44:["$","title",null,{"children":"Guyou, Peirce, Adams, Spilhaus | Torben Jansen | Observable"}] 4c:Tc63,const speed = (() => { // Raw projections: f(lambda, phi) → [x, y], radians. // The third entry says whether the projection covers the whole sphere or only a hemisphere. const raws = [ ["Guyou - d3", d3gp.geoGuyouRaw, false], ["Guyou", guyouRaw, false], ["Adams hemisphere", adamsHemiRaw, false], ["Adams WS1", adams1_raw, true], ["Adams WS2", adams2_raw, true], ["Spilhaus", adams2_core, true] ]; // A fresh timer per measurement: new Function compiles separate code each time, // so the call site `f(...)` stays monomorphic. Returns the best ns per point over // several rounds; the sum (sink) keeps the calls from being optimised away. const makeTimer = () => new Function("f", "args", "rounds", ` let sink = 0; for (let r = 0; r < 2; ++r) { for (let i = 0; i < args.length; ++i) sink += f(args[i][0], args[i][1])[0]; // warm up } let best = Infinity; for (let r = 0; r < rounds; ++r) { const t = performance.now(); for (let i = 0; i < args.length; ++i) sink += f(args[i][0], args[i][1])[0]; best = Math.min(best, (performance.now() - t) / args.length * 1e6); } return {ns: best, sink}; `); const format = {"forward (ns)": (d) => d.toFixed(0), "inverse (ns)": (d) => d.toFixed(0)}; const nextFrame = () => new Promise((resolve) => setTimeout(resolve, 0)); async function benchmark(onProgress) { const hemispherePoints = randomPoints(200000, {hemisphere: true}); const spherePoints = randomPoints(200000); const rounds = 5; const best = new Map(); // Two passes in opposite order, to reduce order effects; keep the minimum. const order = [...raws, ...[...raws].reverse()]; for (const [i, [name, raw, whole]] of order.entries()) { onProgress(`Running ${name} (${i + 1}/${order.length}) …`); await nextFrame(); // let the browser repaint between measurements const points = whole ? spherePoints : hemispherePoints; const projected = points.map(([l, p]) => raw(l, p)); const forward = makeTimer()(raw, points, rounds).ns; const inverse = makeTimer()(raw.invert, projected, rounds).ns; const b = best.get(name) ?? {forward: Infinity, inverse: Infinity}; best.set(name, {forward: Math.min(b.forward, forward), inverse: Math.min(b.inverse, inverse)}); } return raws.map(([name]) => ({ "projection (raw)": name, "forward (ns)": best.get(name).forward, "inverse (ns)": best.get(name).inverse })); } // Button, status line and result table in one element; no reactivity involved. const button = html``; const status = html``; const result = html`

`; button.onclick = async () => { button.disabled = true; try { const rows = await benchmark((message) => status.textContent = message); result.replaceChildren(Inputs.table(rows, {format, layout: "fixed", select: false})); status.textContent = ""; } finally { button.disabled = false; } }; return html`

${button}${status}${result}

`; })(); display(speed);4d:T834,const width = 960, dpr = window.devicePixelRatio || 1; const sphere = {type: "Sphere"}; const projection = projections.get(controls.name)(); projection.fitWidth(width, sphere); const height = Math.ceil(d3.geoPath(projection).bounds(sphere)[1][1]); const canvas = display(html`