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ndarray-distance v1.0.0

Lp distance between ndarrays

ndarray-distance

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

build status

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

Metadata

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