interpoint distances

1. Inter-point distances are sometimes computed within one set of points, or between two sets. So a tool must handle either case.

2. Efficiency is important, but a common method for inter-point (Euclidean) distances uses a trick that results in a loss of accuracy. The good thing is bsxfun allows us to compute distances both efficiently and accurately.

3. Many times we wish to compute an inter-point, but we only need some subset of the entire matrix. Then it might be nice to have a list of only the single nearest neighbor for each point in our set, or only the large or small distances beyond some limit.

4. Where appropriate, a sparse distance matrix might be useful.

5. Really large problems can sometimes be solved by breaking the problem into smaller chunks. IPDM does this where appropriate.

6. There are many special cases that can be solved efficiently. For example, to find the nearest neighbor for one dimensional data is a simple thing, costing no more than a sort. One does not need to compute all distances if only the closest point is of interest. (There are several other special cases that can be sped up, perhaps using k-d trees, or other algorithms. If interest is seen I’ll try to provide them.)

 

About these ads

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

生活在西班牙

自己动手丰衣足食

BlueAsteroid

Just another WordPress.com site

Jing's Blog

Just another WordPress.com site

Start from here......

我的心情魔方

天才遠私廚

希望能做一個分享各種資訊的好地方

语义噪声

西瓜大丸子汤的博客

Augmented Reality Blog

An augmented point of view

笑对人生,傲立寰宇

Just another WordPress.com site

Where On Earth Is Waldo?

A Project By Melanie Coles

the Serious Computer Vision Blog

A blog about computer vision and serious stuff

Cauthy's Blog

paper review...

Cornell Computer Vision Seminar Blog

Blog for CS 7670 - Special Topics in Computer Vision

datarazzi

Life through nerd-colored glasses

Luciana Haill

Augmenting Consciousness with EEG

槑烎

1,2,∞

Paul Tennent

Wanderings in the Blogosphere

turn off the lights, please

A bunch of random, thinned and stateless thoughts around the Web

Follow

Get every new post delivered to your Inbox.

%d bloggers like this: