategy = ROUNDROBIN DistributionMapping.strategy = KNAPSACK DistributionMapping.strategy = SFC # the default DistributionMapping.strategy = RRSFC

◆ KnapSackProcessorMap() [1/2]

void amrex::DistributionMapping::KnapSackProcessorMap	(	const DistributionMapping &	olddm,
		const std::vector< Long > &	wgts,
		Real	keep_ratio,
		Real &	old_efficiency,
		Real &	new_efficiency,
		int	nmax = `std::numeric_limits<int>::max()`
	)

Incrementally re-balance using the knapsack algorithm, retaining boxes on their original ranks up to a fraction keep_ratio of the average per-rank weight before redistributing the remainder.

Parameters

olddm	Original mapping.
wgts	Per-box weights.
keep_ratio	Fraction of the average per-rank weight to retain on each original rank.
old_efficiency	Output efficiency of the old mapping.
new_efficiency	Output efficiency of the new mapping.
nmax	Maximum boxes per rank.

◆ KnapSackProcessorMap() [2/2]

void amrex::DistributionMapping::KnapSackProcessorMap	(	const std::vector< Long > &	wgts,
		int	nprocs,
		Real *	efficiency = `nullptr`,
		bool	do_full_knapsack = `true`,
		int	nmax = `std::numeric_limits<int>::max()`,
		bool	sort = `true`
	)

Build a knapsack map from a weight vector.

Parameters

wgts	Per-box weights (e.g., cell counts).
nprocs	Number of processes requested for the mapping.
efficiency	Optional load-balance efficiency output (nullptr to skip).
do_full_knapsack	When false, use the cheaper approximate solver.
nmax	Maximum boxes owned by a single rank.
sort	When true, sort the knapsack buckets by weight and map them onto the least-used ranks or teams.

◆ linkCount()

Long amrex::DistributionMapping::linkCount ( ) const

inlinenoexcept

Number of references to this DistributionMapping.

◆ makeKnapSack() [1/5]

DistributionMapping amrex::DistributionMapping::makeKnapSack	(	const LayoutData< Real > &	rcost_local,
		Real &	currentEfficiency,
		Real &	proposedEfficiency,
		int	nmax = `std::numeric_limits<int>::max()`,
		bool	broadcastToAll = `true`,
		int	root = `ParallelDescriptor::IOProcessorNumber()`,
		Real	keep_ratio = `Real(0.0)`
	)

static

Computes a new distribution mapping by distributing input costs according to the knapsack algorithm.

Parameters

[in]	rcost_local	LayoutData of costs; contains, e.g., costs for the local boxes in the FAB array, corresponding indices in the global indices in the FAB array, and the distribution mapping
[in,out]	currentEfficiency	On the root process, this is the efficiency (i.e., mean cost over all MPI ranks, normalized to the max cost) given the current distribution mapping
[in,out]	proposedEfficiency	On the root process, this is the efficiency for the proposed distribution mapping
[in]	nmax	the maximum number of boxes that can be assigned to any MPI rank by the knapsack algorithm
[in]	broadcastToAll	controls whether to transmit the proposed distribution mapping to all other processes; setting this to false allows to, e.g., test whether the proposed distribution mapping is an improvement relative to the current distribution mapping, before deciding to broadcast the proposed distribution mapping
[in]	root	which process to collect the local costs from others and compute the proposed distribution mapping
[in]	keep_ratio	controls the fraction of load that should be kept on the original process.

Returns: the proposed load-balanced distribution mapping

◆ makeKnapSack() [2/5]

DistributionMapping amrex::DistributionMapping::makeKnapSack	(	const MultiFab &	weight,
		int	nmax = `std::numeric_limits<int>::max()`
	)

static

Build a knapsack mapping weighted by the sum of component 0 over each valid box of weight.

Parameters

weight	MultiFab supplying per-box costs through the sum of component 0 over each valid box.
nmax	Maximum boxes per rank.

