grid_space.py

## \example algebra/grid_space.py
# This example shows how to use the grid support in IMP.algebra to
# discretize a set of continuous points. In this case the points are
# simply randomly drawn from the surface of a sphere, but they could be
# taken from something more interesting.

import IMP.algebra

# create a unit grid with its origin at 0,0,0
g = IMP.algebra.SparseUnboundedIntGrid3D(1, IMP.algebra.Vector3D(0, 0, 0))

s = IMP.algebra.Sphere3D(IMP.algebra.Vector3D(1, 1, 1), 6)
count = 0
for i in range(0, 100):
    p = IMP.algebra.get_random_vector_on(s)
    ei = g.get_extended_index(p)
    if g.get_has_index(ei):
        print "hit"
    else:
        g.add_voxel(ei, count)
        count += 1

in_count = 0
for i in g.get_extended_indexes(IMP.algebra.get_bounding_box(s)):
    if IMP.algebra.get_distance(s.get_center(), g.get_center(i)) > 6:
        continue
    if g.get_has_index(i):
        print "hit"
    else:
        g.add_voxel(i, -1)
        in_count += 1

print "There are", len(g.get_all_indexes()), "distinct values", count, in_count