Non-negative Distributions

README.md

Visualization of non-negative distribution plots in d3.

Powered using d3.js, jStat, and d3-legend.

Built with blockbuilder.org.

forked from SpaceActuary's block: Distributions

distributions.js

var gammaDist = function(){
  
  var gamma = {},
      shape, 
      scale;
  
  var labeler = function(shape, scale){
    return "Gamma(α = " + d3.round(shape, 3) + ", " + 
      			     "θ = " + d3.round(scale, 3) + ")";
  }
  
  gamma.shape = function(_) {
    if (!arguments.length) return shape;
    shape = _;
    gamma.label = labeler(shape, scale);
    return gamma;
  };

  gamma.scale = function(_) {
    if (!arguments.length) return scale;
    scale = _;
    gamma.label = labeler(shape, scale);
    return gamma;
  };

  gamma.mean = function(_) {
    if (!arguments.length) return jStat.gamma.mean(shape, scale);
    scale = _ / shape;
    gamma.label = labeler(shape, scale);
    return gamma;
  };

  gamma.pdf = function(x){ return jStat.gamma.pdf(x, shape, scale); }      
  gamma.cdf = function(x){ return jStat.gamma.cdf(x, shape, scale); }
  gamma.inv = function(p){ return jStat.gamma.inv(p, shape, scale); }
  
  return gamma;
}

var lognormalDist = function(){
  
  var lognormal = {},
      mu, 
      sigma;
  
  var labeler = function(mu, sigma){
    return "Lognormal(μ = " + d3.round(mu, 3) + ", " + 
    								 "σ = " + d3.round(sigma, 3) + ")";
  }
  
  lognormal.mu = function(_) {
    if (!arguments.length) return mu;
    mu = _;
    lognormal.label = labeler(mu, sigma);
    return lognormal;
  };

  lognormal.sigma = function(_) {
    if (!arguments.length) return sigma;
    sigma = _;
    lognormal.label = labeler(mu, sigma);
    return lognormal;
  };

  lognormal.mean = function(_) {
    if (!arguments.length) return jStat.lognormal.mean(mu, sigma);
    mu = Math.log(_) - (sigma * sigma) / 2;
    lognormal.label = labeler(mu, sigma);
    return lognormal;
  };

  lognormal.pdf = function(x){ return jStat.lognormal.pdf(x, mu, sigma); }      
  lognormal.cdf = function(x){ return jStat.lognormal.cdf(x, mu, sigma); }
  lognormal.inv = function(p){ return jStat.lognormal.inv(p, mu, sigma); }
  
  return lognormal;
}


var paretoDist = function(){
  
  var pareto = {}, 
      scale,
      shape;
  
  var labeler = function(scale, shape){
    return "Pareto(x_m = " + d3.round(scale, 3) + ", " + 
    			 "α = " + d3.round(shape, 3) + ")";
  }
  
  pareto.shape = function(_) {
    if (!arguments.length) return shape;
    shape = _;
    pareto.label = labeler(scale, shape);
    return pareto;
  };

  pareto.scale = function(_) {
    if (!arguments.length) return scale;
    scale = _;
    pareto.label = labeler(scale, shape);
    return pareto;
  };

  pareto.mean = function(_) {
    if (!arguments.length) return jStat.pareto.mean(scale, shape);
    scale = _  * (shape - 1) / shape;
    pareto.label = labeler(scale, shape);
    return pareto;
  };

  pareto.pdf = function(x){ return jStat.pareto.pdf(x, scale, shape); }      
  pareto.cdf = function(x){ return jStat.pareto.cdf(x, scale, shape); }
  pareto.inv = function(p){ return jStat.pareto.inv(p, scale, shape); }
  
  return pareto;
}

var weibullDist = function(){
  
  var weibull = {}, 
      scale,
      shape;
  
  var labeler = function(scale, shape){
    return "Weibull(λ = " + d3.round(scale, 3) + ", " + 
    							 "k = " + d3.round(shape, 3) + ")";
  }
  
  weibull.shape = function(_) {
    if (!arguments.length) return shape;
    shape = _;
    weibull.label = labeler(scale, shape);
    return weibull;
  };

  weibull.scale = function(_) {
    if (!arguments.length) return scale;
    scale = _;
    weibull.label = labeler(scale, shape);
    return weibull;
  };

  weibull.mean = function(_) {
    if (!arguments.length) return jStat.weibull.mean(scale, shape);
    scale = _ / jStat.gammafn(1 + 1/shape);
    weibull.label = labeler(scale, shape);
    return weibull;
  };

