root / trunk / web / dojo / dojox / math / stats.js @ 11
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| 1 | 9 | andrej.cim | /*
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| 2 | Copyright (c) 2004-2010, The Dojo Foundation All Rights Reserved.
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| 3 | Available via Academic Free License >= 2.1 OR the modified BSD license.
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| 4 | see: http://dojotoolkit.org/license for details
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| 5 | */
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| 6 | |||
| 7 | |||
| 8 | if(!dojo._hasResource["dojox.math.stats"]){ |
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| 9 | dojo._hasResource["dojox.math.stats"]=true; |
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| 10 | dojo.provide("dojox.math.stats");
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| 11 | (function(){
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| 12 | var st=dojox.math.stats;
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| 13 | dojo.mixin(st,{sd:function(a){
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| 14 | return Math.sqrt(st.variance(a));
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| 15 | },variance:function(a){ |
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| 16 | var _1=0,_2=0; |
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| 17 | dojo.forEach(a,function(_3){
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| 18 | _1+=_3; |
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| 19 | _2+=Math.pow(_3,2);
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| 20 | }); |
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| 21 | return (_2/a.length)-Math.pow(_1/a.length,2); |
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| 22 | },bestFit:function(a,_4,_5){ |
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| 23 | _4=_4||"x",_5=_5||"y"; |
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| 24 | if(a[0]!==undefined&&typeof (a[0])=="number"){ |
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| 25 | a=dojo.map(a,function(_6,_7){
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| 26 | return {x:_7,y:_6}; |
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| 27 | }); |
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| 28 | } |
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| 29 | var sx=0,sy=0,_8=0,_9=0,_a=0,_b=0,_c=0,n=a.length,t; |
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| 30 | for(var i=0;i<n;i++){ |
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| 31 | sx+=a[i][_4]; |
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| 32 | sy+=a[i][_5]; |
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| 33 | _8+=Math.pow(a[i][_4],2);
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| 34 | _9+=Math.pow(a[i][_5],2);
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| 35 | _a+=a[i][_4]*a[i][_5]; |
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| 36 | } |
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| 37 | for(i=0;i<n;i++){ |
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| 38 | t=a[i][_4]-sx/n; |
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| 39 | _b+=t*t; |
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| 40 | _c+=t*a[i][_5]; |
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| 41 | } |
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| 42 | var _d=_c/(_b||1); |
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| 43 | var d=Math.sqrt((_8-Math.pow(sx,2)/n)*(_9-Math.pow(sy,2)/n)); |
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| 44 | if(d===0){ |
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| 45 | throw new Error("dojox.math.stats.bestFit: the denominator for Pearson's R is 0."); |
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| 46 | } |
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| 47 | var r=(_a-(sx*sy/n))/d;
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| 48 | var r2=Math.pow(r,2); |
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| 49 | if(_d<0){ |
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| 50 | r=-r; |
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| 51 | } |
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| 52 | return {slope:_d,intercept:(sy-sx*_d)/(n||1),r:r,r2:r2}; |
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| 53 | },forecast:function(a,x,_e,_f){ |
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| 54 | var fit=st.bestFit(a,_e,_f);
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| 55 | return (fit.slope*x)+fit.intercept;
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| 56 | },mean:function(a){ |
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| 57 | var t=0; |
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| 58 | dojo.forEach(a,function(v){
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| 59 | t+=v; |
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| 60 | }); |
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| 61 | return t/Math.max(a.length,1); |
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| 62 | },min:function(a){ |
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| 63 | return Math.min.apply(null,a); |
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| 64 | },max:function(a){ |
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| 65 | return Math.max.apply(null,a); |
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| 66 | },median:function(a){ |
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| 67 | var t=a.slice(0).sort(function(a,b){ |
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| 68 | return a-b;
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| 69 | }); |
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| 70 | return (t[Math.floor(a.length/2)]+t[Math.ceil(a.length/2)])/2; |
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| 71 | },mode:function(a){ |
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| 72 | var o={},r=0,m=Number.MIN_VALUE; |
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| 73 | dojo.forEach(a,function(v){
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| 74 | (o[v]!==undefined)?o[v]++:o[v]=1; |
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| 75 | }); |
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| 76 | for(var p in o){ |
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| 77 | if(m<o[p]){
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| 78 | m=o[p],r=p; |
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| 79 | } |
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| 80 | } |
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| 81 | return r;
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| 82 | },sum:function(a){ |
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| 83 | var sum=0; |
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| 84 | dojo.forEach(a,function(n){
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| 85 | sum+=n; |
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| 86 | }); |
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| 87 | return sum;
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| 88 | },approxLin:function(a,pos){ |
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| 89 | var p=pos*(a.length-1),t=Math.ceil(p),f=t-1; |
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| 90 | if(f<0){ |
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| 91 | return a[0]; |
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| 92 | } |
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| 93 | if(t>=a.length){
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| 94 | return a[a.length-1]; |
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| 95 | } |
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| 96 | return a[f]*(t-p)+a[t]*(p-f);
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| 97 | },summary:function(a,_10){ |
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| 98 | if(!_10){
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| 99 | a=a.slice(0);
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| 100 | a.sort(function(a,b){
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| 101 | return a-b;
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| 102 | }); |
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| 103 | } |
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| 104 | var l=st.approxLin,_11={min:a[0],p25:l(a,0.25),med:l(a,0.5),p75:l(a,0.75),max:a[a.length-1],p10:l(a,0.1),p90:l(a,0.9)}; |
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| 105 | return _11;
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| 106 | }}); |
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| 107 | })(); |
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| 108 | } |