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