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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 }