Unirand

A JavaScript module for generating seeded random distributions and its statistical analysis.

Implemented in pure JavaScript with no dependencies, designed to work in Node.js and fully asynchronous, tested with 900+ tests.

Supported distributions

Name	Parameters	Usage
Uniform distribution	`min` - any value, `max` - any value, `min` < `max`	`unirand.uniform(min, max).random()`
Normal (Gaussian) distribution	`mu` - any value, `sigma` > 0	`unirand.normal(mu, sigma).random()`
Bates distribution	`n` - integer, `n` >= 1, `a` - any value, `b` - any value, `b` > `a`	`unirand.bates(n, a, b).random()`
Bernoulli distribution	`p` - float number, 0 <= `p` <= 1	`unirand.bernoulli(p).random()`
Beta distribution	`alpha` - integer, `alpha` > 0, `beta` > integer, `beta` > 0	`unirand.beta(alpha, beta).random()`
BetaPrime distribution	`alpha` - integer, `alpha` > 0, `beta` > integer, `beta` > 0	`unirand.betaprime(alpha, beta).random()`
Binomial distribution	`n` - integer, `n` > 0, `p` - float number, 0 <= `p` <= 1	`unirand.binomial(n, p).random()`
Cauchy (Lorenz) distribution	`x` - any value, `gamma` > 0	`unirand.cauchy(x, gamma).random()`
Chi distribution	`k` - integer, `k` > 0	`unirand.chi(k).random()`
Chi Square distribution	`k` - integer, `k` > 0	`unirand.chisquare(k).random()`
Compertz distribution	`nu` > 0 - float value, `b` > 0 - float value	`unirand.compertz(nu, b).random()`
Delaporte distribution	`alpha` > 0 - float value, `beta` > 0 - float value, `lambda` > 0 - float value	`unirand.delaporte(alpha, beta, lambda).random()`
Erlang distribution	`k` - integer, `k` > 0, `mu` - float value, `mu` > 0	`unirand.erlang(k, mu).random()`
Exponential distribution	`lambda` - float value, `lambda` > 0	`unirand.exponential(lambda).random()`
Extreme (Gumbel-type) Value distribution	`mu` - any value, `sigma` - float number, `sigma` > 0	`unirand.extremevalue(mu, sigma).random()`
Fatigue life distribution	`alpha` > 0, `beta` > 0	`unirand.fatigue(alpha, beta).random()`
Gamma distribution	`alpha` - float value, `alpha` > 0, `beta` - integer, `beta` > 0	`unirand.gamma(alpha, beta).random()`
Geometric distribution	`p` - float value, 0 <= `p` <= 1	`unirand.geometric(p).random()`
Irwin-Hall distribution	`n` - integer, `n` > 0	`unirand.irwinhall(n).random()`
Laplace distribution	`mu` - any value, `b` - float value, `b` > 0	`unirand.laplace(mu, b).random()`
Logistic distribution	`mu` - any value, `s` - float value, `s` > 0	`unirand.logistic(mu, s).random()`
Lognormal distribution	`mu` - any value, `sigma` - float value, `sigma` > 0	`unirand.lognormal(mu, sigma).random()`
Negative Binomial distribution	`r` - integer, `r` > 0, `p` - float value, 0 <= `p` <= 1	`unirand.negativebinomial(r, p).random()`
Pareto distribution	`xm` - float value, `xm` > 0, `alpha` - float value, `alpha` > 0	`unirand.pareto(xm, alpha).random()`
Poisson distribution	`lambda` - integer, `lambda` > 0	`unirand.poisson(lambda).random()`
Rayleigh distribution	`sigma` - float value, `sigma` > 0	`unirand.rayleigh(sigma).random()`
Student's t-distribution	`v` - integer, `v` > 0	`unirand.student(v).random()`
Triangular distribution	`a`, `b`, `c` - any number, `b` > `a`, `a` <= `c` <= `b`	`unirand.triangular(a, b, c).random()`
Weibull distribution	`k` - float value, `k` > 0, `lambda` - float value, `lambda` > 0	`unirand.weibull(k, lambda).random()`
Zipf distribution	`alpha` - float value, `alpha` >= 0, `shape` - integer, `shape` > 1	`unirand.zipf(alpha, shape).random()`

