kd樹的實現(python)
阿新 • • 發佈:2019-01-07
當前的實現針對的是二維空間, 程式碼可執行
T = np.array([(2,3),(5,4),(9,6),(4,7),(8,1),(7,2)])
#T = np.array([(3,3),(2,2),(1,2)])
#plt.scatter(T[:,0], T[:,1])
def crt_tree(T, i):
if len(T)==1:
return Node(T[0])
if len(T)==0:
return None
dim = T.shape[1]
axis = i % dim
#T空間的中間個數
midPos = T.shape[0 ]//2
#T的從大到小的專案的排列的索引
indices = T[:,axis].argsort(0)
midItemPos = indices[T.shape[0]//2]
node = Node(T[midItemPos])
leftT = T[indices[:midPos]]
rightT = T[indices[midPos+1:]]
node.left = crt_tree(leftT, i+1)
node.right = crt_tree(rightT, i+1)
return node
t = crt_tree(T, 0 )
pre_traversal(t)
print(T)
print(T.argsort(0))