peano.h File Reference

#include <stddef.h>
#include <stdint.h>

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Macros
#define	BITS_PER_DIMENSION   21 /* for Peano-Hilbert order. Note: Maximum is 10 to fit in 32-bit integer ! */
#define	PEANOCELLS   (((peano_t)1)<<(3*BITS_PER_DIMENSION))
#define	DomainFac(len)   ( 1.0 / (len) * (((peano_t) 1) << (BITS_PER_DIMENSION)))

Typedefs
typedef uint64_t	peano_t

Functions
peano_t	peano_hilbert_key (int x, int y, int z, int bits)
static peano_t	PEANO (double *Pos, double BoxSize)
void	mysort_peano (void *b, size_t n, size_t s, int(*cmp)(const void *, const void *))
void	init_peano_map (void)

Macro Definition Documentation

BITS_PER_DIMENSION

#define BITS_PER_DIMENSION   21 /* for Peano-Hilbert order. Note: Maximum is 10 to fit in 32-bit integer ! */

Definition at line 9 of file peano.h.

DomainFac

#define DomainFac

(

len

)

( 1.0 / (len) * (((peano_t) 1) << (BITS_PER_DIMENSION)))

Definition at line 22 of file peano.h.

PEANOCELLS

#define PEANOCELLS   (((peano_t)1)<<(3*BITS_PER_DIMENSION))

Definition at line 10 of file peano.h.

Typedef Documentation

peano_t

typedef uint64_t peano_t

Definition at line 7 of file peano.h.

Function Documentation

init_peano_map()

void init_peano_map

(

void

)

mysort_peano()

void mysort_peano	(	void *	b,
		size_t	n,
		size_t	s,
		int(*)(const void *, const void *)	cmp
	)

PEANO()

static peano_t PEANO ( double *  Pos, double  BoxSize  )

inlinestatic

Definition at line 14 of file peano.h.

{
    /*No reason known for the Box/2000 and 1.001 factors*/
    const double DomainFac = 1.0 / (BoxSize*1.001) * (((peano_t) 1) << (BITS_PER_DIMENSION));
    const double spos[3] = {Pos[0] + BoxSize/2000, Pos[1] + BoxSize/2000, Pos[2] + BoxSize/2000};
    return peano_hilbert_key(spos[0]*DomainFac, spos[1]*DomainFac, spos[2]*DomainFac, BITS_PER_DIMENSION);
}

References BITS_PER_DIMENSION, DomainFac, and peano_hilbert_key().

Referenced by do_density_test(), do_force_test(), do_tree_test(), init(), real_drift_particle(), and setup_particles().

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peano_hilbert_key()

peano_t peano_hilbert_key	(	int	x,
		int	y,
		int	z,
		int	bits
	)

This function computes a Peano-Hilbert key for an integer triplet (x,y,z), with x,y,z in the range between 0 and 2^bits-1.

Definition at line 119 of file peano.c.

{
    int mask;
    unsigned char rotation = 0;
    peano_t key = 0;
 
    for(mask = 1 << (bits - 1); mask > 0; mask >>= 1)
    {
        unsigned char pix = ((x & mask) ? 4 : 0) | ((y & mask) ? 2 : 0) | ((z & mask) ? 1 : 0);
 
        key <<= 3;
        key |= subpix3[rotation][pix];
        rotation = rottable3[rotation][pix];
    }
 
    return key;
}

References rottable3, and subpix3.

Referenced by force_create_node_for_topnode(), and PEANO().

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