Installation and Usage

Install the unirand module, using npm install unirand, then include the code with require. The require method returns an object with all of the module's methods attached to it.

const unirand = require('unirand');

PRNG

Unirand supports different PRNGs: default JS generator, tuchei seeded generator. By default unirand uses tuchei generator. Our seeded generator supports seed, random, next methods. A name of current using PRNG is stored in:

unirand.prng.prng_name; // returns a name of current generator

Also you can set another PRNG by calling:

unirand.prng.set_prng('default'); // now PRNG is default JS generator equals to Math.random()

Unirand supports different PRNGs:

Name	Description	Performance	Supports seed
default	Default JS PRNG	fast	No
tuchei	Tuchei PRNG, period ~2³²	very fast	Yes
xorshift	Xorshift PRNG, period ~2³²	very fast	Yes
kiss	Kiss PRNG, period ~2¹²¹	fast	Yes
parkmiller	Park-Miller PRNG, period ~2³¹	medium	Yes
coveyou	Coveyou PRNG, period ~2³¹	slow	Yes
knuthran2	knuthran2 PRNG, period ~10¹⁸	slow	Yes
r250	r250 PRNG, period ~2²⁵⁰	very fast	Yes
mrg5	Fifth-order multiple recursive PRNG, period ~10⁴⁶	slow	Yes
gfsr4	gfsr4 PRNG, period ~2⁹⁶⁸⁹	fast	Yes
dx1597	Dx-1957-f PRNG, period ~10¹⁴⁹⁰³	slow	Yes
tt800	TT800 PRNG, period ~10²⁴⁰	medium	Yes
xorwow	Xorwow PRNG, period ~10³⁸	fast	Yes
mt19937	Marsenne Twister PRNG, period ~2¹⁹⁹³⁷	medium	Yes
philox	Philox 4x32 PRNG, period ~2¹⁹³	slow	Yes
swb2712	Swb2712 PRNG, period ~2¹⁴⁹²	fast	Yes
taus113	Tausworthe PRNG, period ~2¹¹³	very fast	Yes

.random(), .randomInt() and .randomInRange(from, to)

Returns random uniformly distributed value or array of length n. Returns different value each time without seed and same value with seed value.

unirand.random(); // random value [0, 1)
unirand.random(n); // uniformly distributed random array of length n

unirand.randomInt(); // random integer [0, 2^32)
unirand.randomInt(n); // uniformly distributed random integer array of size n 

unirand.randomInRange(from, to); // random value in range [from, to), from > to
unirand.randomInRange(from, to, n); // array of size n, each value is random in range [from, to), from > to

Without seed value this method returns different values each call. With seed value this method returns same value each time.

.next(), .nextInt() and .nextInRange(from, to)

It makes sense only for seeded generators. Otherwise, that method works as .random(). If you want to return another random seeded value after .random() method, use .next().

unirand.seed(123456);
unirand.random(); // returns 0.07329190103337169
unirand.random(); // returns same 0.07329190103337169
unirand.next(); // returns 0.49862336413934827
unirand.next(); // returns 0.045074593275785446
unirand.nextInRange(10, 20); // 12.58303941693157
unirand.nextInt(); // 1398469627
...

Same results for .nextInt() and .nextInRange(from, to). These methods always return single value.

*Note: for seeded prng we don't recommend use .random() method for generating all random values. Use .random() first time flushing generator, then .next() for all other random values.