◆ makeKnapSack() [3/5]

DistributionMapping amrex::DistributionMapping::makeKnapSack	(	const MultiFab &	weight,
		Real &	eff,
		int	nmax = `std::numeric_limits<int>::max()`
	)

static

Build a knapsack mapping weighted by the sum of component 0 over each valid box of weight and report efficiency.

Parameters

weight	MultiFab supplying per-box costs through the sum of component 0 over each valid box.
eff	Output load-balance efficiency.
nmax	Maximum boxes per rank.

◆ makeKnapSack() [4/5]

DistributionMapping amrex::DistributionMapping::makeKnapSack	(	const Vector< Real > &	rcost,
		int	nmax = `std::numeric_limits<int>::max()`
	)

static

Build a knapsack mapping from an explicit cost vector.

Parameters

rcost	Per-box costs.
nmax	Maximum boxes per rank.

◆ makeKnapSack() [5/5]

DistributionMapping amrex::DistributionMapping::makeKnapSack	(	const Vector< Real > &	rcost,
		Real &	eff,
		int	nmax = `std::numeric_limits<int>::max()`,
		bool	sort = `true`
	)

static

Build a knapsack mapping from rcost and report efficiency.

Parameters

rcost	Per-box costs.
eff	Output load-balance efficiency.
nmax	Maximum boxes per rank.
sort	When true, sort the knapsack buckets by weight and map them onto the least-used ranks or teams.

◆ makeRoundRobin()

DistributionMapping amrex::DistributionMapping::makeRoundRobin ( const MultiFab & weight )

static

Build a round-robin map weighted by the sum of component 0 over each valid box of weight.

◆ makeSFC() [1/6]

std::vector< std::vector< int > > amrex::DistributionMapping::makeSFC	(	const BoxArray &	ba,
		bool	use_box_vol = `true`,
		int	nprocs = `ParallelContext::NProcsSub()`
	)

static

if use_box_vol is true, weight boxes by their volume in Distribute otherwise, all boxes will be treated with equal weight

◆ makeSFC() [2/6]

DistributionMapping amrex::DistributionMapping::makeSFC	(	const LayoutData< Real > &	rcost_local,
		Real &	currentEfficiency,
		Real &	proposedEfficiency,
		bool	broadcastToAll = `true`,
		int	root = `ParallelDescriptor::IOProcessorNumber()`
	)

static

Computes a new distribution mapping by distributing input costs according to a space filling curve (SFC) algorithm.

Parameters

[in]	rcost_local	LayoutData of costs; contains, e.g., costs for the local boxes in the FAB array, corresponding indices in the global indices in the FAB array, and the distribution mapping
[in,out]	currentEfficiency	On the root process, this is the efficiency (i.e., mean cost over all MPI ranks, normalized to the max cost) given the current distribution mapping
[in,out]	proposedEfficiency	On the root process, this is the efficiency for the proposed distribution mapping
[in]	broadcastToAll	controls whether to transmit the proposed distribution mapping to all other processes; setting this to false allows to, e.g., test whether the proposed distribution mapping is an improvement relative to the current distribution mapping, before deciding to broadcast the proposed distribution mapping
[in]	root	which process to collect the local costs from others and compute the proposed distribution mapping

Returns: the proposed load-balanced distribution mapping

◆ makeSFC() [3/6]

DistributionMapping amrex::DistributionMapping::makeSFC	(	const MultiFab &	weight,
		bool	sort = `true`
	)

static

Build an SFC map weighted by the sum of component 0 over each valid box of weight; sort enables load-aware ordering.

◆ makeSFC() [4/6]

DistributionMapping amrex::DistributionMapping::makeSFC	(	const MultiFab &	weight,
		Real &	eff,
		bool	sort = `true`
	)

static

Build an SFC map weighted by the sum of component 0 over each valid box of weight, write efficiency to eff, and optionally use load-aware ordering.

