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

<html>
  <head>
    <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
05a1d116 DV	1	<html>
	2	<head>
	3	<title>Linear Regression</title>
	4	<!--[if IE]>
a2b2c3a1	5	<script type="text/javascript" src="../excanvas.js"></script>
05a1d116 DV	6	<![endif]-->
	7	<script type="text/javascript" src="../strftime/strftime-min.js"></script>
	8	<script type="text/javascript" src="../rgbcolor/rgbcolor.js"></script>
	9	<script type="text/javascript" src="../dygraph-canvas.js"></script>
	10	<script type="text/javascript" src="../dygraph.js"></script>
	11	<style type="text/css">
	12	body { max-width: 640 px; }
	13	</style>
	14	</head>
	15	<body>
	16	<h2>Linear Regression Demo</h2>
	17	<p>Click the buttons to generate linear regressions over either data
	18	series. If you zoom in and click the regression button, the regression will
	19	only be run over visible points. Zoom back out to see what the local
	20	regression looks like over the full data.</p>
	21
	22	<div id="demodiv" style="width: 480px; height: 320px;"></div>
	23
	24	<script type="text/javascript">
0a61ee86	25	var data = "X,Y1,Y2\n";
05a1d116	26	for (var i = 0; i < 120; i++) {
0a61ee86 DV	27	// data.push([i,
	28	// i / 5.0 + 10.0 * Math.sin(i / 3.0),
	29	// 30.0 - i / 5.0 - 10.0 * Math.sin(i / 3.0 + 1.0)]);
	30	data += i + "," + i + "/120," + (i(120-i)) + "/" + (6060) + "\n";
05a1d116 DV	31	}
	32
	33	g = new Dygraph(
	34	document.getElementById("demodiv"),
	35	data,
	36	{
05a1d116	37	underlayCallback: drawLines,
de0445fc	38	drawPoints: true,
0a61ee86 DV	39	strokeWidth: 0.0,
	40	fractions: true,
	41	errorBars: true
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
c5a37449 DV	102	// Scale up to percentages, rather than fractions.
	103	y1 *= 100;
	104	y2 *= 100;
	105
05a1d116 DV	106	var p1 = g.toDomCoords(x1, y1);
	107	var p2 = g.toDomCoords(x2, y2);
	108
34bbe78b DV	109	var c = new RGBColor(g.getColors()[i - 1]);
	110	c.r = Math.floor(255 - 0.5 * (255 - c.r));
	111	c.g = Math.floor(255 - 0.5 * (255 - c.g));
	112	c.b = Math.floor(255 - 0.5 * (255 - c.b));
	113	var color = c.toHex();
05a1d116 DV	114	ctx.save();
	115	ctx.strokeStyle = color;
	116	ctx.lineWidth = 1.0;
	117	ctx.beginPath();
	118	ctx.moveTo(p1[0], p1[1]);
	119	ctx.lineTo(p2[0], p2[1]);
	120	ctx.closePath();
	121	ctx.stroke();
	122	ctx.restore();
	123	}
	124	}
	125
	126	</script>
	127
	128	<div style="position: absolute; left: 500px; top: 150px;">
	129	<input type=button style="color: green;" value="Regression (Y1)" onClick="regression(1)" />
	130	<br/><br/>
	131	<input type=button style="color: blue;" value="Regression (Y2)" onClick="regression(2)" />
	132	<br/><br/>
	133	<input type=button value="Clear Lines" onClick="clearLines()" />
	134	</div>
	135	</body>
	136	</html>