Published
Edited
May 28, 2018
4 forks
14 stars
in_circle = ([x, y]) => x*x + y*y + 0.25 < x + y
halton = function halton (index, base) {
let fraction = 1;
let result = 0;
while (index > 0) {
fraction /= base;
result += fraction * (index % base);
index = ~~(index / base); // floor division
}
return result;
}
positional = function positional (number, base) {
const result = [];
while (number > 0) {
result.push(number % base);
number = ~~(number / base); // floor division
}
return result.reverse();
}
cube_points = n => d3.range(100, 100 + n).map(
i => [halton(i, 2), halton(i, 3), halton(i, 5)])
{
function* gen() {
for (let i = 100;; i++)
yield [halton(i, 2), halton(i, 3), halton(i, 5)];
}
const g = gen();
while (true)
yield Promises.delay(1000, g.next().value);
}
npts = 4000
data = [...Array(npts).keys()].map(
d => [halton(d, base1), halton(d, base2)])
coloring = (d, i) => d3.interpolatePurples(Math.pow(i/npts, 5))
plot = () => {
const svgwidth = Math.min(width, 600);
const margin = 20;
const svg = d3.select(DOM.svg(svgwidth, svgwidth));
const x = d3.scaleLinear()
.domain([0, 1])
.range([margin, svgwidth-margin]);
const y = d3.scaleLinear()
.domain([0, 1])
.range([svgwidth-margin, margin]);
const dots = svg.append("g").selectAll("circle")
.data(data.slice().reverse())
.enter().append("circle")
.attr("cx", d=>x(d[0]))
.attr("cy", d=>y(d[1]))
.attr("fill", coloring)
.attr("r", svgwidth / 150);
return svg.node();
}
plot()
randfloat = {
// Use a Multiply With Carry PRNG, with an XOR-shift successor
// Both from Numerical Recipes, 3rd Edition [H1, G1]
const prng = function* prng(seed) {
if (seed == null) seed = +new Date;
// these two numbers were arbitrarily chosen
let z, x = 3395989511 ^ seed, y = 1716319410 ^ seed;
while (true) {
x = 62904 * (x & 0xffff) + (x >>> 16);
y = 41874 * (y & 0xffff) + (y >>> 16);
z = (x << 16) + y;
z ^= z >>> 13; z ^= z << 17; z ^= z >>> 5;
yield z;
}
}
const POW_NEG_26 = Math.pow(2, -26);
const POW_NEG_27 = Math.pow(2, -27);
return function* randfloat(seed) {
const p = prng(seed);
while (true) {
const low_bits = p.next().value >>> 6;
const high_bits = p.next().value >>> 5;
yield (high_bits + low_bits * POW_NEG_26) * POW_NEG_27;
}
}
}
prngdata = {
const r = randfloat();
return d3.range(npts).map(d => [r.next().value, r.next().value]);
}
One platform to build and deploy the best data apps
Experiment and prototype by building visualizations in live JavaScript notebooks. Collaborate with your team and decide which concepts to build out.
Use Observable Framework to build data apps locally. Use data loaders to build in any language or library, including Python, SQL, and R.
Seamlessly deploy to Observable. Test before you ship, use automatic deploy-on-commit, and ensure your projects are always up-to-date.