[dygraphs.git] / tests / linear-regression.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]-->
    <!--
    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)]);
      }

      g = new Dygraph(
              document.getElementById("demodiv"),
              data,
              {
                labels: ['X', 'Y1', 'Y2'],
                underlayCallback: drawLines,
                drawPoints: true,
                strokeWidth: 0.0
              }
          );

      // 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;

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

          var c = new RGBColorParser(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>
05a1d116 DV	2	<html>
05a1d116 DV	3	<head>
10494b48	4	<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7; IE=EmulateIE9">
05a1d116 DV	5	<title>Linear Regression</title>
05a1d116 DV	6	<!--[if IE]>
a2b2c3a1	7	<script type="text/javascript" src="../excanvas.js"></script>
05a1d116	8	<![endif]-->
7e5ddc94 DV	9	<!--
	10	For production (minified) code, use:
	11	<script type="text/javascript" src="dygraph-combined.js"></script>
	12	-->
	13	<script type="text/javascript" src="../dygraph-dev.js"></script>
	14
05a1d116 DV	15	<style type="text/css">
	16	body { max-width: 640 px; }
	17	</style>
	18	</head>
	19	<body>
	20	<h2>Linear Regression Demo</h2>
	21	<p>Click the buttons to generate linear regressions over either data
	22	series. If you zoom in and click the regression button, the regression will
	23	only be run over visible points. Zoom back out to see what the local
	24	regression looks like over the full data.</p>
	25
	26	<div id="demodiv" style="width: 480px; height: 320px;"></div>
	27
	28	<script type="text/javascript">
176c94a4	29	var data = [];
05a1d116	30	for (var i = 0; i < 120; i++) {
176c94a4 DV	31	data.push([i,
	32	i / 5.0 + 10.0 * Math.sin(i / 3.0),
	33	30.0 - i / 5.0 - 10.0 * Math.sin(i / 3.0 + 1.0)]);
05a1d116 DV	34	}
	35
	36	g = new Dygraph(
	37	document.getElementById("demodiv"),
	38	data,
	39	{
176c94a4	40	labels: ['X', 'Y1', 'Y2'],
05a1d116	41	underlayCallback: drawLines,
de0445fc	42	drawPoints: true,
176c94a4	43	strokeWidth: 0.0
05a1d116 DV	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;
c5a37449 DV	62	if (y.length == 2) {
	63	// using fractions
	64	y = y[0] / y[1];
	65	}
05a1d116 DV	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];
4df1af70	78	if (typeof(console) != 'undefined') {
2a07b0ad DV	79	console.log("coeffs(" + series + "): [" + b + ", " + a + "]");
2a07b0ad DV	80	}
05a1d116 DV	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	var p1 = g.toDomCoords(x1, y1);
	105	var p2 = g.toDomCoords(x2, y2);
	106
42142795	107	var c = new RGBColorParser(g.getColors()[i - 1]);
34bbe78b DV	108	c.r = Math.floor(255 - 0.5 * (255 - c.r));
	109	c.g = Math.floor(255 - 0.5 * (255 - c.g));
	110	c.b = Math.floor(255 - 0.5 * (255 - c.b));
	111	var color = c.toHex();
05a1d116 DV	112	ctx.save();
	113	ctx.strokeStyle = color;
	114	ctx.lineWidth = 1.0;
	115	ctx.beginPath();
	116	ctx.moveTo(p1[0], p1[1]);
	117	ctx.lineTo(p2[0], p2[1]);
	118	ctx.closePath();
	119	ctx.stroke();
	120	ctx.restore();
	121	}
	122	}
	123
	124	</script>
	125
	126	<div style="position: absolute; left: 500px; top: 150px;">
	127	<input type=button style="color: green;" value="Regression (Y1)" onClick="regression(1)" />
	128	<br/><br/>
	129	<input type=button style="color: blue;" value="Regression (Y2)" onClick="regression(2)" />
	130	<br/><br/>
	131	<input type=button value="Clear Lines" onClick="clearLines()" />
	132	</div>
	133	</body>
	134	</html>