Remove Tree dependencies (#58)

Author: ishii-norimi

lib/model/hdbscan.js

@@ -1,5 +1,3 @@
-import Tree from '../util/tree.js'
-
 /**
  * Hierarchical Density-based spatial clustering of applications with noise
  */
@@ -82,7 +80,7 @@ export default class HDBSCAN {
 
 		const tree = []
 		for (let i = 0; i < n; i++) {
-			tree[i] = new Tree({ point: datas[i], index: [i], distance: 0 })
+			tree[i] = { index: [i], distance: 0, children: [] }
 		}
 		while (tree.length > 1) {
 			let min_i = -1
@@ -107,13 +105,11 @@ export default class HDBSCAN {
 			}
 			dmreach[min_i].splice(min_j, 1)
 			dmreach.splice(min_j, 1)
-			tree[min_i] = new Tree(
-				{
-					distance: min_d,
-					index: [...tree[min_i].value.index, ...tree[min_j].value.index],
-				},
-				[tree[min_i], tree[min_j]]
-			)
+			tree[min_i] = {
+				distance: min_d,
+				index: [...tree[min_i].index, ...tree[min_j].index],
+				children: [tree[min_i], tree[min_j]],
+			}
 			tree.splice(min_j, 1)
 		}
 
@@ -122,29 +118,29 @@ export default class HDBSCAN {
 		const clusters = []
 		while (stack.length > 0) {
 			let [tree, ctree] = stack.pop()
-			ctree.index = tree.value.index
-			ctree.lbirth = 1 / tree.value.distance
+			ctree.index = tree.index
+			ctree.lbirth = 1 / tree.distance
 			ctree.stability = 0
 			ctree.children = []
 			clusters.push(ctree)
 			while (true) {
-				for (let i = tree.length - 1; i >= 0; i--) {
-					const c = tree.at(i)
-					if (c.value.index.length < this._minClusterSize) {
-						tree.removeAt(i)
-						if (c.value.distance > 0) {
-							ctree.stability += c.value.index.length * (1 / c.value.distance - ctree.lbirth)
+				for (let i = tree.children.length - 1; i >= 0; i--) {
+					const c = tree.children[i]
+					if (c.index.length < this._minClusterSize) {
+						tree.children.splice(i, 1)
+						if (c.distance > 0) {
+							ctree.stability += c.index.length * (1 / c.distance - ctree.lbirth)
 						}
 					}
 				}
-				if (tree.length === 0) {
+				if (tree.children.length === 0) {
 					break
-				} else if (tree.length === 1) {
-					tree = tree.at(0)
+				} else if (tree.children.length === 1) {
+					tree = tree.children[0]
 				} else {
-					for (let i = 0; i < tree.length; i++) {
+					for (let i = 0; i < tree.children.length; i++) {
 						const ct = {}
-						stack.push([tree.at(i), (ctree.children[i] = ct)])
+						stack.push([tree.children[i], (ctree.children[i] = ct)])
 					}
 					break
 				}