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[dygraphs.git] / tests / linear-regression-addseries.html
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54425b14 1<!DOCTYPE html>
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2<html>
3 <head>
10494b48 4 <meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7; IE=EmulateIE9">
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5 <title>Linear Regression</title>
6 <!--[if IE]>
a2b2c3a1 7 <script type="text/javascript" src="../excanvas.js"></script>
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8 <![endif]-->
9 <script type="text/javascript" src="../strftime/strftime-min.js"></script>
10 <script type="text/javascript" src="../rgbcolor/rgbcolor.js"></script>
11 <script type="text/javascript" src="../dygraph-canvas.js"></script>
12 <script type="text/javascript" src="../dygraph.js"></script>
13 <style type="text/css">
14 body { max-width: 640 px; }
15 </style>
16 </head>
17 <body>
18 <h2>Linear Regression Demo</h2>
19 <p>Click the buttons to generate linear regressions over either data
20 series. If you zoom in and click the regression button, the regression will
21 only be run over visible points. Zoom back out to see what the local
22 regression looks like over the full data.</p>
23
24 <div id="demodiv" style="width: 480px; height: 320px;"></div>
25
26 <script type="text/javascript">
27 var data = [];
28 for (var i = 0; i < 120; i++) {
29 data.push([i,
30 i / 5.0 + 10.0 * Math.sin(i / 3.0),
31 30.0 - i / 5.0 - 10.0 * Math.sin(i / 3.0 + 1.0)]);
32 }
33 var labels = ['X', 'Y1', 'Y2'];
34 var orig_colors = [];
35
36 g = new Dygraph(
37 document.getElementById("demodiv"),
38 data,
39 {
40 labels: labels,
41 drawPoints: true,
de0445fc 42 strokeWidth: 0.0,
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43 drawCallback: function(g, is_initial) {
44 if (!is_initial) return;
45 var c = g.getColors();
46 for (var i = 0; i < c.length; i++) orig_colors.push(c[i]);
47 }
48 }
49 );
50
51 // coefficients of regression for each series.
52 // if coeffs = [ null, [1, 2], null ] then we draw a regression for series 1
53 // only. The regression line is y = 1 + 2 * x.
54 var coeffs = [ null, null, null ];
55 function regression(series) {
56 // Only run the regression over visible points.
57 var range = g.xAxisRange();
58
59 var sum_xy = 0.0, sum_x = 0.0, sum_y = 0.0, sum_x2 = 0.0, num = 0;
60 for (var i = 0; i < data.length; i++) {
61 var x = data[i][0];
62 if (x < range[0] || x > range[1]) continue;
63
64 var y = data[i][series];
65 if (y == null) continue;
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66 if (y.length == 2) {
67 // using fractions
68 y = y[0] / y[1];
69 }
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70
71 num++;
72 sum_x += x;
73 sum_y += y;
74 sum_xy += x * y;
75 sum_x2 += x * x;
76 }
77
78 var a = (sum_xy - sum_x * sum_y / num) / (sum_x2 - sum_x * sum_x / num);
79 var b = (sum_y - a * sum_x) / num;
80
81 coeffs[series] = [b, a];
4df1af70 82 if (typeof(console) != 'undefined') {
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83 console.log("coeffs(" + series + "): [" + b + ", " + a + "]");
84 }
85
86 updateChart();
87 }
88
89 function updateChart() {
90 // Generate a new data set with the regression lines.
91 var new_labels = [];
92 var new_colors = [];
de0445fc 93 var new_opts = {};
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94 for (var i = 0; i < labels.length; i++) {
95 new_labels.push(labels[i]);
96 if (i) new_colors.push(orig_colors[i - 1]);
97 if (coeffs[i]) {
98 // Darken the series by 50% to generate its regression.
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99 var label = labels[i] + " Regression";
100 new_labels.push(label);
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101 var c = new RGBColor(orig_colors[i - 1]);
102 c.r = Math.floor(255 - 0.5 * (255 - c.r));
103 c.g = Math.floor(255 - 0.5 * (255 - c.g));
104 c.b = Math.floor(255 - 0.5 * (255 - c.b));
105 new_colors.push(c.toHex());
227b93cc 106 new_opts[label] = {
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107 drawPoints: false,
108 strokeWidth: 1.0
109 };
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110 }
111 }
112
113 var new_data = [];
114 for (var i = 0; i < data.length; i++) {
115 new_data.push([]);
116 for (var j = 0; j < data[i].length; j++) {
117 new_data[i].push(data[i][j]);
118 if (coeffs[j]) {
119 new_data[i].push(coeffs[j][0] + coeffs[j][1] * data[i][0]);
120 }
121 }
122 }
123
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124 new_opts.file = new_data;
125 new_opts.labels = new_labels;
126 new_opts.colors = new_colors;
127 g.updateOptions(new_opts);
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128 }
129
130 function clearLines() {
131 for (var i = 0; i < coeffs.length; i++) coeffs[i] = null;
132 updateChart();
133 }
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134
135 </script>
136
137 <div style="position: absolute; left: 500px; top: 150px;">
138 <input type=button style="color: green;" value="Regression (Y1)" onClick="regression(1)" />
139 <br/><br/>
140 <input type=button style="color: blue;" value="Regression (Y2)" onClick="regression(2)" />
141 <br/><br/>
142 <input type=button value="Clear Lines" onClick="clearLines()" />
143 </div>
144</body>
145</html>