August 2017
Intermediate to advanced
360 pages
8h 35m
Chinese
Content preview from 算法技术手册（原书第2 版）
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空间树结构
｜
303
空间树结构
表
10
-
6
：稠密数据集和稀疏数据集上的 R 树删除性能结果（续）
稠密 稀疏
9 8.78 11.31 14.01 1.23 2.05 3.39
10 12.45 8.45 9.59 18.34 1.08 1.8 3.07 5.43
11 8.09 7.56 8.68 12.28 1.13 1.66 2.51 4.17
12 8.91 8.25 11.26 14.8 15.82 1.04 1.52 2.18 3.14 5.91
我们现在令
M
=
4
和
m
=
2
，然后计算在
n
不断增加时搜索和删除操作的性能。一般来说，
当删除操作数量较多时，稍大的
M
值会有所帮助，因为它可以减少未满结点的数量，从
而减少了需要重新插入
R
树中值的数量，不过真正的性能行为要根据数据以及切分结点
时所采取的平衡策略而定。结果见表
10-7
。
表
10
-
7
：随着
n
翻倍，稀疏数据集上 R 树的搜索和删除性能
n
/ 个 搜索 /ms 删除 /ms
128 0.033 0.135
256 0.060 0.162
512 0.108 0.262
1,024 0.178 0.320
2,048 0.333 0.424
4,096 0.725 0.779
8,192 1.487 1.306
16,384 3.638 2.518
32,768 7.965 3.980
65,536 16.996 10.051
131,072 33.985 15.115
10.9 参考文献
Bayer ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.