warp.hash\_grid\_query
======================

.. function:: warp._src.lang.hash_grid_query(id: uint64, point: vec3f, max_dist: float32) -> HashGridQuery

   .. hlist::
      :columns: 8

      * Kernel

   Construct a point query against a :class:`warp.HashGrid`.
   
   Returns a query that iterates over candidate neighbors of ``point``: every point in the grid
   cells overlapped by the box from ``point - max_dist`` to ``point + max_dist``. These are
   *candidates* — the grid does not test distance, so some are farther than ``max_dist``; filter
   by actual distance yourself. Advance the query and read each candidate's index with
   :func:`hash_grid_query_next`. ``point`` must be in the same coordinate space as the points the
   grid was built from (see :class:`warp.HashGrid`).
   
   :param id: The :class:`warp.HashGrid` identifier
   :param point: The query point
   :param max_dist: The query radius
   
   :returns: A hash-grid query object to pass to :func:`hash_grid_query_next`.
   
   .. rubric:: Example
   
   .. testcode::
   
       @wp.kernel
       def count_neighbors(grid_id: wp.uint64, pts: wp.array[wp.vec3], radius: wp.float32, out_count: wp.array[wp.int32]):
           i = wp.tid()
           p = pts[i]
           query = wp.hash_grid_query(grid_id, p, radius)
           index = int(0)
           n = int(0)
           while wp.hash_grid_query_next(query, index):
               if wp.length(p - pts[index]) <= radius:
                   n += 1
           out_count[i] = n
   
       points = wp.array([[0,0,0],[0.1,0,0],[0.5,0,0],[2.0,0,0]], dtype=wp.vec3)
       grid = wp.HashGrid(dim_x=8, dim_y=8, dim_z=8)
       grid.build(points=points, radius=0.3)
   
       out_count = wp.zeros(4, dtype=wp.int32)
       wp.launch(count_neighbors, dim=4, inputs=[grid.id, points, 0.3], outputs=[out_count])
       print(out_count.numpy())
   
   .. testoutput::
   
       [2 2 1 1]
   

.. function:: warp._src.lang.hash_grid_query(id: uint64, point: vec3f, max_dist: float32, group: int32) -> HashGridQuery
   :noindex:

   .. hlist::
      :columns: 8

      * Kernel

   Construct a point query against a :class:`warp.HashGrid`, restricted to one point group.
   
   Returns a query that iterates over candidate neighbors of ``point``: every point in the grid
   cells overlapped by the box from ``point - max_dist`` to ``point + max_dist``. These are
   *candidates* — the grid does not test distance, so some are farther than ``max_dist``; filter
   by actual distance yourself. Advance the query and read each candidate's index with
   :func:`hash_grid_query_next`. ``point`` must be in the same coordinate space as the points the
   grid was built from (see :class:`warp.HashGrid`).
   
   If the grid was built with groups, only points whose group id equals ``group`` are returned as
   candidates; any ``int32`` value is a valid group id. Omit the ``group`` argument to visit all
   groups, matching ungrouped behavior. Unlike grouped BVH queries, grouped hash-grid queries do
   not require a root lookup; pass the group id directly.
   
   :param id: The :class:`warp.HashGrid` identifier
   :param point: The query point
   :param max_dist: The query radius
   :param group: Restrict candidates to points built with this group id
   
   :returns: A hash-grid query object to pass to :func:`hash_grid_query_next`.
   

.. function:: warp._src.lang.hash_grid_query(id: uint64, point: vec3h, max_dist: float16) -> HashGridQuery
   :noindex:

   .. hlist::
      :columns: 8

      * Kernel

   Construct a point query against a :class:`warp.HashGrid` (float16 precision).
   
   The ``float16`` overload of :func:`hash_grid_query`. Behavior and usage match the default
   ``float32`` overload; see it for details and a usage example.
   
   :param id: The :class:`warp.HashGrid` identifier
   :param point: The query point
   :param max_dist: The query radius
   
   :returns: A hash-grid query object to pass to :func:`hash_grid_query_next`.
   

.. function:: warp._src.lang.hash_grid_query(id: uint64, point: vec3h, max_dist: float16, group: int32) -> HashGridQuery
   :noindex:

   .. hlist::
      :columns: 8

      * Kernel

   Construct a point query against a :class:`warp.HashGrid`, restricted to one point group (float16 precision).
   
   The ``float16`` overload of :func:`hash_grid_query`. Behavior and usage match the default
   ``float32`` overload; see it for details and a usage example.
   
   If the grid was built with groups, only points whose group id equals ``group`` are returned as
   candidates; any ``int32`` value is a valid group id. Omit the ``group`` argument to visit all
   groups, matching ungrouped behavior. Unlike grouped BVH queries, grouped hash-grid queries do
   not require a root lookup; pass the group id directly.
   
   :param id: The :class:`warp.HashGrid` identifier
   :param point: The query point
   :param max_dist: The query radius
   :param group: Restrict candidates to points built with this group id
   
   :returns: A hash-grid query object to pass to :func:`hash_grid_query_next`.
   

.. function:: warp._src.lang.hash_grid_query(id: uint64, point: vec3d, max_dist: float64) -> HashGridQuery
   :noindex:

   .. hlist::
      :columns: 8

      * Kernel

   Construct a point query against a :class:`warp.HashGrid` (float64 precision).
   
   The ``float64`` overload of :func:`hash_grid_query`. Behavior and usage match the default
   ``float32`` overload; see it for details and a usage example.
   
   :param id: The :class:`warp.HashGrid` identifier
   :param point: The query point
   :param max_dist: The query radius
   
   :returns: A hash-grid query object to pass to :func:`hash_grid_query_next`.
   

.. function:: warp._src.lang.hash_grid_query(id: uint64, point: vec3d, max_dist: float64, group: int32) -> HashGridQuery
   :noindex:

   .. hlist::
      :columns: 8

      * Kernel

   Construct a point query against a :class:`warp.HashGrid`, restricted to one point group (float64 precision).
   
   The ``float64`` overload of :func:`hash_grid_query`. Behavior and usage match the default
   ``float32`` overload; see it for details and a usage example.
   
   If the grid was built with groups, only points whose group id equals ``group`` are returned as
   candidates; any ``int32`` value is a valid group id. Omit the ``group`` argument to visit all
   groups, matching ungrouped behavior. Unlike grouped BVH queries, grouped hash-grid queries do
   not require a root lookup; pass the group id directly.
   
   :param id: The :class:`warp.HashGrid` identifier
   :param point: The query point
   :param max_dist: The query radius
   :param group: Restrict candidates to points built with this group id
   
   :returns: A hash-grid query object to pass to :func:`hash_grid_query_next`.