Chandrupatla’s root-finding methodSidi’s root-finding methodRegular numbersDruidJS workerNatural breaksDistance to a segmentRay out of a convex hullWord Tour: 40k words and their friendsHello, @thi.ng/grid-iteratorsHead/tail breaksPseudo-blue noise shaderHow fast does walk-on-spheres converge?AoC 12: shortest path under constraintsKDE estimationPlot: Correlation heatmapPoisson Finish 2Poisson disk sampling functionsWoS with transportSimple and surprising sortLocal medianTime series topological subsamplingUnion-FindLevel set experiment 1Mean value coordinatesPoisson potentialMiddle-squareWorld of squares (spherical)World of squaresHello, PyWaveletsGeothmetic meandianHello, Reorder.jsGeometric MedianImage FFTTransport to a mapDisc TransportTP3: Power Diagram and Semi-Discrete Optimal TransportThe blue waveHello, genetic-jsSliced Optimal TransportDruidJSSelf-Organizing Maps meet DelaunayHello, polygon-clippingseedrandom, minimalWalk on Spheres 2Walk on SpheresHello, AutoencoderKaprekar’s numberVoronoiMap2DHello, ccwt.jsPolygon TriangulationQuantile.invert?Linear congruential generatorHue blurNeedle in a haystackMoving average blurApollo 11 implementation of trigonometric functions, by Margaret H. Hamilton (march 1969)2D curves intersectionThe 2D approximate Newton-Raphson methodInverting Lee’s Tetrahedral projectionLinde–Buzo–Gray stipplingMean shift clustering with kd-tree2D point distributionsShortest pathKahan SummationHello, delatinDijkstra’s algorithm in gpu.jsLloyd’s relaxation on a graphManhattan DiameterManhattan VoronoiMobility landscapes — an introductionDijkstra’s shortest-path treeH3 odditiesProtein MatrixConvex Spectral WeightsSort stuff by similarityKrigingDelaunay.findTrianglen-dimensions binning?Travelling with a self-organizing mapUMAP-o-MaticMNIST & UMAP-jsHello UMAP-jsMean shift clusteringLevenshtein transitionRd quasi-random sequencesAutomated label placement (countries)Phyllotaxis explainedMotionrugsPlanar hull (Andrew’s monotone chain algorithm)South Africa’s medial axisTravelling salesperson approximation with t-SNEDistance to shoreWorkerngraph: pagerank, louvain…t-SNE VoronoiCloud ContoursCircular function drawingKruskal MazeMyceliumTravelling salesperson approximation on the globe, with t-SNEtsne.jstsne.js & worker
Largest Inscribed Square
path = svg`<path d="${d3.geoPath().projection(projection)(
world
)}" stroke=black fill=none>`
points = (replay,
d3.shuffle(
d3.range(0, path.getTotalLength(), sample).map((i) => {
const p = path.getPointAtLength(i);
return [p.x, p.y];
})
))
toeplitz = {
let min = 0;
let solution = [];
let candidates = [];
let steps = 0;
let k;
for (let i = 0; i < points.length; i++) {
for (let j = 0; j < i; j++) {
k = (i * (i + 1) + (j + 1)) / 2;
const a = points[i];
const b = points[j];
const dist2 = (a[0] - b[0]) ** 2 + (a[1] - b[1]) ** 2;
if (dist2 <= min) continue;
const m = [(a[0] + b[0]) / 2, (a[1] + b[1]) / 2]; // center
const n = [(b[1] - a[1]) / 2, (a[0] - b[0]) / 2]; // normal
const c = [m[0] - n[0], m[1] - n[1]];
const d = [m[0] + n[0], m[1] + n[1]];
if (steps++ % 100000 === 0)
yield {
test: [a, c, b, d],
solution,
candidates,
dist: Math.sqrt(min),
k
};
const t = testSquare(a, c, b, d);
if (t) {
min = dist2;
candidates.push((solution = t));
yield { test: t, solution: t, candidates, dist: Math.sqrt(min), k };
}
}
}
yield { test: [], solution, candidates, dist: Math.sqrt(min) };
}
quad = d3.quadtree(points)
sample = 1 // sample every pixel (try 3 for faster convergence)
function testSquare(a, c, b, d) {
c = quad.find(...c, sample);
if (c != null) {
d = quad.find(...d, sample);
if (d != null) {
return [a, c, b, d];
}
}
}
world = fetch("https://cdn.jsdelivr.net/npm/world-atlas@2/land-110m.json")
.then((d) => d.json())
.then((d) => topojson.feature(d, d.objects.land))
projection = d3.geoBertin1953().fitExtent(
[
[0, 0],
[width, height]
],
world
)
height = 600
d3 = require("d3@7", "d3-geo-projection@3")
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