Welcome to boxtree’s documentation!¶

boxtree is a package that, given some point locations in two or three dimensions, sorts them into an adaptive quad/octree of boxes, efficiently, in parallel, using OpenCL. It also computes geometric lookup tables and generates FMM interaction lists.

Other places on the web to find boxtree stuff:

Now you obviously want to watch the library do something (at least mildly) cool? Well, sit back and watch:

import logging

import numpy as np

import pyopencl as cl
import pytools.obj_array as obj_array


logging.basicConfig(level="INFO")

ctx = cl.create_some_context()
queue = cl.CommandQueue(ctx)

dims = 2
nparticles = 500

# -----------------------------------------------------------------------------
# generate some random particle positions
# -----------------------------------------------------------------------------
from pyopencl.clrandom import PhiloxGenerator


rng = PhiloxGenerator(ctx, seed=15)


particles = obj_array.new_1d([
    rng.normal(queue, nparticles, dtype=np.float64)
    for i in range(dims)])

# -----------------------------------------------------------------------------
# build tree and traversals (lists)
# -----------------------------------------------------------------------------
from boxtree import TreeBuilder


tb = TreeBuilder(ctx)
tree, _ = tb(queue, particles, max_particles_in_box=5)

from boxtree.traversal import FMMTraversalBuilder


tg = FMMTraversalBuilder(ctx)
trav, _ = tg(queue, tree)

This file is included in the boxtree distribution as examples/demo.py. With some plotting code (not shown above, but included in the demo file), you can see what’s going on:

_images/tree.png

More importantly, perhaps, than being able to draw the tree, the boxtree.Tree data structure is now accessible via the tree variable above, and the connectivity information needed for an FMM-like traversal is available in trav as a boxtree.traversal.FMMTraversalInfo.

Overview¶

Indices and tables¶