[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 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
	1	<!DOCTYPE html>
	2	<html>
	3	<head>
	4	<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7; IE=EmulateIE9">
	5	<title>Linear Regression</title>
	6	<!--[if IE]>
	7	<script type="text/javascript" src="../excanvas.js"></script>
	8	<![endif]-->
	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
	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">
	29	var data = [];
	30	for (var i = 0; i < 120; i++) {
	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)]);
	34	}
	35
	36	g = new Dygraph(
	37	document.getElementById("demodiv"),
	38	data,
	39	{
	40	labels: ['X', 'Y1', 'Y2'],
	41	underlayCallback: drawLines,
	42	drawPoints: true,
	43	strokeWidth: 0.0
	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 toHex(rgb) {
	91	return 'rgb(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ')';
	92	}
	93
	94	function drawLines(ctx, area, layout) {
	95	if (typeof(g) == 'undefined') return; // won't be set on the initial draw.
	96
	97	var range = g.xAxisRange();
	98	for (var i = 0; i < coeffs.length; i++) {
	99	if (!coeffs[i]) continue;
	100	var a = coeffs[i][1];
	101	var b = coeffs[i][0];
	102
	103	var x1 = range[0];
	104	var y1 = a * x1 + b;
	105	var x2 = range[1];
	106	var y2 = a * x2 + b;
	107
	108	var p1 = g.toDomCoords(x1, y1);
	109	var p2 = g.toDomCoords(x2, y2);
	110
	111	var c = Dygraph.toRGB_(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 = toHex(c);
	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>