.seed()

unirand.seed('unirand'); // sets seed value for PRNG
unirand.random(); // always 0.026891989167779684
unirand.normal(1, 1).randomSync(); // always -0.46754931268295974

After setting seed value unirand always will use this value for generating random values. If you want to reset seed use

unirand.seed(<new seed value>);

If you want to unset seed and generate different values each time use:

unirand.seed(); // unset seed value for all generators

PRNG Factory

Unirand allows you to generate independent PRNGs of all supported types.

let prng = newPrng(<prng name>[, <seed value>]); // unseeded by default

// example
prng = newPrng('r250');
prng.random(); // 0.6259469939395785
prng.random(); // 0.3127290401607752
prng.next();   // 0.10631363722495735

// you can generate seeded PRNG
prng = newPrng('tuchei', 'unirand');
prng.random();  // 0.026891989167779684
prng.random();  // same 0.026891989167779684
prng.next();    // 0.23777238093316555
prng.nextInt(); // 2513331331

Random number

Generates random number with given distribution. For example, if you want to generate random number with normal distribution:

let mu = 1,
    sigma = 2;
// Asynchronous call
unirand.normal(mu, sigma).random()
    .then((randomNumber) => {
        console.log(randomNumber);
    });
// Synchronous call
let randomNumber = unirand.normal(mu, sigma).randomSync();

// for seeded generator
let randomNext = unirand.normal(mu, sigma).nextSync();

For any generator .random() and .next() are asynchronous, while .randomSync() and .nextSync() - synchronous.

Random distribution

Generates random distribution (array with n random numbers). For example, if you want to generate random number with normal distribution:

let mu = 1,
    sigma = 2,
    n = 100;
// Asynchronous call
unirand.normal(mu, sigma).distribution(n)
    .then((randomDistribution) => {
        randomDistribution.map((randomNumber) => {
            console.log(randomNumber);
        });
    });
// Synchronous call
let randomArray = unirand.normal(mu, sigma).distributionSync(n);

For seeded generator returns same distribution each time. You still can use .next() or .nextSync() after this method.

Analyze

Analyze random distribution (Analyzer docs):

let analyzer = unirand.analyze(randomArray, {
    pdf: 1000 // default: 200
});
// Fully asynchronous
// Returns full analyzer object
analyzer.then((res) => {
    console.log(res);
    // returns {min, max, mean, median...} object
});
// Returns only one random array option
analyzer.entropy.then((res) => {
    console.log(res);
    // returns entropy value as a number
});

Sample

Generates random sample from array, string or object. This method will generate k random elements from array/string with n elements.

const sample = unirand.sample;
sample(<array|string|object>, <number|options object>, options object);

You can point k value (in this case .sample returns k-length result) or not (in this case .sample returns result with random length). Method will return random sample with same type as input. In case when k greater then input length method will return input. This method also allow shuffle output:

sample([1, 2, 3, 4, 5, 6, 7, 8, 9], 3) // will output [2, 5, 8], for example, or [1, 4, 9] - in ascending order by index
sample([1, 2, 3, 4, 5, 6, 7, 8, 9], 3, {shuffle: true}) // will output [6, 9, 1] or [3, 2, 7] - shuffled result
sample([1, 2, 3, 4, 5, 6, 7, 8, 9]) // will output [2, 5, 8], for example, or [1, 4, 7, 9] - random length, in ascending order by index
sample([1, 2, 3, 4, 5, 6, 7, 8, 9], {shuffle: true}) // will output [6, 9, 1] or [3, 2, 7, 4] - random length, shuffled result

Does not mutate input!

Sample method is 3 times faster for arrays and 7 times faster for string compared to simple shuffled and sliced array|string.

Shuffle

Shuffle array or string (O(n) time complexity)

const shuffle = unirand.shuffle;
shuffle(<array|string>); // will output random permutation of input

Method will return random permutation with same type as input.

Derange

Derange method returns random derangement of array or string (O(n) time complexity) Derangement is a permutation of the elements of a set, such that no element appears in its original position. In other words, derangement is a permutation that has no fixed points.

const derange = unirand.derange;
derange(<array|string>); // will output random derangement of input

There are approximately n!/e derangements for array with n elements.