◆ makeSFC() [5/6]

DistributionMapping amrex::DistributionMapping::makeSFC	(	const Vector< Real > &	rcost,
		const BoxArray &	ba,
		bool	sort = `true`
	)

static

Build an SFC map from rcost and ba; sort enables load-aware bucket and rank/team ordering.

◆ makeSFC() [6/6]

DistributionMapping amrex::DistributionMapping::makeSFC	(	const Vector< Real > &	rcost,
		const BoxArray &	ba,
		Real &	eff,
		bool	sort = `true`
	)

static

Build an SFC map from rcost and ba, write efficiency to eff, and optionally use load-aware ordering.

◆ operator!=()

bool amrex::DistributionMapping::operator!= ( const DistributionMapping & rhs ) const

noexcept

Are the distributions different?

◆ operator=() [1/2]

DistributionMapping & amrex::DistributionMapping::operator= ( const DistributionMapping & rhs )

default

The copy assignment operator.

◆ operator=() [2/2]

DistributionMapping & amrex::DistributionMapping::operator= ( DistributionMapping && rhs )

defaultnoexcept

The move assignment operator.

◆ operator==()

bool amrex::DistributionMapping::operator== ( const DistributionMapping & rhs ) const

noexcept

Are the distributions equal?

◆ operator[]()

int amrex::DistributionMapping::operator[] ( int index ) const

inlinenoexcept

Equivalent to ProcessorMap()[index].

◆ ProcessorMap()

const Vector< int > & amrex::DistributionMapping::ProcessorMap ( ) const

noexcept

Returns a constant reference to the mapping of boxes in the underlying BoxArray to the CPU that holds the FAB on that Box.

ProcessorMap()[i] is an integer in the interval [0, NCPU) where NCPU is the number of CPUs being used.

◆ readFrom()

std::istream & amrex::DistributionMapping::readFrom ( std::istream & is )

Read the distribution mapping from formatted text stream is.

◆ RoundRobinProcessorMap() [1/2]

void amrex::DistributionMapping::RoundRobinProcessorMap	(	const std::vector< Long > &	wgts,
		int	nprocs,
		bool	sort = `true`
	)

Build a round-robin map from a weight vector.

Parameters

wgts	Per-box weights; the vector length defines `nboxes`.
nprocs	Number of processes requested for the mapping.
sort	When true, assign boxes to ranks or teams ordered by increasing existing memory use. Boxes are always ordered by decreasing weight.

◆ RoundRobinProcessorMap() [2/2]

void amrex::DistributionMapping::RoundRobinProcessorMap	(	int	nboxes,
		int	nprocs,
		bool	sort = `true`
	)

Build a round-robin map for nboxes boxes.

Parameters

nboxes	Number of boxes.
nprocs	Number of processes requested for the mapping.
sort	When true, assign boxes to ranks or teams ordered by increasing existing memory use. Box indices remain in input order.

◆ SameRefs()

static bool amrex::DistributionMapping::SameRefs	(	const DistributionMapping &	lhs,
		const DistributionMapping &	rhs
	)

inlinestatic

Return true if lhs and rhs share the same underlying Ref.

◆ SFC_Threshold() [1/2]

int amrex::DistributionMapping::SFC_Threshold ( )

static

Return the SFC threshold; the SFC constructors fall back to knapsack when boxes.size() < threshold*nprocs.

◆ SFC_Threshold() [2/2]

void amrex::DistributionMapping::SFC_Threshold ( int n )

static

Set the SFC threshold n (clamped to >= 1); SFC ordering is used only when boxes.size() >= n*nprocs.

◆ SFCProcessorMap() [1/2]

void amrex::DistributionMapping::SFCProcessorMap	(	const BoxArray &	boxes,
		const std::vector< Long > &	wgts,
		int	nprocs,
		bool	sort = `true`
	)

Build an SFC-ordered map for boxes with per-box weights wgts.

