# deterministic-random-sequence > A function that returns a sequence of deterministic random numbers Latest version **1.0.6** (published 2022-07-28) · MIT license · 0 weekly downloads ## Install ```sh npm install deterministic-random-sequence pnpm add deterministic-random-sequence yarn add deterministic-random-sequence bun add deterministic-random-sequence ``` ## Health **Score 20/100 (F)** — status: abandoned. Positive: esm support; no vulnerabilities. Warnings: low downloads; no types. Negative: abandoned; low maintenance score. ## Facts | | | |---|---| | Version | 1.0.6 | | Published | 2022-07-28 | | First published | 2021-07-06 | | Weekly downloads | 0 | | License | MIT | | TypeScript types | none | | Module format | ESM + CommonJS | | Dependencies | 0 | | Unpacked size | 7.7 KB | | Known vulnerabilities | 0 | | Install scripts | no | | GitHub stars | 3 | | Author | Paul Browne | | Maintainers | paul-browne | | Keywords | deterministic, random, sequence, prand, pseudo, number, PRNG | ## Links - npm: https://www.npmjs.com/package/deterministic-random-sequence - Repository: https://github.com/Paul-Browne/npm-deterministic-random-sequence - Homepage: https://github.com/Paul-Browne/npm-deterministic-random-sequence#readme - Issues: https://github.com/Paul-Browne/npm-deterministic-random-sequence/issues - npm.io page: https://npm.io/package/deterministic-random-sequence ## Alternatives - [random-seedable](https://npm.io/package/random-seedable.md) — 27.9K weekly downloads - [n2words](https://npm.io/package/n2words.md) — 22.2K weekly downloads - [@stdlib/math-base-special-factorialln](https://npm.io/package/@stdlib/math-base-special-factorialln.md) — 5.7K weekly downloads - [@stdlib/math-base-special-abs2](https://npm.io/package/@stdlib/math-base-special-abs2.md) — 1.7K weekly downloads - [commons-math-interpolation](https://npm.io/package/commons-math-interpolation.md) — 1.4K weekly downloads ## Recent versions - 1.0.6 (latest) — 2022-07-28 - 1.0.5 — 2021-07-07 - 1.0.4 — 2021-07-07 - 1.0.3 — 2021-07-07 - 1.0.2 — 2021-07-06 - 1.0.1 — 2021-07-06 - 1.0.0 — 2021-07-06 ## README # deterministic random sequence A function that returns a sequence of deterministic random numbers. Given the same seed the function will return the same order of random numbers. This uses the [MurmurHash3](https://en.wikipedia.org/wiki/MurmurHash) hashing function and the [sfc32](http://pracrand.sourceforge.net/) (Simple Fast Counter) which is part of the [PractRand](http://pracrand.sourceforge.net/) random number testing suite (which it passes of course). sfc32 has a 128-bit state and is very fast in JS. ### usage `npm i deterministic-random-sequence` or `npm i -D deterministic-random-sequence` ```js import drs from "deterministic-random-sequence"; const rand = drs("hello"); // "hello" seed, optional (will seed with "" if not set) const first = rand(); // 0.6173389465548098 const second = rand(); // 0.8618584796786308 const third = rand(); // 0.18602279876358807 // creates the same sequence from same initial conditions. const rand2 = drs("hello"); const fourth = rand2(); // 0.6173389465548098 const fifth = rand2(); // 0.8618584796786308 const sixth = rand2(); // 0.18602279876358807 ``` ### performance and randomness Stats for generating 10 million numbers eg. ```js import drs from "deterministic-random-sequence"; const rand = drs("hello"); const calls = () => { const time = Date.now(); for(let j = 0; j < 10000000; j++){ rand(); } return Date.now() - time; } const callsPushedToArray = () => { const time = Date.now(); const arr = []; for(let j = 0; j < 10000000; j++){ arr.push(rand()); } return Date.now() - time; } // 10 million calls to the rand() function, averaged of 100 times let averageTimeCalls = 0; for(let k = 0; k < 100; k++){ averageTimeCalls += calls(); } averageTimeCalls /= 100; // 10 million calls to the rand() function, pushed to an array, averaged of 100 times let averageTimeCallsPushedToArray = 0; for(let k = 0; k < 100; k++){ averageTimeCallsPushedToArray += callsPushedToArray(); } averageTimeCallsPushedToArray /= 100; // distribution of randomness let average = 0; const dist = {}; for(let j = 0; j < 10000000; j++){ const r = rand(); const key = Math.floor(r * 100)/100; const keyName = key.toFixed(2) + "-" + (key + 0.01).toFixed(2); if(dist[keyName]){ dist[keyName] = dist[keyName] + 1; }else{ dist[keyName] = 1; } average += r; } average /= 10000000; console.log({ averageTimeCalls, averageTimeCallsPushedToArray, dist, average }); ``` #### results 10 million calls (Macbook pro 2017, 16Gb ram, i5 processor), Average of 100 runs. ```js { averageTimeCalls: 35.53, // 0.03553 seconds averageTimeCallsPushedToArray: 219.99, // 0.21999 seconds dist: { '0.72-0.73': 99958, '0.83-0.84': 100553, '0.52-0.53': 100063, '0.56-0.57': 99678, '0.60-0.61': 100292, '0.87-0.88': 99739, '0.78-0.79': 99939, '0.46-0.47': 99975, '0.21-0.22': 99731, '0.97-0.98': 100231, '0.27-0.28': 100091, '0.62-0.63': 100112, '0.67-0.68': 99869, '0.11-0.12': 100378, '0.59-0.60': 99819, '0.70-0.71': 99457, '0.61-0.62': 100117, '0.99-1.00': 99615, '0.43-0.44': 100276, '0.19-0.20': 99686, '0.44-0.45': 100114, '0.17-0.18': 99790, '0.65-0.66': 99896, '0.73-0.74': 99668, '0.03-0.04': 100539, '0.89-0.90': 99506, '0.49-0.50': 99549, '0.71-0.72': 100020, '0.68-0.69': 99928, '0.12-0.13': 100131, '0.98-0.99': 100378, '0.16-0.17': 100245, '0.39-0.40': 99734, '0.93-0.94': 100071, '0.13-0.14': 100331, '0.80-0.81': 100200, '0.28-0.29': 99987, '0.47-0.48': 99730, '0.53-0.54': 100218, '0.35-0.36': 100209, '0.31-0.32': 100039, '0.06-0.07': 100321, '0.66-0.67': 100058, '0.76-0.77': 100152, '0.37-0.38': 99835, '0.00-0.01': 100340, '0.55-0.56': 99886, '0.88-0.89': 100105, '0.25-0.26': 99727, '0.58-0.59': 99819, '0.30-0.31': 99575, '0.18-0.19': 100106, '0.26-0.27': 99859, '0.85-0.86': 99875, '0.75-0.76': 99762, '0.94-0.95': 99846, '0.33-0.34': 99944, '0.38-0.39': 99790, '0.48-0.49': 100566, '0.74-0.75': 99909, '0.24-0.25': 100012, '0.20-0.21': 99633, '0.92-0.93': 99684, '0.15-0.16': 100058, '0.42-0.43': 100269, '0.41-0.42': 99463, '0.02-0.03': 99448, '0.07-0.08': 100346, '0.95-0.96': 100466, '0.04-0.05': 99505, '0.69-0.70': 99883, '0.81-0.82': 99587, '0.08-0.09': 100137, '0.50-0.51': 99707, '0.90-0.91': 100206, '0.54-0.55': 100296, '0.51-0.52': 99838, '0.09-0.10': 100034, '0.64-0.65': 99765, '0.32-0.33': 100026, '0.77-0.78': 99239, '0.84-0.85': 99884, '0.57-0.58': 100010, '0.45-0.46': 100505, '0.34-0.35': 99567, '0.86-0.87': 99842, '0.05-0.06': 100256, '0.23-0.24': 100428, '0.63-0.64': 99648, '0.82-0.83': 100151, '0.79-0.80': 100216, '0.01-0.02': 100072, '0.29-0.30': 100377, '0.91-0.92': 100296, '0.36-0.37': 100220, '0.40-0.41': 99927, '0.10-0.11': 100350, '0.22-0.23': 100491, '0.96-0.97': 100347, '0.14-0.15': 100474 }, average: 0.4998805594122014 } ``` --- _Source: https://npm.io/package/deterministic-random-sequence · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._