// lib/extramath.js // https://github.com/gnh1201/welsonjs function DTM() { this.data = []; this.terms = []; this.add = function(s) { var w = s.trim().split(/\s+/); for (var i = 0; i < w.length; i++) { if (this.terms.indexOf(w[i]) < 0) this.terms.push(w[i]); } this.data.push(w); }; this.toArray = function() { var dtm = []; for (var i = 0; i < this.data.length; i++) { var dt = []; for (var k = 0; k < this.terms.length; k++) { dt.push(this.data[i].indexOf(this.terms[k]) < 0 ? 0 : 1); } dtm.push(dt); } return dtm; }; } function cos(A, B) { var dotproduct = 0; var mA = 0; var mB = 0; for (i = 0; i < A.length; i++) { dotproduct += (A[i] * B[i]); mA += (A[i] * A[i]); mB += (B[i] * B[i]); } mA = Math.sqrt(mA); mB = Math.sqrt(mB); var similarity = (dotproduct) / ((mA) * (mB)) return similarity; } exports.DTM = DTM; exports.cos = cos; exports.measureSimilarity = function(s1, s2) { var dtm = new DTM(); dtm.add(s1); dtm.add(s2); var mat = dtm.toArray(); return cos(mat[0], mat[1]); }; exports.VERSIONINFO = "ExtraMath module (extramath.js) version 0.0.3"; exports.AUTHOR = "catswords@protonmail.com"; exports.global = global; exports.require = global.require;