APIs related to spatial indexing. More...

Classes
struct	cuspatial::point_quadtree

struct	cuspatial::point_quadtree_ref

Functions
template<class PointIterator , class T = typename cuspatial::iterator_value_type<PointIterator>>
std::pair< rmm::device_uvector< uint32_t >, point_quadtree >	cuspatial::quadtree_on_points (PointIterator points_first, PointIterator points_last, vec_2d< T > vertex_1, vec_2d< T > vertex_2, T scale, int8_t max_depth, int32_t max_size, rmm::cuda_stream_view stream=rmm::cuda_stream_default, rmm::device_async_resource_ref mr=rmm::mr::get_current_device_resource())
	Construct a quadtree structure from points.

std::pair< std::unique_ptr< cudf::column >, std::unique_ptr< cudf::table > >	cuspatial::quadtree_on_points (cudf::column_view const &x, cudf::column_view const &y, double x_min, double x_max, double y_min, double y_max, double scale, int8_t max_depth, cudf::size_type max_size, rmm::device_async_resource_ref mr=rmm::mr::get_current_device_resource())
	Construct a quadtree structure from points.

Detailed Description

APIs related to spatial indexing.

Function Documentation

std::pair< std::unique_ptr< cudf::column >, std::unique_ptr< cudf::table > > cuspatial::quadtree_on_points	(	cudf::column_view const &	x,
		cudf::column_view const &	y,
		double	x_min,
		double	x_max,
		double	y_min,
		double	y_max,
		double	scale,
		int8_t	max_depth,
		cudf::size_type	max_size,
		rmm::device_async_resource_ref	mr = rmm::mr::get_current_device_resource() )

Construct a quadtree structure from points.

See also: http://www.adms-conf.org/2019-camera-ready/zhang_adms19.pdf for details.

Note: scale is applied to (x - x_min) and (y - y_min) to convert coordinates into a Morton code in 2D space.; max_depth should be less than 16, since Morton codes are represented as uint32_t. The eventual number of levels may be less than max_depth if the number of points is small or max_size is large.; All intermediate quadtree nodes will have fewer than max_size number of points. Leaf nodes are permitted (but not guaranteed) to have >= max_size number of points.

Parameters

x	Column of x-coordinates for each point.
y	Column of y-coordinates for each point.
x_min	The lower-left x-coordinate of the area of interest bounding box.
x_max	The upper-right x-coordinate of the area of interest bounding box.
y_min	The lower-left y-coordinate of the area of interest bounding box.
y_max	The upper-right y-coordinate of the area of interest bounding box.
scale	Scale to apply to each x and y distance from x_min and y_min.
max_depth	Maximum quadtree depth.
max_size	Maximum number of points allowed in a node before it's split into 4 leaf nodes.
mr	The optional resource to use for output device memory allocations.

Exceptions

cuspatial::logic_error If the x and y column sizes are different

Returns: Pair of INT32 column of sorted keys to point indices, and cudf table with five columns for a complete quadtree: key - UINT32 column of quad node keys level - UINT8 column of quadtree levels is_internal_node - BOOL8 column indicating whether the node is a quad (true) or leaf (false) length - UINT32 column for the number of child nodes (if is_internal_node), or number of points offset - UINT32 column for the first child position (if is_internal_node), or first point position

template<class PointIterator , class T = typename cuspatial::iterator_value_type<PointIterator>>

std::pair< rmm::device_uvector< uint32_t >, point_quadtree > cuspatial::quadtree_on_points	(	PointIterator	points_first,
		PointIterator	points_last,
		vec_2d< T >	vertex_1,
		vec_2d< T >	vertex_2,
		T	scale,
		int8_t	max_depth,
		int32_t	max_size,
		rmm::cuda_stream_view	stream = rmm::cuda_stream_default,
		rmm::device_async_resource_ref	mr = rmm::mr::get_current_device_resource() )

Construct a quadtree structure from points.

See also: http://www.adms-conf.org/2019-camera-ready/zhang_adms19.pdf for details.

Note: 2D coordinates are converted into a 1D Morton code by dividing each x/y by the scale: ((x - min_x) / scale and (y - min_y) / scale).; max_depth should be less than 16, since Morton codes are represented as uint32_t. The eventual number of levels may be less than max_depth if the number of points is small or max_size is large.; All intermediate quadtree nodes will have fewer than max_size number of points. Leaf nodes are permitted (but not guaranteed) to have >= max_size number of points.

Template Parameters

PointIterator	Iterator over x/y points. Must meet the requirements of LegacyRandomAccessIterator and be device-accessible.
T	the floating-point coordinate value type of the input x/y points.

Parameters

points_first	Iterator to the beginning of the range of (x, y) points.
points_last	Iterator to the end of the range of (x, y) points.
vertex_1	Vertex of the area of interest bounding box
vertex_2	Vertex of the area of interest bounding box opposite `vertex_1`
scale	Scale to apply to each x and y distance from min.x and min.y.
max_depth	Maximum quadtree depth.
max_size	Maximum number of points allowed in a node before it's split into 4 leaf nodes.
stream	The CUDA stream on which to perform computations
mr	The optional resource to use for output device memory allocations.

Returns: Pair of UINT32 column of sorted keys to point indices and a point_quadtree

Precondition: Point iterators must have the same vec_2d value type, with the same underlying floating-point coordinate type (e.g. cuspatial::vec_2d<float>).