mirror of
https://github.com/kuhyx/testsAndMisc.git
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Krzysztof kuhy Rudnicki
3babda92d2
The Vite/React/TS dice solver had no git history yet. Commit it alongside a run.sh that ensures Node/pnpm are present, installs deps, and starts the dev server with a single command. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
39 lines
1.2 KiB
TypeScript
39 lines
1.2 KiB
TypeScript
/**
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* Seeded pseudo-random number generator (mulberry32).
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*
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* `Math.random` is deliberately not used anywhere in this project: the Monte
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* Carlo turn simulator and the search's random restarts both need to be
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* reproducible so their tests can assert exact numbers instead of tolerances.
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*/
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/** A function returning the next value in [0, 1). */
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export type Random = () => number;
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/**
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* Create a deterministic random source.
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*
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* @param seed - Any 32-bit integer; the same seed always yields the same stream.
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* @returns A function producing successive values in [0, 1).
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*/
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export function mulberry32(seed: number): Random {
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let state = seed >>> 0;
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return () => {
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state = (state + 0x6d2b79f5) >>> 0;
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let t = state;
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t = Math.imul(t ^ (t >>> 15), t | 1);
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t ^= t + Math.imul(t ^ (t >>> 7), t | 61);
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return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
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};
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}
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/**
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* Pick a random integer in `[0, bound)`.
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*
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* @param random - Source of randomness.
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* @param bound - Exclusive upper bound, must be positive.
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* @returns An integer in the half-open range.
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*/
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export function randomInt(random: Random, bound: number): number {
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return Math.floor(random() * bound);
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}
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