[dygraphs.git] / tests / linear-regression-fractions.html

<!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]-->
    <script type="text/javascript" src="../strftime/strftime-min.js"></script>
    <script type="text/javascript" src="../rgbcolor/rgbcolor.js"></script>
    <script type="text/javascript" src="../dygraph-canvas.js"></script>
    <script type="text/javascript" src="../dygraph.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 = "X,Y1,Y2\n";
      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)]);
        data += i + "," + i + "/120," + (i*(120-i)) + "/" + (60*60) + "\n";
      }

      g = new Dygraph(
              document.getElementById("demodiv"),
              data,
              {
                underlayCallback: drawLines,
                drawPoints: true,
                strokeWidth: 0.0,
                fractions: true,
                errorBars: true
              }
          );

      // 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 < g.numRows(); i++) {
          var x = g.getValue(i, 0);
          if (x < range[0] || x > range[1]) continue;

          var y = g.getValue(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 + "]");
        }

        g.updateOptions({});  // forces a redraw.
      }

      function clearLines() {
        for (var i = 0; i < coeffs.length; i++) coeffs[i] = null;
        g.updateOptions({});
      }

      function drawLines(ctx, area, layout) {
        if (typeof(g) == 'undefined') return;  // won't be set on the initial draw.

        var range = g.xAxisRange();
        for (var i = 0; i < coeffs.length; i++) {
          if (!coeffs[i]) continue;
          var a = coeffs[i][1];
          var b = coeffs[i][0];

          var x1 = range[0];
          var y1 = a * x1 + b;
          var x2 = range[1];
          var y2 = a * x2 + b;

          // Scale up to percentages, rather than fractions.
          y1 *= 100;
          y2 *= 100;

          var p1 = g.toDomCoords(x1, y1);
          var p2 = g.toDomCoords(x2, y2);

          var c = new RGBColor(g.getColors()[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));
          var color = c.toHex();
          ctx.save();
          ctx.strokeStyle = color;
          ctx.lineWidth = 1.0;
          ctx.beginPath();
          ctx.moveTo(p1[0], p1[1]);
          ctx.lineTo(p2[0], p2[1]);
          ctx.closePath();
          ctx.stroke();
          ctx.restore();
        }
      }
      
    </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>
Commit	Line	Data
54425b14	1	<!DOCTYPE html>
d1dfab80 DV	2	<html>
d1dfab80 DV	3	<head>
10494b48	4	<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7; IE=EmulateIE9">
d1dfab80 DV	5	<title>Linear Regression</title>
	6	<!--[if IE]>
	7	<script type="text/javascript" src="../excanvas.js"></script>
	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 = "X,Y1,Y2\n";
	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	data += i + "," + i + "/120," + (i(120-i)) + "/" + (6060) + "\n";
	33	}
	34
	35	g = new Dygraph(
	36	document.getElementById("demodiv"),
	37	data,
	38	{
	39	underlayCallback: drawLines,
	40	drawPoints: true,
	41	strokeWidth: 0.0,
	42	fractions: true,
	43	errorBars: true
	44	}
	45	);
	46
	47	// coefficients of regression for each series.
	48	// if coeffs = [ null, [1, 2], null ] then we draw a regression for series 1
	49	// only. The regression line is y = 1 + 2 * x.
	50	var coeffs = [ null, null, null ];
	51	function regression(series) {
	52	// Only run the regression over visible points.
	53	var range = g.xAxisRange();
	54
	55	var sum_xy = 0.0, sum_x = 0.0, sum_y = 0.0, sum_x2 = 0.0, num = 0;
	56	for (var i = 0; i < g.numRows(); i++) {
	57	var x = g.getValue(i, 0);
	58	if (x < range[0] \|\| x > range[1]) continue;
	59
	60	var y = g.getValue(i, series);
	61	if (y == null) continue;
	62	if (y.length == 2) {
	63	// using fractions
	64	y = y[0] / y[1];
	65	}
	66
	67	num++;
	68	sum_x += x;
69	sum_y += y;
70	sum_xy += x * y;
71	sum_x2 += x * x;
72	}
73
74	var a = (sum_xy - sum_x * sum_y / num) / (sum_x2 - sum_x * sum_x / num);
75	var b = (sum_y - a * sum_x) / num;
76
77	coeffs[series] = [b, a];
78	if (typeof(console) != 'undefined') {
79	console.log("coeffs(" + series + "): [" + b + ", " + a + "]");
80	}
81
82	g.updateOptions({}); // forces a redraw.
83	}
84
85	function clearLines() {
86	for (var i = 0; i < coeffs.length; i++) coeffs[i] = null;
87	g.updateOptions({});
88	}
89
90	function drawLines(ctx, area, layout) {
91	if (typeof(g) == 'undefined') return; // won't be set on the initial draw.
92
93	var range = g.xAxisRange();
94	for (var i = 0; i < coeffs.length; i++) {
95	if (!coeffs[i]) continue;
96	var a = coeffs[i][1];
97	var b = coeffs[i][0];
98
99	var x1 = range[0];
100	var y1 = a * x1 + b;
101	var x2 = range[1];
102	var y2 = a * x2 + b;
103
104	// Scale up to percentages, rather than fractions.
105	y1 *= 100;
106	y2 *= 100;
107
108	var p1 = g.toDomCoords(x1, y1);
109	var p2 = g.toDomCoords(x2, y2);
110
111	var c = new RGBColor(g.getColors()[i - 1]);
112	c.r = Math.floor(255 - 0.5 * (255 - c.r));
113	c.g = Math.floor(255 - 0.5 * (255 - c.g));
114	c.b = Math.floor(255 - 0.5 * (255 - c.b));
115	var color = c.toHex();
116	ctx.save();
117	ctx.strokeStyle = color;
118	ctx.lineWidth = 1.0;
119	ctx.beginPath();
120	ctx.moveTo(p1[0], p1[1]);
121	ctx.lineTo(p2[0], p2[1]);
122	ctx.closePath();
123	ctx.stroke();
124	ctx.restore();
125	}
126	}
127
128	</script>
129
130	<div style="position: absolute; left: 500px; top: 150px;">
131	<input type=button style="color: green;" value="Regression (Y1)" onClick="regression(1)" />
132	<br/><br/>
133	<input type=button style="color: blue;" value="Regression (Y2)" onClick="regression(2)" />
134	<br/><br/>
135	<input type=button value="Clear Lines" onClick="clearLines()" />
136	</div>
137	</body>
138	</html>