Roulette wheel

Consider You have an array of elements represented by some weight w_i, and You want to select each element with probability w_i / <sum all weights>. You can use roulette wheel algorithm for that purpose:

// will create RouletteWheel instance with its own PRNG
const rouletteWheel = unirand.newRouletteWheel(<weights array>);
// weights array should be an array of positive numerical values
// weights array can be unsorted, weight can be any positive value

// @example
const rouletteWheel = unirand.newRouletteWheel([2, 1, 3]); // O(weights.length) time complexity
rouletteWheel.select(); // always O(1) time complexity
// method .select() will return index 0 with 33.33% probability
// method .select() will return index 1 with 16.67% probability
// method .select() will return index 2 with 50.00% probability

RouletteWheel .select() method will return a corresponding index of weights array with O(1) time complexity. As rouletteWheel instance has own prng attached, it supports additional options:

const rouletteWheel = unirand.newRouletteWheel([1, 2, 3], {
    prng: 'tt800', // supports all unirand's PRNG algorithms
    seed: 12345 // initial seed values, by default PRNG is unseeded
});

// PRNG options can be changed via next methods as well
rouletteWheel.seed(<seed value>);
rouletteWheel.seed(); // will unset seed from PRNG making PRNG unseeded
rouletteWheel.setPrng(<prng name>[, reset]); // will set new PRNG
// reset (default: false) will reset PRNG to initial state, useful to reproduce selections
rouletteWheel.reset(); // reset PRNG to initial state

String utils

Unirand allow You to generate different random strings:

Usage	Description	Example
unirand.stringutils.random('abcdefg', n)	Generates random string of size `n` with Your alphabet	`dbfagcdaeb`
unirand.stringutils.randomHex(n)	Generates random string of size `n` with `0123456789abcdef` alphabet	`ebe9a1d10d`
unirand.stringutils.randomAlphabetic(n)	Generates random string of size `n` with [a-z, A-Z] alphabet	`LfeFYWVjDH`
unirand.stringutils.randomAscii(n)	Generates random string of size `n` with ASCII alphabet	`&TxiHCFN<d`
unirand.stringutils.randomAlphanumeric(n)	Generates random string of size `n` with [a-z, A-Z, 0-9] alphabet	`r4A77w1fo0`
unirand.stringutils.randomNumeric(n)	Generates random string of size `n` with [0-9] alphabet	`3826717859`
unirand.stringutils.randomBitString(n, p)	Generates random string of size `n` consists of only `1` or `0` with `p` probability of `1` (default `p=0.5`)	`1101100011`
unirand.stringutils.randomUID(type)	Generates random UID of type `type` (see UID generation)	`3b6d5575-1a03-40a8-9cd2-e1493dbe5d01`

For seeded PRNGs You can use .next* methods:

unirand.seed('unirand');
unirand.stringutils.randomAscii(15); // "6W5,Wj8JeZsz"$
unirand.stringutils.randomAscii(15); // "6W5,Wj8JeZsz"$
unirand.stringutils.nextAscii(15); // 20wv]+m)!p;+;t=
unirand.stringutils.nextAscii(15); // CM6-BgKAj;O>8TK

*Note: not all UID generators will generate same UID for seeded PRNGs.

UID generation

You can generate random UID of different types. Not all of them can be seeded. unirand.stringutils.randomUID('uuid') and unirand.uid('uuid').random() are the same:

