Detailed Description

Multi-Core implementaion. Uses Intel TBB to perform some parallel computation.

The number of parallel threads is controlled by ConcurrencyContext.

computation of free-space intervals is done in parallel
computation of initial reachability graphs is done in parallel
computation of critical values is done in parallel thread-local copies of critical values are hold and finally reduced to a single list
computation of valid placements is done in parallel to avoid conncurrency issues, the algorithm for shortest-paths trees operates on thread-local copies
MERGE and COMBINE operations on reachability graphs (multiplication of adjacancy matrices) are parallelized
if GPGPU support is available, matrix multiplications are delegated to the GPU. This is handled transparently by frechet::reach::Graph factory methods.

Parallelisation of the decision-variant main loop was considered but discarded. See AlgorithmTopoSort for more information.

In the decision variant for curves (Alt and Godau's algorithm): computation of reachability structures (recursion) is parallelized.

Author: Peter Schäfer

Definition at line 88 of file parallel.h.

#include <parallel.h>

Inherits frechet::poly::AlgorithmSingleCore.

Inherited by frechet::poly::AlgorithmTopoSort.

Public Member Functions
	AlgorithmMultiCore ()
	default constructor More...

virtual	~AlgorithmMultiCore ()
	destructor More...

virtual void	triangulate () override
	re-implements base class method; stores thread-local copies of Q's triangulation More...

Public Member Functions inherited from frechet::poly::AlgorithmSingleCore
	AlgorithmSingleCore ()

Public Member Functions inherited from frechet::poly::Algorithm
	Algorithm ()
	default constructor More...

virtual	~Algorithm ()
	destructor; releases all memory More...

Status	status () const
	current status of the algorithm More...

bool	canDecidePoly () const
	check if we can execute the decision variant on simple polygons (Buchin et al.'s algorithm) More...

bool	canOptimisePoly () const
	check if we can execute the optimisation variant on simple polygons (Buchin et al.'s algorithm) More...

bool	canOptimiseCurve () const
	check if we can execute the optimisation variant on curves (Alt and Godau's algorithm) More...

const Segments &	c_diagonals () const
	the c-diagonals More...

bool	is_c_diagonal (int di, int dj) const
	check, whether a diagonal is a c-diagonal More...

bool	is_c_diagonal (Segment s) const
	check, whether a diagonal is a c-diagonal More...

Triangulation &	PTriangulation ()
	the triangulation of P More...

Triangulation &	QTriangulation ()
	the triangulation of Q More...

Triangulation &	displayPTriangulation ()
	a complete triangulation for P (only needed for visualisation More...

const Curve &	Pcurve () const
	the first input curve P More...

const Curve &	Qcurve () const
	the first input curve Q More...

PolygonUtilities *	polygonUtilities (bool primary)
	helper object for polygon analysis More...

Status	setup (Curve &aP, Curve &aQ, bool fixOrientation=false)
	Initialize input curves and perform some basic sanity checks. More...

bool	decompose (bool optimal)
	decompose polygons into convex parts More...

void	swap ()
	swap input curves. The algorithm by Buchin et al. chooses the smalled convex decompositioin as P. More...

GraphPtr	decidePolygon (FreeSpace::ptr fs, reach::FSPath::ptr path, double epsilon, bool update_status)
	execute the decision variant for simple polygons (Buchin et al.'s algorithm) More...

double	optimisePolygon (reach::FSPath::ptr path, double approximation=0.0)
	execute the optimisaion variant for simple polygons. (Buchin et al.'s algorithm) The result value is broadcast by signal optimisationResult(double epsilon). More...

reach::Pointer	decideCurve (FreeSpace::ptr fs, reach::FSPath::ptr path, double ignored, bool update_status)
	execute the decision variant for curves. (Alt and Godau's algorithm) More...

double	optimiseCurve (double approximation=0.0)
	execute the optimisation variant for curves. (Alt and Godau's algorithm) More...

void	collectCriticalValues (bool a, bool b, bool c, bool d)
	compute a set of critical values for the optimisation variant More...

