root / trunk / web / dojo / dojox / math / stats.js @ 9
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/*
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Copyright (c) 2004-2010, The Dojo Foundation All Rights Reserved.
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Available via Academic Free License >= 2.1 OR the modified BSD license.
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see: http://dojotoolkit.org/license for details
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*/
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if(!dojo._hasResource["dojox.math.stats"]){ |
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dojo._hasResource["dojox.math.stats"]=true; |
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dojo.provide("dojox.math.stats");
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(function(){
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var st=dojox.math.stats;
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dojo.mixin(st,{sd:function(a){
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return Math.sqrt(st.variance(a));
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},variance:function(a){ |
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var _1=0,_2=0; |
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dojo.forEach(a,function(_3){
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_1+=_3; |
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_2+=Math.pow(_3,2);
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}); |
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return (_2/a.length)-Math.pow(_1/a.length,2); |
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},bestFit:function(a,_4,_5){ |
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_4=_4||"x",_5=_5||"y"; |
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if(a[0]!==undefined&&typeof (a[0])=="number"){ |
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a=dojo.map(a,function(_6,_7){
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return {x:_7,y:_6}; |
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}); |
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} |
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var sx=0,sy=0,_8=0,_9=0,_a=0,_b=0,_c=0,n=a.length,t; |
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for(var i=0;i<n;i++){ |
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sx+=a[i][_4]; |
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sy+=a[i][_5]; |
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_8+=Math.pow(a[i][_4],2);
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_9+=Math.pow(a[i][_5],2);
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_a+=a[i][_4]*a[i][_5]; |
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} |
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for(i=0;i<n;i++){ |
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t=a[i][_4]-sx/n; |
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_b+=t*t; |
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_c+=t*a[i][_5]; |
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} |
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var _d=_c/(_b||1); |
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var d=Math.sqrt((_8-Math.pow(sx,2)/n)*(_9-Math.pow(sy,2)/n)); |
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if(d===0){ |
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throw new Error("dojox.math.stats.bestFit: the denominator for Pearson's R is 0."); |
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} |
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var r=(_a-(sx*sy/n))/d;
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var r2=Math.pow(r,2); |
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if(_d<0){ |
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r=-r; |
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} |
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return {slope:_d,intercept:(sy-sx*_d)/(n||1),r:r,r2:r2}; |
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},forecast:function(a,x,_e,_f){ |
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var fit=st.bestFit(a,_e,_f);
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return (fit.slope*x)+fit.intercept;
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},mean:function(a){ |
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var t=0; |
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dojo.forEach(a,function(v){
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t+=v; |
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}); |
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return t/Math.max(a.length,1); |
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},min:function(a){ |
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return Math.min.apply(null,a); |
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},max:function(a){ |
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return Math.max.apply(null,a); |
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},median:function(a){ |
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var t=a.slice(0).sort(function(a,b){ |
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return a-b;
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}); |
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return (t[Math.floor(a.length/2)]+t[Math.ceil(a.length/2)])/2; |
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},mode:function(a){ |
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var o={},r=0,m=Number.MIN_VALUE; |
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dojo.forEach(a,function(v){
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(o[v]!==undefined)?o[v]++:o[v]=1; |
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}); |
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for(var p in o){ |
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if(m<o[p]){
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m=o[p],r=p; |
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} |
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} |
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return r;
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},sum:function(a){ |
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var sum=0; |
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dojo.forEach(a,function(n){
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sum+=n; |
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}); |
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return sum;
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},approxLin:function(a,pos){ |
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var p=pos*(a.length-1),t=Math.ceil(p),f=t-1; |
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if(f<0){ |
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return a[0]; |
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} |
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if(t>=a.length){
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return a[a.length-1]; |
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} |
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return a[f]*(t-p)+a[t]*(p-f);
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},summary:function(a,_10){ |
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if(!_10){
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a=a.slice(0);
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a.sort(function(a,b){
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return a-b;
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}); |
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} |
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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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return _11;
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}}); |
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})(); |
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} |