| <!DOCTYPE html> |
| <!-- |
| Copyright (c) 2014 The Chromium Authors. All rights reserved. |
| Use of this source code is governed by a BSD-style license that can be |
| found in the LICENSE file. |
| --> |
| <link rel="import" href="/base/range.html"> |
| <script> |
| 'use strict'; |
| |
| tr.exportTo('tr.b', function() { |
| |
| function identity(d) { |
| return d; |
| } |
| |
| function Statistics() { |
| } |
| |
| Statistics.sum = function(ary, opt_func, opt_this) { |
| var func = opt_func || identity; |
| var ret = 0; |
| for (var i = 0; i < ary.length; i++) |
| ret += func.call(opt_this, ary[i], i); |
| return ret; |
| }; |
| |
| Statistics.mean = function(ary, opt_func, opt_this) { |
| return Statistics.sum(ary, opt_func, opt_this) / ary.length; |
| }; |
| |
| Statistics.variance = function(ary, opt_func, opt_this) { |
| var func = opt_func || identity; |
| var mean = Statistics.mean(ary, func, opt_this); |
| var sumOfSquaredDistances = Statistics.sum( |
| ary, |
| function(d, i) { |
| var v = func.call(this, d, i) - mean; |
| return v * v; |
| }, |
| opt_this); |
| return sumOfSquaredDistances / (ary.length - 1); |
| }; |
| |
| Statistics.stddev = function(ary, opt_func, opt_this) { |
| return Math.sqrt( |
| Statistics.variance(ary, opt_func, opt_this)); |
| }; |
| |
| Statistics.max = function(ary, opt_func, opt_this) { |
| var func = opt_func || identity; |
| var ret = -Infinity; |
| for (var i = 0; i < ary.length; i++) |
| ret = Math.max(ret, func.call(opt_this, ary[i], i)); |
| return ret; |
| }; |
| |
| Statistics.min = function(ary, opt_func, opt_this) { |
| var func = opt_func || identity; |
| var ret = Infinity; |
| for (var i = 0; i < ary.length; i++) |
| ret = Math.min(ret, func.call(opt_this, ary[i], i)); |
| return ret; |
| }; |
| |
| Statistics.range = function(ary, opt_func, opt_this) { |
| var func = opt_func || identity; |
| var ret = new tr.b.Range(); |
| for (var i = 0; i < ary.length; i++) |
| ret.addValue(func.call(opt_this, ary[i], i)); |
| return ret; |
| } |
| |
| Statistics.percentile = function(ary, percent, opt_func, opt_this) { |
| if (!(percent >= 0 && percent <= 1)) |
| throw new Error('percent must be [0,1]'); |
| |
| var func = opt_func || identity; |
| var tmp = new Array(ary.length); |
| for (var i = 0; i < ary.length; i++) |
| tmp[i] = func.call(opt_this, ary[i], i); |
| tmp.sort(); |
| var idx = Math.floor((ary.length - 1) * percent); |
| return tmp[idx]; |
| }; |
| |
| return { |
| Statistics: Statistics |
| }; |
| }); |
| </script> |