template<typename R >
int	binarySearch (const std::vector< double > &values, int lo, int hi, R(Algorithm::*decideFunction)(FreeSpace::ptr, reach::FSPath::ptr, double, bool), R &result)

template<typename R >
double	intervalSearch (double lower_bound, double upper_bound, double precision, R(Algorithm::*decideFunction)(FreeSpace::ptr, reach::FSPath::ptr, double, bool), R &result)

template<typename Float >
Float	segment_distance (const QLineF &segment, const Point &q1)

template<typename Float >
Float	bisector_distance (const Float &p1x, const Float &p1y, const Float &p2x, const Float &p2y, const Float &q1x, const Float &q1y, const Float &q2x, const Float &q2y, const Float &tolerance)

template<typename Float >
Float	bisector_distance (const Point &q1, const Point &q2, const QLineF &segment, Float tolerance)

Protected Member Functions
virtual void	calculateReachabilityGraphs () override

virtual void	calculateValidPlacements (double epsilon) override
	calculate all valid placements More...

virtual CriticalValueList &	currentCriticalValueList ()
	thread-local copy of critical values More...

virtual void	collectCriticalValues_b (const Curve &P, const Curve &Q) override
	compute critical values of type (b) More...

virtual void	collectCriticalValues_c (const Curve &P, const Curve &Q) override
	compute critical values of type (c) More...

virtual void	collectCriticalValues_d () override
	compute critical values for diagonals and reflex vertices More...

virtual void	combineCriticalValues () override
	reduce thread-local lists to a global list, then sort it More...

void	clear_qtri ()
	release thread-local variables More...

Protected Member Functions inherited from frechet::poly::AlgorithmSingleCore
virtual reach::Graph::ptr	CRG (int i, int j, Triangulation::Edge e=Triangulation::Edge())
	get a memoised Combined Reachabilty Graph. This is one of the steps in Buchin et al.'s decision algorithm. More...

virtual reach::Graph::ptr	create_RG (int i)
	compute an initial Reachabilty Graph. More...

virtual reach::Graph::ptr	create_CRG (int i, int j, Triangulation::Edge e)
	compute a Combined Reachabilty Graph. More...

virtual reach::Graph::ptr	MERGE_inner (const reach::Graph::ptr A, const reach::Graph::ptr B)

virtual reach::Graph::ptr	MERGE_outer (const reach::Graph::ptr A, const reach::Graph::ptr B)
	perform the final MERGE operation on two Reachability Graphs More...

virtual void	COMBINE (reach::Graph::ptr A, int di, int dj)

virtual GraphPtr	findFeasiblePath () override
	the main loop of Buchin et al's decision algorithm. More...

virtual bool	isSolution (GraphPtr G)

bool	assertReachabilityGraphs ()
	debug assertion; check if the CRGs are correctyl aligned More...

Protected Member Functions inherited from frechet::poly::Algorithm
GraphPtr	getValidPlacements (int di, int dj)
	get valid placements for a given pair of diagonal end points; compute them, if necssary. Subsequent calls retrieve the memo-ized result. More...

GraphPtr	calculate_RG (int i)
	get a Reachability Graph; compute it, if necessary. Subsequent calls retrieve the memo-ized result. More...

int	mapKey (int di, int dj)
	hash key for memo-ized maps More...

GraphPtr	createValidPlacementGraph (int di, int dj)
	compute an adjacancy matrix of valid placements for one pair of diagonal end points More...

void	calculateValidPlacements (poly::PolygonShortestPathsFS &spt, double epsilon, int di, int dj)
	calculate valid placements for a pair of diagonal end points More...

Triangulation::Edge	diagonalEdge (int i) const
	a diagonal edge of the triangulation of P More...

int	l () const
	number of diagonal end points More...

int	k () const
	number of c-diagonals More...

int	d (int i) const
	map a diagonal end-point to a vertex in P More...

int	partitions () const
	number of convex partitions (components) More...

void	calculatePlacements (int i, frechet::reach::Placements &result)
	calculate free-space placements More...

Status	setStatus (Status)
	set current status More...