Parameters

boxes	Boxes to distribute.
wgts	Per-box weights (e.g., cell counts).
nprocs	Number of processes requested for the mapping.
sort	When true, assign heavier SFC buckets to less-used ranks or teams. Boxes are ordered along the SFC regardless of this flag.

◆ SFCProcessorMap() [2/2]

void amrex::DistributionMapping::SFCProcessorMap	(	const BoxArray &	boxes,
		const std::vector< Long > &	wgts,
		int	nprocs,
		Real &	efficiency,
		bool	sort = `true`
	)

Build an SFC-ordered map and report the resulting efficiency.

Parameters

boxes	Boxes to distribute.
wgts	Per-box weights (e.g., cell counts).
nprocs	Number of processes requested for the mapping.
efficiency	Output load-balance efficiency in [0,1].
sort	When true, assign heavier SFC buckets to less-used ranks or teams. Boxes are ordered along the SFC regardless of this flag.

◆ size()

Long amrex::DistributionMapping::size ( ) const

inlinenoexcept

Length of the underlying processor map.

◆ strategy() [1/2]

DistributionMapping::Strategy amrex::DistributionMapping::strategy ( )

static

Return the current default DistributionMapping strategy.

◆ strategy() [2/2]

void amrex::DistributionMapping::strategy ( DistributionMapping::Strategy how )

static

Set the default DistributionMapping strategy used by the constructors.

◆ writeOn()

std::ostream & amrex::DistributionMapping::writeOn ( std::ostream & os ) const

Write the distribution mapping to formatted text stream os.

Friends And Related Symbol Documentation

◆ FabArray

template<typename T >

friend class FabArray

friend

◆ FabArrayBase

friend class FabArrayBase

friend

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

/home/runner/work/amrex/amrex/Src/Base/AMReX_DistributionMapping.H
/home/runner/work/amrex/amrex/Src/Base/AMReX_DistributionMapping.cpp

Classes

Public Types

Public Member Functions

Static Public Member Functions

Friends

Detailed Description

Member Enumeration Documentation

◆ Strategy

Constructor & Destructor Documentation

◆ DistributionMapping() [1/8]

◆ DistributionMapping() [2/8]

◆ DistributionMapping() [3/8]

◆ ~DistributionMapping()

◆ DistributionMapping() [4/8]

◆ DistributionMapping() [5/8]

◆ DistributionMapping() [6/8]

◆ DistributionMapping() [7/8]

◆ DistributionMapping() [8/8]

Member Function Documentation

◆ capacity()

◆ ComputeDistributionMappingEfficiency()

◆ ConvertCostRealToLong()

◆ define() [1/3]

◆ define() [2/3]

◆ define() [3/3]

◆ empty()

◆ Finalize()

◆ getRefID()

◆ getWeakRef()

◆ Initialize()

◆ KnapSackProcessorMap() [1/2]

◆ KnapSackProcessorMap() [2/2]

◆ linkCount()

◆ makeKnapSack() [1/5]

◆ makeKnapSack() [2/5]

◆ makeKnapSack() [3/5]

◆ makeKnapSack() [4/5]

◆ makeKnapSack() [5/5]

◆ makeRoundRobin()

◆ makeSFC() [1/6]

◆ makeSFC() [2/6]

◆ makeSFC() [3/6]

◆ makeSFC() [4/6]

◆ makeSFC() [5/6]

◆ makeSFC() [6/6]

◆ operator!=()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ operator==()

◆ operator[]()

◆ ProcessorMap()

◆ readFrom()

◆ RoundRobinProcessorMap() [1/2]

◆ RoundRobinProcessorMap() [2/2]

◆ SameRefs()

◆ SFC_Threshold() [1/2]

◆ SFC_Threshold() [2/2]

◆ SFCProcessorMap() [1/2]

◆ SFCProcessorMap() [2/2]

◆ size()

◆ strategy() [1/2]

◆ strategy() [2/2]

◆ writeOn()

Friends And Related Symbol Documentation

◆ FabArray

◆ FabArrayBase