  weibull.pdf = function(x){ return jStat.weibull.pdf(x, scale, shape); }      
  weibull.cdf = function(x){ return jStat.weibull.cdf(x, scale, shape); }
  weibull.inv = function(p){ return jStat.weibull.inv(p, scale, shape); }
  
  return weibull;
}

index.html

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
  <script src="https://cdn.jsdelivr.net/jstat/1.5.0/jstat.min.js"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/d3-legend/1.6.0/d3-legend.js"></script>
  <script src="distributions.js"></script>
  <style>
    body { 
      margin: 0;
      position: fixed;
      top: 0; right: 0; bottom: 0; left: 0; 
      font-family: Arial, Helvetica, sans-serif
    }
    svg { 
      width: 100%; 
      height: 100%; 
    }
    
    path {
stroke-width: 1;
fill: none;
    }
    .axis { 
      /*stroke: lightgrey;*/
      shape-rendering: crispEdges; 
    }
    
    .x.axis line { stroke: lightgrey; }

    .x.axis .minor { stroke-opacity: .5; }

    .x.axis path { stroke: lightgrey; }

    .y.axis line, .y.axis path {
      fill: none;
      stroke: lightgrey;
    }
    
    .handle path {
      fill: silver;
      stroke: #000;
    }
  </style>
</head>

<body>
  <script>
    var margin = {top: 60, right: 20, bottom: 60, left: 50, inner: 60};
    var width = 960 - margin.left - margin.inner - margin.right;
    var height = 500 - margin.top - margin.bottom;
     
    
    var svg = d3.select("body").append("svg")
      .attr("width", width + margin.left + margin.right)
      .attr("height", height + margin.top + margin.bottom)
    
    var svg1 = svg.append("g")
      .attr("transform", "translate(" + margin.left + "," + margin.top + ")");
        
    var svg2 = svg.append("g")
      .attr("transform", "translate(" + (width/2 + margin.left + margin.inner) 
            + "," + margin.top + ")");

    var i = 300;
    var p = 0.01;
    
    var dists = [
      /*gamma(1, 2),
      gamma(2, 2),
      gamma(3, 2),*/
      gammaDist().shape(2.5).scale(2),
      //gammaDist().shape(5).scale(1),
      //gammaDist().shape(10).scale(0.5),
      //gammaDist().shape(20).scale(0.25),
      /*gamma(9, 0.5),
      gamma(7.5, 1)*/
      lognormalDist().mu(Math.log(5)-(0.25^2)/2).sigma(0.25),
      //lognormalDist().mu(Math.log(5)-(0.5^2)/2).sigma(0.5),
      paretoDist().shape(2.5).scale(2),
      weibullDist().shape(1.5).mean(5),
      weibullDist().shape(2.5).mean(5)
    ]
    //console.log("pareto mean", jStat.pareto.mean(2.5, 2))
    
    var x = d3.scale.linear()
    .range([0, width / 2])
    .domain([0, d3.max(dists.map(function(dist){
        return dist.inv(1 - p);
      }))])
      .nice()
      .clamp(true);
 
    var points = d3.range(x.domain()[0], x.domain()[1], 
                         (x.domain()[1] - x.domain()[0]) / i);
    
    var y1 = d3.scale.linear()
      .range([height, 0])
      .domain([0, d3.max(dists.map(function(dist){
        return d3.max(points, function(pt){ return dist.pdf(pt); })
      }))])
      .nice();
    
    var y2 = d3.scale.linear()
      .range([height, 0])
 	    .domain([0, 1]);
    
    var color = d3.scale.category10();

    var xAxis = d3.svg.axis().scale(x).orient("bottom");
    
    svg1.append("g")
        .attr("class", "x axis")
        .attr("transform", "translate(0," + height + ")")
        .call(xAxis);
    
    svg2.append("g")
        .attr("class", "x axis")
        .attr("transform", "translate(0," + height + ")")
       .call(xAxis);
    
    var y1Axis = d3.svg.axis().scale(y1).orient("left");
    var y2Axis = d3.svg.axis().scale(y2).orient("left");
    
    svg1.append("g")
        .attr("class", "y y1 axis")
        .attr("transform", "translate(0,0)")
        .call(y1Axis);
    svg2.append("g")
        .attr("class", "y y2 axis")
        .attr("transform", "translate(0,0)")
        .call(y2Axis);
    