Name	Usage	Description	Randomness	Example
betterguid	unirand.uid('betterguid').random()	8 bytes of time (milliseconds) + 9 random bytes	Partly random	`-MJvUyyWjbsx01BAu`
ksuid	unirand.uid('ksuid').random()	4 bytes of time (seconds) + 16 random bytes	Partly random	`DBnbYgY8lToilslDcryc4PQFCjE`
uuid	unirand.uid('uuid').random()	UUIDv4 from RFC 4112, 4 bytes for time in milliseconds, other 12 bytes - random	Partly random	`3b834ec5-0383-428b-b6b9-de0022dd91c1`
shortuuid	unirand.uid('shortuuid').random()	Short representation of UUIDv4	Partly random	`8mkdCaDhVxg9TV48shm1ZX`
sno	unirand.uid('sno').random()	5 bytes timestamp, 3 bytes random payload, 2 bytes increased (with any call) sequence	Partly random	`BL7E614A0RH68001`
snowflake	unirand.uid('snowflake').random()	5 bytes timestamp, 28 bit machine id (random payload in browser), 12 bit increased (with any call) sequence	Non random, Partly random in browser	`20803747841385512962`
sonyflake	unirand.uid('sonyflake').random()	5 bytes of time (10 ms) + 1 byte sequence (increased with any call) + 2 bytes machine id (random in browser)	Non random, Partly random in browser	`04814e6d06001a954`
ulid	unirand.uid('ulid').random()	6 bytes of time (milliseconds) + 8 bytes random	Partly random	`05TKQ54NHR33S59T4ABCJGR`
xid	unirand.uid('xid').random()	4 bytes of time (seconds) + 3 byte machine id + 2 byte process id + 3 bytes random	Partly random	`1GCU16S2L5A7824LPPHG`

It supports unirand.uid(<type>).next() method as well, but it will not have much effect as all UID generators are not fully random.

k-fold

Splits array into k subarrays. Requires at least 2 arguments: array itself and k. Also supports options.

type: output type, list (default) for output like [<fold>, <fold>, <fold>, ...], set for output like {0: <fold>, 1: <fold>, 2: <fold>, ...}, crossvalidation for output like [{test: <fold>, data: <remaining folds>}, ...]
derange: items will be shuffled as random permutation (default, derange: false) or random derangement (derange: true)

const kfold = unirand.kfold;
kfold([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 3); // [ [ 9, 8, 2, 10 ], [ 1, 7, 3 ], [ 4, 5, 6 ] ]

// with options
kfold([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 3, {
    type: 'set',
    derange: true
});
// { '0': [ 8, 10, 7, 1 ], '1': [ 6, 4, 9 ], '2': [ 5, 2, 3 ] }

// cross validation
kfold([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 3, {
    type: 'crossvalidation',
    derange: true
})
// [ { id: 0, test: [ 5, 6, 9, 7 ], data: [ 4, 1, 10, 2, 8, 3 ] },
//  { id: 1, test: [ 4, 1, 10 ], data: [ 5, 6, 9, 7, 2, 8, 3 ] },
//  { id: 2, test: [ 2, 8, 3 ], data: [ 5, 6, 9, 7, 4, 1, 10 ] } ]

For permutation unirand uses seeded PRNG. With seed k-fold will always return same result.

Does not mutate input!

Smooth data

Smooth method return an array contains smoothed data using different algorithms and strategies for smoothing.

const asyncSmoothedData = await unirand.smooth(data: Array<number>, ?options); // Asynchronous smoothing
const syncSmoothedData = unirand.smoothSync(data: Array<number>, ?options); // Synchronous smoothing

// method return Array<number> of smoothed data
// @example
// for data [2, 6, 9, 4, 6, 7, 3, 2, 4, 7] .smooth method will return [4.375, 5, 5.75, 6.375, 5.75, 4.75, 4.25, 4, 4.5, 5.25]

You can also specify options for smoothing. Multiple options are allowed:

Policy or pre-defined algorithm

Unirand provides different well known pre-defined algorithms (default - 2x4-MA) You can choose for smoothing:

const smoothedData = unirand.smoothSync(data, {
    policy: '2x4-MA' // will implement 4-MA followed by 2-MA algorithm for smoothing
});

Allowed policies:

3-MA - centered moving average of 3th order
5-MA - centered moving average of 5th order
2x4-MA - 4-MA followed by 2-MA
2x8-MA - 8-MA followed by 2-MA
2x12-MA - 12-MA followed by 2-MA
3x3-MA - 3-MA followed by 3-MA
3x5-MA - 5-MA followed by 3-MA
H5-MA - Henderson’s weighted moving average
H9-MA - Henderson’s weighted moving average
H13-MA - Henderson’s weighted moving average
H23-MA - Henderson’s weighted moving average
S15-MA - Spencer’s weighted moving average
S21-MA - Spencer’s weighted moving average

