d2toindex Class Reference

The box is divided into a square grid of cells. 0 1 2 .. W-1, W W+1 ... 2W-1, ... W*W-1. More...

#include <d2toindex.h>

Collaboration diagram for d2toindex:

List of all members.

Public Member Functions

d2toindex (boxcollision const &box_)

Constructor.

d2toindex (particle const *pi_, boxcollision const &box_)

~d2toindex ()

void reset ()

intc index (uintc i) const

Access the ith particle's grid index.

void getsurroundingcells (uint *&nb_, uint &sz, uintc k)

Includes k.

Public Attributes

particle const * pi

Array of particles set by the client.

boxcollision const & box

Bounding space.

uint * nb

Neighbour cells and self.

uint W

W^2 cell grid, W is set by the client.

Detailed Description

The box is divided into a square grid of cells. 0 1 2 .. W-1, W W+1 ... 2W-1, ... W*W-1.

Definition at line 26 of file d2toindex.h.

Constructor & Destructor Documentation

d2toindex::d2toindex ( boxcollision const & box_ )

Constructor.

Definition at line 6 of file d2toindex.cpp.

00009   : pi(0), box(box_), nb(new uint[9]), W(0) 
00010 {
00011 }

d2toindex::d2toindex	(	particle const *	pi_,
		boxcollision const &	box_
	)

Definition at line 15 of file d2toindex.cpp.

00019   : pi(pi_), box(box_), nb(new uint[9]), W(0) 
00020 {
00021 }

d2toindex::~d2toindex ( )

Definition at line 24 of file d2toindex.cpp.

References nb.

00025 { 
00026   delete[] nb; 
00027 }

Member Function Documentation

void d2toindex::getsurroundingcells	(	uint *&	nb_,
		uint &	sz,
		uintc	k
	)

Includes k.

Definition at line 58 of file d2toindex.cpp.

Referenced by test03().

00063 {
00064   assert(W!=0);
00065   boolc above = (k>=W);
00066   boolc left = ((k%W)!=0);
00067   boolc below = (k+W<W*W);
00068   boolc right = ((k%W)!=W-1);
00069 
00070   uint index(0);
00071 
00072   nb[index++] = k;
00073 
00074   if (left)
00075   {
00076     nb[index++] = k-1;
00077     if (above)
00078       nb[index++] = k-W-1;
00079     if (below)
00080       nb[index++] = k+W-1;
00081   }
00082 
00083   if (right)
00084   {
00085     nb[index++] = k+1;
00086     if (above)
00087       nb[index++] = k-W+1;
00088     if (below)
00089       nb[index++] = k+W+1;
00090   }
00091 
00092   if (above)
00093     nb[index++] = k-W;
00094 
00095   if (below)
00096     nb[index++] = k+W;
00097   
00098   // finish
00099   nb_ = nb;
00100   sz = index;
00101 }

intc d2toindex::index ( uintc i ) const

Access the ith particle's grid index.

Definition at line 37 of file d2toindex.cpp.

References box, pi, particle::pos, W, boxcollision::x0, and boxcollision::y0.

Referenced by test03().

00038 {
00039   assert(W!=0);
00040   assert(pi!=0);
00041 
00042   particle const & p(pi[i]);
00043   // cout << SHOW(p) << endl;
00044   //double x = (p.pos[0]-box.x0)/(box.x1-box.x0);
00045   //double y = 1.0 - (p.pos[1]-box.y0)/(box.y1-box.y0);
00046   double x = (p.pos[0]-box.x0)*xleninv; 
00047   double y = 1.0 - (p.pos[1]-box.y0)*yleninv;
00048   //cout << SHOW(x) << endl;
00049   //cout << SHOW(y) << endl;
00050   int ix = (int)(x*W) % W;
00051   int iy = (int)(y*W) % W;
00052   //cout << SHOW(ix) << endl;
00053   //cout << SHOW(iy) << endl;
00054   return ix + W*iy;
00055 }

void d2toindex::reset ( )

Definition at line 29 of file d2toindex.cpp.

References box, boxcollision::x0, boxcollision::x1, boxcollision::y0, and boxcollision::y1.

Referenced by test03().

00030 { 
00031   assert(box.x1-box.x0!=0.0);
00032   assert(box.y1-box.y0!=0.0);
00033   xleninv = 1.0/(box.x1-box.x0);
00034   yleninv = 1.0/(box.y1-box.y0);
00035 }

Member Data Documentation

boxcollision const& d2toindex::box

Bounding space.

Definition at line 37 of file d2toindex.h.

Referenced by index(), and reset().

uint* d2toindex::nb

Neighbour cells and self.

Cell surrounded by neighbour cells.
  xxx
  xox
  xxx

Definition at line 47 of file d2toindex.h.

Referenced by ~d2toindex().

particle const* d2toindex::pi

Array of particles set by the client.

Definition at line 34 of file d2toindex.h.

Referenced by index().

uint d2toindex::W

W^2 cell grid, W is set by the client.

Definition at line 50 of file d2toindex.h.

Referenced by index(), and test03().

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

nbody/d2toindex.h
nbody/d2toindex.cpp


Public Member Functions
	d2toindex (boxcollision const &box_)
	Constructor.
	d2toindex (particle const *pi_, boxcollision const &box_)
	~d2toindex ()
void	reset ()
intc	index (uintc i) const
	Access the ith particle's grid index.
void	getsurroundingcells (uint *&nb_, uint &sz, uintc k)
	Includes k.
Public Attributes
particle const *	pi
	Array of particles set by the client.
boxcollision const &	box
	Bounding space.
uint *	nb
	Neighbour cells and self.
uint	W
	W^2 cell grid, W is set by the client.