Recreation of wikipedia's gamma distribution plots in d3.
Powered using d3.js, jStat, and d3-legend.
Built with blockbuilder.org.
| <!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> | |
| <style> | |
| body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; } | |
| 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: #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 = 1000; | |
| var p = 0.001; | |
| var gamma = function(shape, scale){ | |
| return { | |
| "cdf": function(x){ return jStat.gamma.cdf(x, shape, scale); }, | |
| "pdf": function(x){ return jStat.gamma.pdf(x, shape, scale); }, | |
| "inv": function(p){ return jStat.gamma.inv(p, shape, scale); }, | |
| "label": "Gamma(α = " + shape + ", θ = " + scale + ")" | |
| }; | |
| } | |
| var lognormal = function(mu, sigma){ | |
| return { | |
| "cdf": function(x){ return jStat.lognormal.inv(x, mu, sigma); }, | |
| "pdf": function(x){ return jStat.lognormal.pdf(x, mu, sigma); } | |
| }; | |
| } | |
| var dists = [ | |
| gamma(1, 2), | |
| gamma(2, 2), | |
| gamma(3, 2), | |
| gamma(5, 1), | |
| gamma(9, 0.5), | |
| gamma(7.5, 1) | |
| ] | |
| var x = d3.scale.linear() | |
| .range([0, width / 2]) | |
| .domain([0, d3.max(dists.map(function(dist){ | |
| return dist.inv(1 - p); | |
| }))]) | |
| .nice(); | |
| var points = d3.range(x.domain()[0], | |
| x.domain()[1], p); | |
| 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", "x axis") | |
| .attr("transform", "translate(0,0)") | |
| .call(y1Axis); | |
| svg2.append("g") | |
| .attr("class", "x axis") | |
| .attr("transform", "translate(0,0)") | |
| .call(y2Axis); | |
| 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(d3.range(0, 20, p)); }) | |
| .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(d3.range(0, 20, p)); }) | |
| .attr("stroke", function(dist, i){ return color(i); }); | |
| svg1.append("g") | |
| .attr("class", "legendOrdinal") | |
| .attr("transform", "translate(" + (width / 4) + ",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); | |
| </script> | |
| </body> |