Status	setInitialStatus (Status)
	set initial status (after pre-processing input data) More...

virtual void	cleanup ()
	release memory (meoisation maps, etc.) More...

void	updatePath (reach::FSPath::ptr path, GraphPtr result, double epsilon)
	compute a feasible path from the result of (Buchin et al.'s) decision algorithm More...

void	updatePath (reach::FSPath::ptr path, reach::Pointer startPointer, double epsilon)
	compute a feasible path from the result of (Alt and Godau's) decision algorithm More...

void	collectCriticalValues_a ()
	compute critical values of type (a) More...

void	collectCriticalValues_b (const Point &p, const Curve &Q)
	compute critical values of type (b) More...

void	collectCriticalValues_c (const QLineF &pseg, const Curve &Q)
	compute critical values of type (c) More...

void	collectCriticalValues_d (const QLineF &diagonal)
	compute critical values for diagonals and reflex vertices More...

virtual void	collectCriticalValue (const accurate_float &x)
	store a critical value. Duplicates are accepted but removed later. More...

void	removeDuplicates (CriticalValueList &vector)
	remove duplicates from a sorted list of critical values More...

template<typename R >
int	binarySearch (const std::vector< double > &values, int lo, int hi, R(Algorithm::*decideFunction)(FreeSpace::ptr, reach::FSPath::ptr, double, bool), R &result)
	perform a binary search on a list of critical values. For each step of the binary search, perform the decision variant. More...

template<typename R >
double	intervalSearch (double lower_bound, double upper_bound, double precision, R(Algorithm::*decideFunction)(FreeSpace::ptr, reach::FSPath::ptr, double, bool), R &result)
	perform a nested interval search. For each step of the search, perform the decision variant. More...

void	testCancelFlag ()
	poll cancelFlag More...

Static Protected Member Functions
static const CriticalValueList &	combine (CriticalValueList &a, const CriticalValueList &b)
	reduce two thread-local lists of critical values; the lists are simply appended More...

Static Protected Member Functions inherited from frechet::poly::Algorithm
template<typename Float >
static Float	bisector_distance (const Float &p1x, const Float &p1y, const Float &p2x, const Float &p2y, const Float &q1x, const Float &q1y, const Float &q2x, const Float &q2y, const Float &tolerance)
	compute the distance between a bisector and a polygon segment More...

template<typename Float >
static Float	segment_distance (const QLineF &segment, const Point &q1)
	compute the distance between a polygon segment and a point More...

template<typename Float >
static Float	bisector_distance (const Point &q1, const Point &q2, const QLineF &segment, Float tolerance=0.0)
	compute the distance between a bisector and a polygon segment More...

Private Types
typedef tbb::enumerable_thread_specific< Triangulation * >	LocalTriangulation

typedef tbb::combinable< CriticalValueList >	LocalCriticalValueList

typedef tbb::enumerable_thread_specific< PolygonShortestPathsFS * >	LocalSPT

Private Attributes
std::vector< Segment >	c_diagonals_vector
	vector of c-diagonals More...

Static Private Attributes
static LocalTriangulation	qtri
	thread-local copies of Q->triangulation More...

static LocalCriticalValueList	localCriticalValues
	thread-local copies of critical values More...

static LocalSPT	spt
	thread-local copies for PolygonShortestPathsFS More...

Additional Inherited Members
Public Types inherited from frechet::poly::Algorithm
enum	Status : int8_t { RUNNING = -2, RUNNING_DECIDE_POLY =-8, RUNNING_OPT_POLY =-7, RUNNING_APPROX_POLY =-6, RUNNING_DECIDE_CURVE =-5, RUNNING_OPT_CURVE =-4, RUNNING_APPROX_CURVE =-3, YES =0, NO, NOT_SET_UP, SET_UP, P_EMPTY, Q_EMPTY, P_NOT_CLOSED, Q_NOT_CLOSED, P_NOT_SIMPLE, Q_NOT_SIMPLE, P_NOT_COUNTER_CLOCKWISE, Q_NOT_COUNTER_CLOCKWISE, P_CONVEX, Q_CONVEX }
	indicates the current status of the algorithm. Negative values indicate that the algorithm is currently computing. Positive values indicate the result and also conditions of input data. More...

typedef frechet::reach::Graph::ptr	GraphPtr
	the result of the decision algorithm is a reachability Graph containing a feasible path More...

typedef boost::shared_ptr< Algorithm >	ptr
	(smart) pointer to an Algorithm object More...

