pack layout

<!DOCTYPE html>
<meta charset="utf-8">
<style>

text {
  font: 10px sans-serif;
  text-anchor: middle;
}

.node--hover circle {
  stroke: #000;
  stroke-width: 1.2px;
}

</style>
<svg width="960" height="960"><g transform="translate(1,1)"></g></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>

var svg = d3.select("svg"),
    width = +svg.attr("width"),
    height = +svg.attr("height");

var format = d3.format(",d");

var color = d3.scaleSequential(d3.interpolateMagma)
    .domain([-4, 4]);

var stratify = d3.stratify()
    .parentId(function(d) { return d.id.substring(0, d.id.lastIndexOf(".")); });

var pack = d3.pack()
    .size([width - 2, height - 2])
    .padding(3);

d3.csv("flare.csv", function(error, data) {
  if (error) throw error;

var root = stratify(data)
      .sum(function(d) { return d.value; })
      .sort(function(a, b) { return b.value - a.value; });

pack(root);

node.append("circle")
      .attr("id", function(d) { return "node-" + d.id; })
      .attr("r", function(d) { return d.r; })
      .style("fill", function(d) { return color(d.depth); });

var leaf = node.filter(function(d) { return !d.children; });

leaf.append("clipPath")
      .attr("id", function(d) { return "clip-" + d.id; })
    .append("use")
      .attr("xlink:href", function(d) { return "#node-" + d.id + ""; });

leaf.append("text")
      .attr("clip-path", function(d) { return "url(#clip-" + d.id + ")"; })
    .selectAll("tspan")
    .data(function(d) { return d.id.substring(d.id.lastIndexOf(".") + 1).split(/(?=[A-Z][^A-Z])/g); })
    .enter().append("tspan")
      .attr("x", 0)
      .attr("y", function(d, i, nodes) { return 13 + (i - nodes.length / 2 - 0.5) * 10; })
      .text(function(d) { return d; });

node.append("title")
      .text(function(d) { return d.id + "\n" + format(d.value); });
});

function hovered(hover) {
  return function(d) {
    d3.selectAll(d.ancestors().map(function(d) { return d.node; })).classed("node--hover", hover);
  };
}

</script>

https://d3js.org/d3.v4.min.js