Custom weights

Instead of policy You can specify Your own custom weights:

const smoothedData = unirand.smoothSync(data, {
    weights: [0.1, 0.2, 0.3, 0.4] // will be treated as [0.1, 0.2, 0, 0.3, 0.4]
});
// or
const smoothedData = unirand.smoothSync(data, {
    weights: [0.1, 0.2, 0.3, 0.2, 0.2]
});
// Important: sum of weights must be equal to 1
// will return centered weighted moving average

If You want to get non-centered moving average You can point centerIndex option. Without centerIndex option unirand will treated weights as centered weights.

const smoothedData = unirand.smoothSync(data, {
    weights: [0.1, 0.2, 0.3, 0.4],
    centerIndex: 3 // must be 0 <= centerIndex < weights.length
});

Custom order

You can point moving average order. Unirand will calculate m-ordered moving average.

const smoothedData = unirand.smoothSync(data, {
    order: 5 // will calculate moving average for five point including current one,  (y[i-2] + y[i-1] + y[i] + y[i+1] + y[i+2]) / 5
});
// for even orders
const smoothedData = unirand.smoothSync(data, {
    order: 4 // (y[i-2] + y[i-1] + y[i] + y[i+1]) / 4
});
// or if You want centered moving average
const smoothedData = unirand.smoothSync(data, {
    order: 4,
    centered: true // (y[i-2] + y[i-1] + y[i+1] + y[i+2]) / 4
});

Analize diff

Unirand allow You to get diff between real and smoothed data (allowed for other all possible options). Unirand will return smoothed data, diff and result of diff analysis:

const smoothedData = unirand.smoothSync(data, {
    diff: true
});
// or
const smoothedData = unirand.smoothSync(data, {
    policy: '2x4-MA',
    diff: true
});
// or
const smoothedData = unirand.smoothSync(data, {
    weights: [0.1, 0.2, 0.3, 0.4],
    centerIndex: 3,
    diff: true
});
// or
const smoothedData = unirand.smoothSync(data, {
    order: 4,
    centered: true,
    diff: true
});
// for example data: 
const data = [2, 6, 9, 4, 6, 7, 3, 2, 4, 7];
// unirand will return
{ 
    smoothData: [ 4.375, 5, 5.75, 6.375, 5.75, 4.75, 4.25, 4, 4.5, 5.25 ],
    diff: { 
        diffData: [ -2.375, 1, 3.25, -2.375, 0.25, 2.25, -1.25, -2, -0.5, 1.75 ],
        min: -2.375,
        max: 3.25,
        mean: 3.552713678800501e-17,
        mode: [ -2.375 ],
        variance: 4.09375,
        standard_deviation: 2.023301757029831,
        entropy: 1.8495713674278502,
        skewness: 0.21525076336911947,
        kurtosis: 1.692241451870844,
        pdf: { values: [Array], probabilities: [Array] },
        cdf: { values: [Array], probabilities: [Array] },
        quartiles: { q1: -2.09375, q2: -0.125, q3: 1.1875 },
        median: -0.125,
        interquartile_range: 3.28125
    }
}

By default diff option is false. Does not mutate original array.

