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

<!DOCTYPE html>
<html>
  <head>
    <link rel="stylesheet" href="../dist/dygraph.css">
    <title>Linear Regression</title>
    <script type="text/javascript" src="../dist/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 toHex(rgb) {
        return 'rgb(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ')';
      }

      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 = Dygraph.toRGB_(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 = toHex(c);
          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>
fd6b8dad	4	<link rel="stylesheet" href="../dist/dygraph.css">
05a1d116	5	<title>Linear Regression</title>
fbd6834a	6	<script type="text/javascript" src="../dist/dygraph.js"></script>
7e5ddc94	7
05a1d116 DV	8	<style type="text/css">
	9	body { max-width: 640 px; }
	10	</style>
	11	</head>
	12	<body>
	13	<h2>Linear Regression Demo</h2>
	14	<p>Click the buttons to generate linear regressions over either data
	15	series. If you zoom in and click the regression button, the regression will
	16	only be run over visible points. Zoom back out to see what the local
	17	regression looks like over the full data.</p>
	18
	19	<div id="demodiv" style="width: 480px; height: 320px;"></div>
	20
	21	<script type="text/javascript">
176c94a4	22	var data = [];
05a1d116	23	for (var i = 0; i < 120; i++) {
176c94a4 DV	24	data.push([i,
	25	i / 5.0 + 10.0 * Math.sin(i / 3.0),
	26	30.0 - i / 5.0 - 10.0 * Math.sin(i / 3.0 + 1.0)]);
05a1d116 DV	27	}
	28
	29	g = new Dygraph(
	30	document.getElementById("demodiv"),
	31	data,
	32	{
176c94a4	33	labels: ['X', 'Y1', 'Y2'],
05a1d116	34	underlayCallback: drawLines,
de0445fc	35	drawPoints: true,
176c94a4	36	strokeWidth: 0.0
05a1d116 DV	37	}
	38	);
	39
	40	// coefficients of regression for each series.
	41	// if coeffs = [ null, [1, 2], null ] then we draw a regression for series 1
	42	// only. The regression line is y = 1 + 2 * x.
	43	var coeffs = [ null, null, null ];
	44	function regression(series) {
	45	// Only run the regression over visible points.
	46	var range = g.xAxisRange();
	47
	48	var sum_xy = 0.0, sum_x = 0.0, sum_y = 0.0, sum_x2 = 0.0, num = 0;
	49	for (var i = 0; i < g.numRows(); i++) {
	50	var x = g.getValue(i, 0);
	51	if (x < range[0] \|\| x > range[1]) continue;
	52
	53	var y = g.getValue(i, series);
	54	if (y == null) continue;
c5a37449 DV	55	if (y.length == 2) {
	56	// using fractions
	57	y = y[0] / y[1];
	58	}
05a1d116 DV	59
	60	num++;
	61	sum_x += x;
	62	sum_y += y;
	63	sum_xy += x * y;
	64	sum_x2 += x * x;
	65	}
	66
	67	var a = (sum_xy - sum_x * sum_y / num) / (sum_x2 - sum_x * sum_x / num);
	68	var b = (sum_y - a * sum_x) / num;
	69
	70	coeffs[series] = [b, a];
4df1af70	71	if (typeof(console) != 'undefined') {
2a07b0ad DV	72	console.log("coeffs(" + series + "): [" + b + ", " + a + "]");
2a07b0ad DV	73	}
05a1d116 DV	74
	75	g.updateOptions({}); // forces a redraw.
	76	}
	77
	78	function clearLines() {
	79	for (var i = 0; i < coeffs.length; i++) coeffs[i] = null;
	80	g.updateOptions({});
	81	}
	82
0a171c09 DV	83	function toHex(rgb) {
	84	return 'rgb(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ')';
	85	}
	86
05a1d116 DV	87	function drawLines(ctx, area, layout) {
	88	if (typeof(g) == 'undefined') return; // won't be set on the initial draw.
	89
	90	var range = g.xAxisRange();
	91	for (var i = 0; i < coeffs.length; i++) {
	92	if (!coeffs[i]) continue;
	93	var a = coeffs[i][1];
	94	var b = coeffs[i][0];
	95
	96	var x1 = range[0];
	97	var y1 = a * x1 + b;
	98	var x2 = range[1];
	99	var y2 = a * x2 + b;
	100
	101	var p1 = g.toDomCoords(x1, y1);
	102	var p2 = g.toDomCoords(x2, y2);
	103
0a171c09	104	var c = Dygraph.toRGB_(g.getColors()[i - 1]);
34bbe78b DV	105	c.r = Math.floor(255 - 0.5 * (255 - c.r));
	106	c.g = Math.floor(255 - 0.5 * (255 - c.g));
	107	c.b = Math.floor(255 - 0.5 * (255 - c.b));
0a171c09	108	var color = toHex(c);
05a1d116 DV	109	ctx.save();
	110	ctx.strokeStyle = color;
	111	ctx.lineWidth = 1.0;
	112	ctx.beginPath();
	113	ctx.moveTo(p1[0], p1[1]);
	114	ctx.lineTo(p2[0], p2[1]);
	115	ctx.closePath();
	116	ctx.stroke();
	117	ctx.restore();
	118	}
	119	}
	120
	121	</script>
	122
	123	<div style="position: absolute; left: 500px; top: 150px;">
	124	<input type=button style="color: green;" value="Regression (Y1)" onClick="regression(1)" />
	125	<br/><br/>
	126	<input type=button style="color: blue;" value="Regression (Y2)" onClick="regression(2)" />
	127	<br/><br/>
	128	<input type=button value="Clear Lines" onClick="clearLines()" />
	129	</div>
	130	</body>
	131	</html>