[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]-->
    <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 = [];
      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 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>
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 DV	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">
176c94a4	27	var data = [];
05a1d116	28	for (var i = 0; i < 120; i++) {
176c94a4 DV	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)]);
05a1d116 DV	32	}
	33
	34	g = new Dygraph(
	35	document.getElementById("demodiv"),
	36	data,
	37	{
176c94a4	38	labels: ['X', 'Y1', 'Y2'],
05a1d116	39	underlayCallback: drawLines,
de0445fc	40	drawPoints: true,
176c94a4	41	strokeWidth: 0.0
05a1d116 DV	42	}
	43	);
	44
	45	// coefficients of regression for each series.
	46	// if coeffs = [ null, [1, 2], null ] then we draw a regression for series 1
	47	// only. The regression line is y = 1 + 2 * x.
	48	var coeffs = [ null, null, null ];
	49	function regression(series) {
	50	// Only run the regression over visible points.
	51	var range = g.xAxisRange();
	52
	53	var sum_xy = 0.0, sum_x = 0.0, sum_y = 0.0, sum_x2 = 0.0, num = 0;
	54	for (var i = 0; i < g.numRows(); i++) {
	55	var x = g.getValue(i, 0);
	56	if (x < range[0] \|\| x > range[1]) continue;
	57
	58	var y = g.getValue(i, series);
	59	if (y == null) continue;
c5a37449 DV	60	if (y.length == 2) {
	61	// using fractions
	62	y = y[0] / y[1];
	63	}
05a1d116 DV	64
	65	num++;
	66	sum_x += x;
	67	sum_y += y;
	68	sum_xy += x * y;
	69	sum_x2 += x * x;
	70	}
	71
	72	var a = (sum_xy - sum_x * sum_y / num) / (sum_x2 - sum_x * sum_x / num);
	73	var b = (sum_y - a * sum_x) / num;
	74
	75	coeffs[series] = [b, a];
4df1af70	76	if (typeof(console) != 'undefined') {
2a07b0ad DV	77	console.log("coeffs(" + series + "): [" + b + ", " + a + "]");
2a07b0ad DV	78	}
05a1d116 DV	79
	80	g.updateOptions({}); // forces a redraw.
	81	}
	82
	83	function clearLines() {
	84	for (var i = 0; i < coeffs.length; i++) coeffs[i] = null;
	85	g.updateOptions({});
	86	}
	87
	88	function drawLines(ctx, area, layout) {
	89	if (typeof(g) == 'undefined') return; // won't be set on the initial draw.
	90
	91	var range = g.xAxisRange();
	92	for (var i = 0; i < coeffs.length; i++) {
	93	if (!coeffs[i]) continue;
	94	var a = coeffs[i][1];
	95	var b = coeffs[i][0];
	96
	97	var x1 = range[0];
	98	var y1 = a * x1 + b;
	99	var x2 = range[1];
	100	var y2 = a * x2 + b;
	101
	102	var p1 = g.toDomCoords(x1, y1);
	103	var p2 = g.toDomCoords(x2, y2);
	104
34bbe78b DV	105	var c = new RGBColor(g.getColors()[i - 1]);
	106	c.r = Math.floor(255 - 0.5 * (255 - c.r));
	107	c.g = Math.floor(255 - 0.5 * (255 - c.g));
	108	c.b = Math.floor(255 - 0.5 * (255 - c.b));
	109	var color = c.toHex();
05a1d116 DV	110	ctx.save();
	111	ctx.strokeStyle = color;
	112	ctx.lineWidth = 1.0;
	113	ctx.beginPath();
	114	ctx.moveTo(p1[0], p1[1]);
	115	ctx.lineTo(p2[0], p2[1]);
	116	ctx.closePath();
	117	ctx.stroke();
	118	ctx.restore();
	119	}
	120	}
	121
	122	</script>
	123
	124	<div style="position: absolute; left: 500px; top: 150px;">
	125	<input type=button style="color: green;" value="Regression (Y1)" onClick="regression(1)" />
	126	<br/><br/>
	127	<input type=button style="color: blue;" value="Regression (Y2)" onClick="regression(2)" />
	128	<br/><br/>
	129	<input type=button value="Clear Lines" onClick="clearLines()" />
	130	</div>
	131	</body>
	132	</html>