ndarray-distance

Computes the Lp distance between two ndarrays. Works both in node.js and in browserify.

Example

var distance = require("ndarray-distance")
var ndarray = require("ndarray")
 
//Create two arrays
var a = ndarray([1, 2, 3, 4, 5])
var b = ndarray([0, 2, 3, 10, 6])
 
 
//First compute sum of squared distances
var l2Dist = distance(a, b)
 
//Can also compute l1 distance (absolute difference)
var l1Dist = distance(a, b, 1)
 
//And maximum distance
var linfDist = distance(a, b, Infinity)
 
//And any other Lp distance as well
var l3Dist = distance(a, b, 3)

Install

Install using npm:

npm install ndarray-distance

API

require("ndarray-distance")(a, b[, p])

Computes the Lp distance between two ndarrays a and b. That is,

dist(a,b,p) = ( sum |a[i] - b[i]|^p )^(1/p)

Note that here a and b do not have to be vectors and can be images or volumes.

• a and b are both ndarrays with the same shape
• p is a parameter that determines the exponent of the metric. The default value is p=2

Special values of p include:

• p=0 which counts the number of entries where a and b differ
• p=1 which is the absolute difference between a and b
• p=2 which is the ordinary Euclidean sum of squared differences
• p=Infinity which is the maximum absolute difference between a and b

Returns The Lp distance between a and b

License

(c) 2014 Mikola Lysenko. MIT License