Minimalistic functions and types for HTM indexing. More...

#include "geometry.h"

Include dependency graph for htm.h:

This graph shows which files directly or indirectly include this file:

Data Structures
struct	htm_ids
	A sorted list of 64 bit integer ranges. More...
struct	htm_v3p
	A position and a payload. More...
struct	htm_tri
	A structure describing the geometry of an HTM triangle (aka a trixel). More...
Defines
#define	HTM_MAX_LEVEL 24
	Maximum HTM tree subdivision level.
#define	HTM_DEC_MAX_LEVEL 18
	Maximum level of a decimal index stored in a 64 bit signed integer.
Enumerations
enum	htm_root { HTM_S0 = 0, HTM_S1 = 1, HTM_S2 = 2, HTM_S3 = 3, HTM_N0 = 4, HTM_N1 = 5, HTM_N2 = 6, HTM_N3 = 7, HTM_NROOTS = 8 }
	Root triangle numbers. More...
Functions
struct htm_v3p	__attribute__ ((aligned(16)))
int64_t	htm_v3_id (const struct htm_v3 *point, int level)
	Computes an HTM ID for a position.
enum htm_errcode	htm_v3p_idsort (struct htm_v3p points, int64_t ids, size_t n, int level)
	Computes HTM IDs for a list of positions with payloads.
int	htm_level (int64_t id)
	Returns the HTM subdivision level of the given ID, or -1 if the ID is invalid.
enum htm_errcode	htm_tri_init (struct htm_tri *tri, int64_t id)
	Computes and stores the attributes of the HTM triangle with the given id.
struct htm_ids *	htm_s2circle_ids (struct htm_ids ids, const struct htm_v3 center, double radius, int level, size_t maxranges, enum htm_errcode *err)
	Returns a list of HTM ID ranges corresponding to the HTM triangles overlapping the given circle.
struct htm_ids *	htm_s2ellipse_ids (struct htm_ids ids, const struct htm_s2ellipse ellipse, int level, size_t maxranges, enum htm_errcode *err)
	Returns a list of HTM ID ranges corresponding to the HTM triangles overlapping the given ellipse.
struct htm_ids *	htm_s2cpoly_ids (struct htm_ids ids, const struct htm_s2cpoly poly, int level, size_t maxranges, enum htm_errcode *err)
	Returns a list of HTM ID ranges corresponding to the HTM triangles overlapping the given spherical convex polygon.
int64_t	htm_idtodec (int64_t id)
	Converts an HTM ID as returned by the various indexing functions to decimal form.
Variables
struct htm_v3	v
	Position.
void *	payload
	Pointer to payload.
struct htm_tri	__attribute__

Detailed Description

Minimalistic functions and types for HTM indexing.

This software is based on work by A. Szalay, T. Budavari, G. Fekete at The Johns Hopkins University, and Jim Gray, Microsoft Research. See the following links for more information:

http://voservices.net/spherical/ http://adsabs.harvard.edu/abs/2010PASP..122.1375B