website/themes/hugo-theme-wave/static/bower_components/lunr.js/lib/vector.js
2020-01-12 23:32:32 +01:00

132 lines
2.8 KiB
JavaScript

/*!
* lunr.Vector
* Copyright (C) @YEAR Oliver Nightingale
*/
/**
* lunr.Vectors implement vector related operations for
* a series of elements.
*
* @constructor
*/
lunr.Vector = function () {
this._magnitude = null
this.list = undefined
this.length = 0
}
/**
* lunr.Vector.Node is a simple struct for each node
* in a lunr.Vector.
*
* @private
* @param {Number} The index of the node in the vector.
* @param {Object} The data at this node in the vector.
* @param {lunr.Vector.Node} The node directly after this node in the vector.
* @constructor
* @memberOf Vector
*/
lunr.Vector.Node = function (idx, val, next) {
this.idx = idx
this.val = val
this.next = next
}
/**
* Inserts a new value at a position in a vector.
*
* @param {Number} The index at which to insert a value.
* @param {Object} The object to insert in the vector.
* @memberOf Vector.
*/
lunr.Vector.prototype.insert = function (idx, val) {
this._magnitude = undefined;
var list = this.list
if (!list) {
this.list = new lunr.Vector.Node (idx, val, list)
return this.length++
}
if (idx < list.idx) {
this.list = new lunr.Vector.Node (idx, val, list)
return this.length++
}
var prev = list,
next = list.next
while (next != undefined) {
if (idx < next.idx) {
prev.next = new lunr.Vector.Node (idx, val, next)
return this.length++
}
prev = next, next = next.next
}
prev.next = new lunr.Vector.Node (idx, val, next)
return this.length++
}
/**
* Calculates the magnitude of this vector.
*
* @returns {Number}
* @memberOf Vector
*/
lunr.Vector.prototype.magnitude = function () {
if (this._magnitude) return this._magnitude
var node = this.list,
sumOfSquares = 0,
val
while (node) {
val = node.val
sumOfSquares += val * val
node = node.next
}
return this._magnitude = Math.sqrt(sumOfSquares)
}
/**
* Calculates the dot product of this vector and another vector.
*
* @param {lunr.Vector} otherVector The vector to compute the dot product with.
* @returns {Number}
* @memberOf Vector
*/
lunr.Vector.prototype.dot = function (otherVector) {
var node = this.list,
otherNode = otherVector.list,
dotProduct = 0
while (node && otherNode) {
if (node.idx < otherNode.idx) {
node = node.next
} else if (node.idx > otherNode.idx) {
otherNode = otherNode.next
} else {
dotProduct += node.val * otherNode.val
node = node.next
otherNode = otherNode.next
}
}
return dotProduct
}
/**
* Calculates the cosine similarity between this vector and another
* vector.
*
* @param {lunr.Vector} otherVector The other vector to calculate the
* similarity with.
* @returns {Number}
* @memberOf Vector
*/
lunr.Vector.prototype.similarity = function (otherVector) {
return this.dot(otherVector) / (this.magnitude() * otherVector.magnitude())
}