This is the HGRID class - This is the actually HGRID code. More...

#include <HGRID.h>

Public Member Functions
	HGrid ()

	HGrid (int num_buckets, double cellOverSizeRatio, std::vector< double > &cellSizes)
	constructor: initializes parameters and allocates space for internal variables More...

	~HGrid ()
	constructor: initializes parameters and allocates space for internal variables More...

void	Initialize_inv_size ()

void	InsertParticleToHgrid (BaseParticle *obj)
	This insert a particle given by CParticle in to the HGrid (i.e. it sets up the particle grid properts updates the level information on the grid) More...

int	ComputeHashBucketIndex (int x, int y, int z, int l)
	Computes hash bucket index in range [0, NUM_BUCKETS-1]. More...

int	ComputeHashBucketIndex (int x, int y, int l)
	Computes hash bucket index in range [0, NUM_BUCKETS-1]. More...

void	reset_num_buckets (int new_num_buckets)

Public Attributes
int	NUM_BUCKETS
	Number of buckets used for hashing. More...

std::vector< double >	cellSizes_

std::vector< double >	invCellSizes_

int	occupiedLevelsMask
	l-th bit of occupiedLevelsMask is 1 if level l is contains particles; initially zero (Implies max 32 hgrid levels) More...

BaseParticle **	objectBucket
	objectBucket[b] stores pointer to first element in hash bucket b; initially all NULL More...

bool *	bucketIsChecked
	bucketIsChecked[b] stores if hash bucket b is checked already; initially all zero More...

Mdouble	cellOverSizeRatio_

Detailed Description

This is the HGRID class - This is the actually HGRID code.

Definition at line 39 of file HGRID.h.

Constructor & Destructor Documentation

HGrid::HGrid ( )

Definition at line 29 of file HGRID.cc.

References bucketIsChecked, and objectBucket.

 {
     objectBucket = 0; 
     bucketIsChecked = 0;
 }

HGrid::HGrid	(	int	num_buckets,
		double	cellOverSizeRatio,
		std::vector< double > &	cellSizes
	)

constructor: initializes parameters and allocates space for internal variables

Definition at line 36 of file HGRID.cc.

References bucketIsChecked, cellOverSizeRatio_, cellSizes_, NUM_BUCKETS, and objectBucket.

 {
     NUM_BUCKETS = num_buckets;
     cellOverSizeRatio_=cellOverSizeRatio;
     
     objectBucket = new BaseParticle*[NUM_BUCKETS];
     bucketIsChecked = new bool[NUM_BUCKETS];
             
     for(int i=0;i<cellSizes.size();i++)
     {
         cellSizes_.push_back(cellSizes[i]);
         std::cout<<"Level="<<i<<" Grid size="<<cellSizes_.back()<<std::endl;
     }    
 }

HGrid::~HGrid ( )

constructor: initializes parameters and allocates space for internal variables

Definition at line 52 of file HGRID.cc.

References bucketIsChecked, and objectBucket.

               {
     if (objectBucket) { delete [] objectBucket; objectBucket=0; }
     if (bucketIsChecked) { delete [] bucketIsChecked; bucketIsChecked=0; }
 }

Member Function Documentation

int HGrid::ComputeHashBucketIndex	(	int	x,
		int	y,
		int	z,
		int	l
	)

Computes hash bucket index in range [0, NUM_BUCKETS-1].

Definition at line 93 of file HGRID.cc.

References NUM_BUCKETS.

Referenced by HGRID_2D::CheckCell(), HGRID_3D::CheckCell(), HGRID_2D::CheckCell_current(), HGRID_3D::CheckCell_current(), HGRID_2D::HGRID_RemoveParticleFromHgrid(), HGRID_3D::HGRID_RemoveParticleFromHgrid(), HGRID_2D::HGRID_UpdateParticleInHgrid(), HGRID_3D::HGRID_UpdateParticleInHgrid(), Chute::IsInsertable(), HGRID_2D::TestCell(), and HGRID_3D::TestCell().

 {
     const int h1 = 0x8da6b343; // Large multiplicative constants;
     const int h2 = 0xd8163841; // here arbitrarily chosen primes
     const int h3 = 0xcb1ab31f;
     const int h4 = 0x165667b1;
         
     int n = h1 * x + h2 * y + h3 * z + h4 * l;
     n = n % NUM_BUCKETS;
         
     if (n < 0) n += NUM_BUCKETS;
                                                         
     return n;
 }   

int HGrid::ComputeHashBucketIndex	(	int	x,
		int	y,
		int	l
	)

Computes hash bucket index in range [0, NUM_BUCKETS-1].

Definition at line 108 of file HGRID.cc.

References NUM_BUCKETS.

 {
     const int h1 = 0x8da6b343; // Large multiplicative constants;
     const int h2 = 0xd8163841; // here arbitrarily chosen primes
     const int h4 = 0x165667b1;
         
     int n = h1 * x + h2 * y + h4 * l;
     n = n % NUM_BUCKETS;
         
     if (n < 0) n += NUM_BUCKETS;
                                                         
     return n;
 }

void HGrid::Initialize_inv_size ( )

Definition at line 57 of file HGRID.cc.

References cellSizes_, and invCellSizes_.

Referenced by HGRID_base::InitBroadPhase().

 {
     invCellSizes_.clear();
     for (unsigned int level = 0; level<cellSizes_.size(); level++)
     {
         invCellSizes_.push_back(1.0/cellSizes_[level]);    
     }
 }

void HGrid::InsertParticleToHgrid ( BaseParticle * obj )

This insert a particle given by CParticle in to the HGrid (i.e. it sets up the particle grid properts updates the level information on the grid)

Definition at line 69 of file HGRID.cc.

References cellOverSizeRatio_, cellSizes_, BaseParticle::get_InteractionRadius(), occupiedLevelsMask, and BaseParticle::set_HGRID_Level().

Referenced by Chute::add_particle(), HGRID_base::HGRID_InsertParticleToHgrid(), and HGRID_base::InitBroadPhase().

 {
     // Find lowest level where object fully fits inside cell, taking RATIO into account
     Mdouble diameter = obj->get_InteractionRadius() * 2.0 ;
     unsigned int level=0;
     while(level<cellSizes_.size()&&cellSizes_[level]<=diameter * cellOverSizeRatio_)
     {
         level++;
     }
 
     if (level >= cellSizes_.size()) 
     { 
         std::cerr << "ATTENTION !!! Object is larger (d=" << diameter << ", cellOverSizeRatio=" << cellOverSizeRatio_ << ") than largest grid cell allows (" << cellSizes_.back() << ")!" << std::endl; 
         exit(-1);
     }   
     
     obj->set_HGRID_Level(level);        
     // indicate level is in use - not levels with no particles no collision detection is performed
     this->occupiedLevelsMask |= (1 << level);
 }

void HGrid::reset_num_buckets ( int new_num_buckets )

Bug:: {I don't know if this function still works since we do not use (m/c)alloc anymore}

Bug:: {I don't know if this function still works since we do not use (m/c)alloc anymore}

Definition at line 124 of file HGRID.cc.

References bucketIsChecked, NUM_BUCKETS, and objectBucket.

                                                 {
     NUM_BUCKETS=new_num_buckets;
     objectBucket = (BaseParticle**)realloc(objectBucket, NUM_BUCKETS*sizeof(BaseParticle*));
     bucketIsChecked = (bool*)realloc(bucketIsChecked, NUM_BUCKETS*sizeof(bool));
 }