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// Copyright ©2019 The Gonum Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package kdtree_test
import (
"fmt"
"math"
"gonum.org/v1/gonum/spatial/kdtree"
)
func ExampleTree() {
// Example data from https://en.wikipedia.org/wiki/K-d_tree
points := kdtree.Points{{2, 3}, {5, 4}, {9, 6}, {4, 7}, {8, 1}, {7, 2}}
t := kdtree.New(points, false)
q := kdtree.Point{8, 7}
p, d := t.Nearest(q)
fmt.Printf("%v is closest point to %v, d=%f\n", p, q, math.Sqrt(d))
// Output:
// [9 6] is closest point to [8 7], d=1.414214
}
func ExampleTree_bounds() {
// Example data from https://en.wikipedia.org/wiki/K-d_tree
points := kdtree.Points{{2, 3}, {5, 4}, {9, 6}, {4, 7}, {8, 1}, {7, 2}}
t := kdtree.New(points, true)
fmt.Printf("Bounding box of points is %+v\n", t.Root.Bounding)
// Output:
// Bounding box of points is &{Min:[2 1] Max:[9 7]}
}
func ExampleTree_Do() {
// Example data from https://en.wikipedia.org/wiki/K-d_tree
points := kdtree.Points{{2, 3}, {5, 4}, {9, 6}, {4, 7}, {8, 1}, {7, 2}}
// Print all points in the data set within 3 of (3, 5).
t := kdtree.New(points, false)
q := kdtree.Point{3, 5}
t.Do(func(c kdtree.Comparable, _ *kdtree.Bounding, _ int) (done bool) {
// Compare each distance and output points
// with a Euclidean distance less than 3.
// Distance returns the square of the
// Euclidean distance between points.
if q.Distance(c) <= 3*3 {
fmt.Println(c)
}
return
})
// Unordered output:
// [2 3]
// [4 7]
// [5 4]
}
func ExampleTree_DoBounded() {
// Example data from https://en.wikipedia.org/wiki/K-d_tree
points := kdtree.Points{{2, 3}, {5, 4}, {9, 6}, {4, 7}, {8, 1}, {7, 2}}
// Find all points within the bounding box ((3, 3), (6, 8))
// and print them with their bounding boxes and tree depth.
t := kdtree.New(points, true) // Construct tree with bounding boxes.
b := &kdtree.Bounding{
Min: kdtree.Point{3, 3},
Max: kdtree.Point{6, 8},
}
t.DoBounded(b, func(c kdtree.Comparable, bound *kdtree.Bounding, depth int) (done bool) {
fmt.Printf("p=%v bound=%+v depth=%d\n", c, bound, depth)
return
})
// Output:
// p=[5 4] bound=&{Min:[2 3] Max:[5 7]} depth=1
// p=[4 7] bound=&{Min:[4 7] Max:[4 7]} depth=2
}
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