Added examples for vp tree

This commit is contained in:
Adrian Mariano 2021-05-30 20:32:56 -04:00
parent bf877f3459
commit 67f08e020b

View file

@ -291,6 +291,18 @@ function _vp_tree(ptlist, ind, leafsize) =
// tree = vantage point tree from vp_tree
// p = point to search for
// r = search radius
// Example: A set of four queries to find points within 1 unit of the query. The circles show the search region and all have radius 1.
// $fn=32;
// k = 2000;
// points = array_group(rands(0,10,k*2,seed=13333),2);
// vp = vp_tree(points);
// queries = [for(i=[3,7],j=[3,7]) [i,j]];
// search_ind = [for(q=queries) vp_search(points, vp, q, 1)];
// move_copies(points) circle(r=.08);
// for(i=idx(queries)){
// color("blue")stroke(move(queries[i],circle(r=1)), closed=true, width=.08);
// color("red")move_copies(select(points, search_ind[i])) circle(r=.08);
// }
function _vp_search(points, tree, p, r) =
is_list(tree[0]) ? [for(i=tree[0]) if (norm(points[i]-p)<=r) i]
:
@ -324,6 +336,20 @@ function vp_search(points, tree, p, r) =
// tree = vantage point tree from vp_tree
// p = point to search for
// k = number of neighbors to return
// Example: Four queries to find the 15 nearest points. The circles show the radius defined by the most distant query result. Note they are different for each query.
// $fn=32;
// k = 2000;
// points = array_group(rands(0,10,k*2,seed=13333),2);
// vp = vp_tree(points);
// queries = [for(i=[3,7],j=[3,7]) [i,j]];
// search_ind = [for(q=queries) vp_nearest(points, vp, q, 15)];
// move_copies(points) circle(r=.08);
// for(i=idx(queries)){
// color("red")move_copies(select(points, search_ind[i])) circle(r=.08);
// color("blue")stroke(move(queries[i],
// circle(r=norm(points[last(search_ind[i])]-queries[i]))),
// closed=true, width=.08);
// }
function _insert_sorted(list, k, new) =
len(list)==k && new[1]>= last(list)[1] ? list
: [