    var brush = d3.svg.brush()
      .x(x)
      .extent([0, 0])
      .on("brush", brushed)
      .on("brushend", brushended);

    
    var pdf_line = function(dist){
      return d3.svg.line()
        .x(function(d) { return x(d); })
        .y(function(d) { return y1(dist.pdf(d)); })
        .interpolate("linear");
    }
    
    var cdf_line = function(dist){
      return d3.svg.line()
        .x(function(d) { return x(d); })
        .y(function(d) { return y2(dist.cdf(d)); })
        .interpolate("linear");
    }
    
    var pdf_lines = dists.map(pdf_line);
    var cdf_lines = dists.map(cdf_line);
    
    svg1.selectAll("path.pdf")
        .data(pdf_lines)
      .enter()
        .append("path")
        .attr("class", "pdf")
        .attr("d", function(dist){ return dist(points); })
        .attr("stroke", function(dist, i){ return color(i); });
        
    svg2.selectAll("path.cdf")
        .data(cdf_lines)
      .enter()
        .append("path")
        .attr("class", "cdf")
        .attr("d", function(dist){ return dist(points); })
        .attr("stroke", function(dist, i){ return color(i); });
    
    svg1.append("g")
        .attr("class", "legendOrdinal")
        .attr("transform", "translate(" + (width / 5) + ",20)");

    var legendOrdinal = d3.legend.color()
        .shape("circle")
        .shapeRadius(7)
        .shapePadding(10)
        .scale(color)
        .labels(dists.map(function(dist){ return dist.label; }));

    svg.select(".legendOrdinal")
      .call(legendOrdinal);

  var slider = svg1.append("g")
      .attr("class", "slider")
      .call(brush);

  slider.selectAll(".extent,.resize")
      .remove();

  slider.select(".background")
      .attr("height", height);

  var handle = slider.append("g")
      .attr("class", "handle")

  handle.append("path")
      .attr("d", d3.svg.symbol().type("triangle-up").size(200))
      .attr("transform", "translate(0," + (height + margin.bottom * 0.6) + ")")
  
  slider
      .call(brush.extent([5, 5]))
      .call(brush.event);

  function redraw(value, duration){
    
    dists = dists.map(function(d, i){
    //console.log(i, d);
      d.mean(value);  
      return d;
    })
    
    pdf_lines = dists.map(pdf_line);
    cdf_lines = dists.map(cdf_line);
    
    svg1.selectAll("path.pdf")
        .data(pdf_lines)
      .transition().duration(duration)
        .attr("d", function(dist){ return dist(points); });
    
    svg2.selectAll("path.cdf")
        .data(cdf_lines)
      .transition().duration(duration)
        .attr("d", function(dist){ return dist(points); });
    
    svg.select(".legendOrdinal")
        .call(legendOrdinal.labels(dists.map(function(dist){ 
          return dist.label; 
        })));
    
  }
  
  function rescale(value, duration){
    
    handle.transition().duration(duration)
      .attr("transform", "translate(" + x(value) + ",0)");
    
     /*
    y1.domain([0, d3.max(dists.map(function(dist){
        return d3.max(points, function(pt){ return dist.pdf(pt); })
      }))]);
    y1Axis.scale(y1);
    
    svg.selectAll("g.y1.axis").transition()
      .delay(duration)
      .duration(duration)
      .call(y1Axis);
    */
  }
    
  function brushed() {
    var value = brush.extent()[0];
    //console.log(value)
    if (d3.event.sourceEvent) { // not a programmatic event
      value = x.invert(d3.mouse(this)[0]);
      brush.extent([value, value]);
    }
    
    handle
      .attr("transform", "translate(" + x(value) + ",0)");
    
    redraw(value, 0)
    
  }
    
  function brushended() {
    
    var value = brush.extent()[0];
    
    if (!d3.event.sourceEvent) return; // only transition after input
   
    x = d3.scale.linear()
    .range([0, width / 2])
    .domain([0, d3.max(dists.map(function(dist){
        return dist.inv(1 - p);
      }))])
      .nice()
      .clamp(true);
 
    points = d3.range(x.domain()[0], x.domain()[1], 
                     (x.domain()[1] - x.domain()[0]) / i);
    
    xAxis.scale(x);
    
    svg.selectAll("g.x.axis").transition().duration(1500).call(xAxis);
   
    rescale(value, 1500)
    redraw(value, 1500)
    
  }
    
  </script>
</body>