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

<!DOCTYPE html>
<html>
  <head>
    <title>Linear Regression</title>
    <!--
    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
54425b14	1	<!DOCTYPE html>
05a1d116 DV	2	<html>
	3	<head>
	4	<title>Linear Regression</title>
7e5ddc94 DV	5	<!--
	6	For production (minified) code, use:
	7	<script type="text/javascript" src="dygraph-combined.js"></script>
	8	-->
	9	<script type="text/javascript" src="../dygraph-dev.js"></script>
	10
05a1d116 DV	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">
176c94a4	25	var data = [];
05a1d116	26	for (var i = 0; i < 120; i++) {
176c94a4 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)]);
05a1d116 DV	30	}
	31
	32	g = new Dygraph(
	33	document.getElementById("demodiv"),
	34	data,
	35	{
176c94a4	36	labels: ['X', 'Y1', 'Y2'],
05a1d116	37	underlayCallback: drawLines,
de0445fc	38	drawPoints: true,
176c94a4	39	strokeWidth: 0.0
05a1d116 DV	40	}
	41	);
	42
	43	// coefficients of regression for each series.
	44	// if coeffs = [ null, [1, 2], null ] then we draw a regression for series 1
	45	// only. The regression line is y = 1 + 2 * x.
	46	var coeffs = [ null, null, null ];
	47	function regression(series) {
	48	// Only run the regression over visible points.
	49	var range = g.xAxisRange();
	50
	51	var sum_xy = 0.0, sum_x = 0.0, sum_y = 0.0, sum_x2 = 0.0, num = 0;
	52	for (var i = 0; i < g.numRows(); i++) {
	53	var x = g.getValue(i, 0);
	54	if (x < range[0] \|\| x > range[1]) continue;
	55
	56	var y = g.getValue(i, series);
	57	if (y == null) continue;
c5a37449 DV	58	if (y.length == 2) {
	59	// using fractions
	60	y = y[0] / y[1];
	61	}
05a1d116 DV	62
	63	num++;
	64	sum_x += x;
	65	sum_y += y;
	66	sum_xy += x * y;
	67	sum_x2 += x * x;
	68	}
	69
	70	var a = (sum_xy - sum_x * sum_y / num) / (sum_x2 - sum_x * sum_x / num);
	71	var b = (sum_y - a * sum_x) / num;
	72
	73	coeffs[series] = [b, a];
4df1af70	74	if (typeof(console) != 'undefined') {
2a07b0ad DV	75	console.log("coeffs(" + series + "): [" + b + ", " + a + "]");
2a07b0ad DV	76	}
05a1d116 DV	77
	78	g.updateOptions({}); // forces a redraw.
	79	}
	80
	81	function clearLines() {
	82	for (var i = 0; i < coeffs.length; i++) coeffs[i] = null;
	83	g.updateOptions({});
	84	}
	85
0a171c09 DV	86	function toHex(rgb) {
	87	return 'rgb(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ')';
	88	}
	89
05a1d116 DV	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
0a171c09	107	var c = Dygraph.toRGB_(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));
0a171c09	111	var color = toHex(c);
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>