forked from danvk/dygraphs
-
Notifications
You must be signed in to change notification settings - Fork 0
/
linear-regression-addseries.html
147 lines (130 loc) · 4.71 KB
/
linear-regression-addseries.html
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7; IE=EmulateIE9">
<title>Linear Regression</title>
<!--[if IE]>
<script type="text/javascript" src="../excanvas.js"></script>
<![endif]-->
<!--
For production (minified) code, use:
<script type="text/javascript" src="dygraph-combined.js"></script>
-->
<script type="text/javascript" src="../dygraph-dev.js"></script>
<style type="text/css">
body { max-width: 640 px; }
</style>
</head>
<body>
<h2>Linear Regression Demo</h2>
<p>Click the buttons to generate linear regressions over either data
series. If you zoom in and click the regression button, the regression will
only be run over visible points. Zoom back out to see what the local
regression looks like over the full data.</p>
<div id="demodiv" style="width: 480px; height: 320px;"></div>
<script type="text/javascript">
var data = [];
for (var i = 0; i < 120; i++) {
data.push([i,
i / 5.0 + 10.0 * Math.sin(i / 3.0),
30.0 - i / 5.0 - 10.0 * Math.sin(i / 3.0 + 1.0)]);
}
var labels = ['X', 'Y1', 'Y2'];
var orig_colors = [];
g = new Dygraph(
document.getElementById("demodiv"),
data,
{
labels: labels,
drawPoints: true,
strokeWidth: 0.0,
drawCallback: function(g, is_initial) {
if (!is_initial) return;
var c = g.getColors();
for (var i = 0; i < c.length; i++) orig_colors.push(c[i]);
}
}
);
// coefficients of regression for each series.
// if coeffs = [ null, [1, 2], null ] then we draw a regression for series 1
// only. The regression line is y = 1 + 2 * x.
var coeffs = [ null, null, null ];
function regression(series) {
// Only run the regression over visible points.
var range = g.xAxisRange();
var sum_xy = 0.0, sum_x = 0.0, sum_y = 0.0, sum_x2 = 0.0, num = 0;
for (var i = 0; i < data.length; i++) {
var x = data[i][0];
if (x < range[0] || x > range[1]) continue;
var y = data[i][series];
if (y == null) continue;
if (y.length == 2) {
// using fractions
y = y[0] / y[1];
}
num++;
sum_x += x;
sum_y += y;
sum_xy += x * y;
sum_x2 += x * x;
}
var a = (sum_xy - sum_x * sum_y / num) / (sum_x2 - sum_x * sum_x / num);
var b = (sum_y - a * sum_x) / num;
coeffs[series] = [b, a];
if (typeof(console) != 'undefined') {
console.log("coeffs(" + series + "): [" + b + ", " + a + "]");
}
updateChart();
}
function updateChart() {
// Generate a new data set with the regression lines.
var new_labels = [];
var new_colors = [];
var new_opts = {};
for (var i = 0; i < labels.length; i++) {
new_labels.push(labels[i]);
if (i) new_colors.push(orig_colors[i - 1]);
if (coeffs[i]) {
// Darken the series by 50% to generate its regression.
var label = labels[i] + " Regression";
new_labels.push(label);
var c = new RGBColorParser(orig_colors[i - 1]);
c.r = Math.floor(255 - 0.5 * (255 - c.r));
c.g = Math.floor(255 - 0.5 * (255 - c.g));
c.b = Math.floor(255 - 0.5 * (255 - c.b));
new_colors.push(c.toHex());
new_opts[label] = {
drawPoints: false,
strokeWidth: 1.0
};
}
}
var new_data = [];
for (var i = 0; i < data.length; i++) {
new_data.push([]);
for (var j = 0; j < data[i].length; j++) {
new_data[i].push(data[i][j]);
if (coeffs[j]) {
new_data[i].push(coeffs[j][0] + coeffs[j][1] * data[i][0]);
}
}
}
new_opts.file = new_data;
new_opts.labels = new_labels;
new_opts.colors = new_colors;
g.updateOptions(new_opts);
}
function clearLines() {
for (var i = 0; i < coeffs.length; i++) coeffs[i] = null;
updateChart();
}
</script>
<div style="position: absolute; left: 500px; top: 150px;">
<input type=button style="color: green;" value="Regression (Y1)" onClick="regression(1)" />
<br/><br/>
<input type=button style="color: blue;" value="Regression (Y2)" onClick="regression(2)" />
<br/><br/>
<input type=button value="Clear Lines" onClick="clearLines()" />
</div>
</body>
</html>