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Heavy refactoring suggestion #2

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5dce613
Interface improved to support Distance and PlaneDistance functions, w…
Hiyorimi Feb 7, 2019
5d4a72a
Heavy refactoring to allow easy project import: removed redundant pac…
Hiyorimi Feb 7, 2019
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25 changes: 8 additions & 17 deletions kdtree.go
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Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,6 @@ import (
"math"
"sort"

"github.com/kyroy/kdtree/kdrange"
"github.com/kyroy/priority-queue"
)

Expand All @@ -32,6 +31,10 @@ type Point interface {
Dimensions() int
// Dimension returns the value of the i-th dimension.
Dimension(i int) float64
// Distance returns the distance between two points.
Distance(p Point) float64
// PlaneDistance returns the distance between the point and the plane X_{dim}=val.
PlaneDistance(val float64, dim int) float64
}

// KDTree represents the k-d tree.
Expand Down Expand Up @@ -138,7 +141,7 @@ func (t *KDTree) KNN(p Point, k int) []Point {
// RangeSearch returns all points in the given range r.
//
// Returns an empty slice when input is nil or len(r) does not equal Point.Dimensions().
func (t *KDTree) RangeSearch(r kdrange.Range) []Point {
func (t *KDTree) RangeSearch(r kdrangeRange) []Point {
if t.root == nil || r == nil || len(r) != t.root.Dimensions() {
return []Point{}
}
Expand Down Expand Up @@ -168,15 +171,15 @@ func knn(p Point, k int, start *node, currentAxis int, nearestPQ *pq.PriorityQue
// 2. move up
currentAxis = (currentAxis - 1 + p.Dimensions()) % p.Dimensions()
for path, currentNode = popLast(path); currentNode != nil; path, currentNode = popLast(path) {
currentDistance := distance(p, currentNode)
currentDistance := p.Distance(currentNode.Point)
checkedDistance := getKthOrLastDistance(nearestPQ, k-1)
if currentDistance < checkedDistance {
nearestPQ.Insert(currentNode, currentDistance)
checkedDistance = getKthOrLastDistance(nearestPQ, k-1)
}

// check other side of plane
if planeDistance(p, currentNode.Dimension(currentAxis), currentAxis) < checkedDistance {
if p.PlaneDistance(currentNode.Dimension(currentAxis), currentAxis) < checkedDistance {
var next *node
if p.Dimension(currentAxis) < currentNode.Dimension(currentAxis) {
next = currentNode.Right
Expand All @@ -189,18 +192,6 @@ func knn(p Point, k int, start *node, currentAxis int, nearestPQ *pq.PriorityQue
}
}

func distance(p1, p2 Point) float64 {
sum := 0.
for i := 0; i < p1.Dimensions(); i++ {
sum += math.Pow(p1.Dimension(i)-p2.Dimension(i), 2.0)
}
return math.Sqrt(sum)
}

func planeDistance(p Point, planePosition float64, dim int) float64 {
return math.Abs(planePosition - p.Dimension(dim))
}

func popLast(arr []*node) ([]*node, *node) {
l := len(arr) - 1
if l < 0 {
Expand Down Expand Up @@ -368,7 +359,7 @@ func (n *node) FindLargest(axis int, largest *node) *node {
return largest
}

func (n *node) RangeSearch(r kdrange.Range, axis int) []Point {
func (n *node) RangeSearch(r kdrangeRange, axis int) []Point {
points := []Point{}

for dim, limit := range r {
Expand Down
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