Public Slots inherited from frechet::poly::Algorithm
void	resetStatus (bool stopping=false)
	reset the status of the algorithm More...

Signals inherited from frechet::poly::Algorithm
void	statusChanged ()
	emitted whenever the status of the algorithm changes. More...

void	pathUpdated (bool valid)
	emitted when a feasible path has been found More...

void	optimisationResult (double epsilon)
	emitted when the optimisation (or approximation) algorithm finds a result More...

Static Public Member Functions inherited from frechet::poly::Algorithm
static double	pickIntervalPoint (const Interval &j, int m=INT_MAX)
	pick a point from a free-space interval. Helper function for creating feasible paths. More...

Protected Types inherited from frechet::poly::Algorithm
typedef tbb::concurrent_unordered_map< int, GraphPtr >	PlacementMap
	hash map for reachability graphs More...

typedef std::vector< reach::Placements >	PlacementVector
	list of valid placements More...

typedef tbb::concurrent_unordered_map< int, reach::Graph::ptr >	GraphMap
	used to store intermediate (memo-ized) reachability graphs More...

typedef std::vector< double >	CriticalValueList
	a list of critical values More...

Protected Attributes inherited from frechet::poly::Algorithm
enum Status	_status
	current status of the algorithm More...

enum Status	initial_status
	initial status of the algorithm (before or after processing input data) More...

struct frechet::poly::Algorithm::CurveData *	P

struct frechet::poly::Algorithm::CurveData *	Q

FreeSpace::ptr	fs
	current Free-Space diagram (passed to the decision variant) More...

PlacementVector	_placements
	list of placements (for each end point of diagonals) More...

PlacementMap	_validPlacements
	map of valid placements (as adjacency matrices, for each c-diagonal) More...

reach::GraphModel::ptr	graphModel
	map free-space interval to nodes of the reachability graph More...

GraphMap	CRG_map
	a map of memo-ized Combined Reachability Graphs More...

FreeSpace::ptr	local_fs
	Free-Space used during binary searches (optimisation variant) More...

CriticalValueList	criticalValues
	the list of critical values (optimisation variant) More...

volatile bool *	cancelFlag
	indicates user interruption More...

Member Typedef Documentation

◆ LocalCriticalValueList

typedef tbb::combinable<CriticalValueList> frechet::poly::AlgorithmMultiCore::LocalCriticalValueList

private

Definition at line 96 of file parallel.h.

◆ LocalSPT

typedef tbb::enumerable_thread_specific<PolygonShortestPathsFS*> frechet::poly::AlgorithmMultiCore::LocalSPT

private

Definition at line 100 of file parallel.h.

◆ LocalTriangulation

typedef tbb::enumerable_thread_specific<Triangulation*> frechet::poly::AlgorithmMultiCore::LocalTriangulation

private

Definition at line 90 of file parallel.h.

Constructor & Destructor Documentation

◆ AlgorithmMultiCore()

AlgorithmMultiCore::AlgorithmMultiCore ( )

default constructor

Definition at line 29 of file parallel.cpp.

◆ ~AlgorithmMultiCore()

AlgorithmMultiCore::~AlgorithmMultiCore ( )

virtual

destructor

Definition at line 40 of file parallel.cpp.

Member Function Documentation

◆ calculateReachabilityGraphs()

void AlgorithmMultiCore::calculateReachabilityGraphs ( )

overrideprotectedvirtual

Now with a parallel for loop. Note that writes to _RG_map are independent, no concurrency problems.

Reimplemented from frechet::poly::AlgorithmSingleCore.

Definition at line 98 of file parallel.cpp.

◆ calculateValidPlacements()

void AlgorithmMultiCore::calculateValidPlacements ( double epsilon )

overrideprotectedvirtual

calculate all valid placements

Parameters

epsilon free-space epsilon

Reimplemented from frechet::poly::AlgorithmSingleCore.

Definition at line 155 of file parallel.cpp.

◆ clear_qtri()

void AlgorithmMultiCore::clear_qtri ( )

protected

release thread-local variables

Definition at line 47 of file parallel.cpp.

◆ collectCriticalValues_b()

void AlgorithmMultiCore::collectCriticalValues_b	(	const Curve &	P,
		const Curve &	Q
	)

overrideprotectedvirtual

compute critical values of type (b)

Parameters

P	first input curve P
Q	second curve Q

Reimplemented from frechet::poly::AlgorithmSingleCore.

Definition at line 145 of file optimise.cpp.

◆ collectCriticalValues_c()

void AlgorithmMultiCore::collectCriticalValues_c	(	const Curve &	P,
		const Curve &	Q
	)

overrideprotectedvirtual

compute critical values of type (c)

Parameters

P	first input curve P
Q	second curve Q

Reimplemented from frechet::poly::AlgorithmSingleCore.

Definition at line 185 of file optimise.cpp.

◆ collectCriticalValues_d()

void AlgorithmMultiCore::collectCriticalValues_d ( )

overrideprotectedvirtual

compute critical values for diagonals and reflex vertices

Reimplemented from frechet::poly::AlgorithmSingleCore.

Definition at line 238 of file optimise.cpp.

◆ combine()

const AlgorithmMultiCore::CriticalValueList & AlgorithmMultiCore::combine	(	CriticalValueList &	a,
		const CriticalValueList &	b
	)

staticprotected

reduce two thread-local lists of critical values; the lists are simply appended

Parameters

a	a list
b	another list

Returns: reference to a, after appending b

Definition at line 100 of file optimise.cpp.

◆ combineCriticalValues()

void AlgorithmMultiCore::combineCriticalValues ( )

overrideprotectedvirtual

reduce thread-local lists to a global list, then sort it

Reimplemented from frechet::poly::AlgorithmSingleCore.

Definition at line 71 of file optimise.cpp.

◆ currentCriticalValueList()

Algorithm::CriticalValueList & AlgorithmMultiCore::currentCriticalValueList ( )

protectedvirtual

thread-local copy of critical values

Reimplemented from frechet::poly::Algorithm.

Definition at line 33 of file optimise.cpp.

◆ triangulate()

void AlgorithmMultiCore::triangulate ( )

overridevirtual

re-implements base class method; stores thread-local copies of Q's triangulation

Reimplemented from frechet::poly::Algorithm.

Definition at line 63 of file parallel.cpp.

Member Data Documentation

◆ c_diagonals_vector

std::vector<Segment> frechet::poly::AlgorithmMultiCore::c_diagonals_vector

private

vector of c-diagonals

Definition at line 94 of file parallel.h.

◆ localCriticalValues

AlgorithmMultiCore::LocalCriticalValueList AlgorithmMultiCore::localCriticalValues

staticprivate

thread-local copies of critical values

Definition at line 98 of file parallel.h.

◆ qtri

AlgorithmMultiCore::LocalTriangulation AlgorithmMultiCore::qtri

staticprivate

thread-local copies of Q->triangulation

Definition at line 92 of file parallel.h.

◆ spt

AlgorithmMultiCore::LocalSPT AlgorithmMultiCore::spt

staticprivate

thread-local copies for PolygonShortestPathsFS

Definition at line 102 of file parallel.h.

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

include/frechet/poly/parallel.h
src/frechet/poly/optimise.cpp
src/frechet/poly/parallel.cpp

Detailed Description

Public Member Functions

Protected Member Functions

Static Protected Member Functions

Private Types

Private Attributes

Static Private Attributes

Additional Inherited Members

Member Typedef Documentation

◆ LocalCriticalValueList

◆ LocalSPT

◆ LocalTriangulation

Constructor & Destructor Documentation

◆ AlgorithmMultiCore()

◆ ~AlgorithmMultiCore()

Member Function Documentation

◆ calculateReachabilityGraphs()

◆ calculateValidPlacements()

◆ clear_qtri()

◆ collectCriticalValues_b()

◆ collectCriticalValues_c()

◆ collectCriticalValues_d()

◆ combine()

◆ combineCriticalValues()

◆ currentCriticalValueList()

◆ triangulate()

Member Data Documentation

◆ c_diagonals_vector

◆ localCriticalValues

◆ qtri

◆ spt