Hash

Returns hash using murmur3 algorithm

unirand.hash('unirand'); // string input
// or
unirand.hash(123456); // numerical input

Also supports different seed values. By default, seed value is zero.

unirand.hash('unirand', 123);

Seed can be array, meaning that .hash returns array of hash values for different seeds:

unirand.hash('unirand', [1, 2, 3, 4]); // output [<hash1>, <hash2>, <hash3>, <hash4>]

Also supports different hash algorithms:

Murmur3 - unirand.hash('unirand', 0, {algorithm: 'murmur'})
Jenkins - unirand.hash('unirand', 0, {algorithm: 'jenkins'})

Alternate usage:

unirand.hash('unirand', {
    algorithm: 'murmur'
});
// or
unirand.hash('unirand', 123, {
    algorithm: 'jenkins'
});
// or
unirand.hash('unirand', [1, 2, 3], {
    algorithm: 'murmur'
}); // outputs array of hash values

If You want to bound hash values, You can use option modulo (0x080000000 by default):

unirand.hash('unirand', 123, {
    algorithm: 'jenkins',
    modulo: 1234
});
// or
unirand.hash('unirand', 123, {
    modulo: 1234
}); // will use murmur3 algorithm as default value

Winsorize

Winsorization replaces extreme data values with less extreme values. Winsorization is the transformation of statistics by limiting extreme values in the statistical data to reduce the effect of possibly spurious outliers. Parameters:

input: array of numbers
limits: single number, represent same value trimming value from left and right (should be 0 < limit < 0.5), or an array [left trim value, right trim value] (values should be 0 < left trim value < right trim value < 1)
mutate: <true|false> value (default true). If true - mutate original array, otherwise - no

const winsorize = unirand.winsorize;
winsorize(input: <array>, limits: <number|array>, mutate: <true|false>);
const input = [92, 19, 101, 58, 1053, 91, 26, 78, 10, 13, −40, 101, 86, 85, 15, 89, 89, 28, −5, 41];
winsorize(input, 0.05, false); // returns [92, 19, 101, 58, 101, 91, 26, 78, 10, 13, −5, 101, 86, 85, 15, 89, 89, 28, −5, 41]
// replaced -40 with -5 and 1053 with 101

Utils

Different utils (Special functions list)

unirand.utils.gamma(2); // returns gamma function with argument 2
unirand.utils.digamma(2); // returns digamma function with argument 2
unirand.utils.erf(2); // returns error function with argument 2

Encoder

You can also encode and decode strings with well known encoders:

unirand.encoder(<type>).encode(<string to encode>);
unirand.encoder(<type>).encodeFromByteArray(<byte array to encode>);
unirand.encoder(<type>).decode(<string to decode>);
unirand.encoder(<type>).decodeToByteArray(<string to decode>);

Allowed types:

base62
base64
base32
base32Hex
z-base-32
crockford-base32
base58
bitcoin-base58
flickr-base58
ripple-base58

RandomColor

This method generates a random color with good contrast and randomness:

const randomColor = unirand.randomColor(<saturation value>); // 0 <= saturation <= 1
console.log(randomColor); // will return #f8b34a

// You can specify two types of returned result, 'rgb' and 'hex' (default)
unirand.randomColor(0.9, 'hex'); // #b97437
unirand.randomColor(0.9, 'rgb'); // [54, 181, 116]

// for seeded generator supports also nextColor method
unirand.seed('unirand');
unirand.randomColor(0.9, 'hex'); // #132ac5
unirand.randomColor(0.9, 'hex'); // #132ac5
unirand.nextColor(0.9, 'hex'); // #9dc413
unirand.nextColor(0.9, 'hex'); // #7f16e0

// You are able to generate random vector as well
unirand.randomColor(0.9, 'hex', 5); // ['#23bf13', '#6bcc14', '#dc5a16', '#14cd5d', '#6a15d3']
unirand.randomColor(0.9, 'rgb', 3); // [[ 203, 116, 20 ], [ 23, 236, 61 ], [ 45, 23, 232 ]]

Chance

Chance returns true with given probability

const chance = unirand.chance;
chance(0.3); // returns true with 30% probability

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Readme.md

Readme.md

Unirand

Supported distributions

Installation and Usage

PRNG

.random(), .randomInt() and .randomInRange(from, to)

.next(), .nextInt() and .nextInRange(from, to)

.seed()

PRNG Factory

Random number

Random distribution

Analyze

Sample

Shuffle

Derange

Roulette wheel

String utils

UID generation

k-fold

Smooth data

Policy or pre-defined algorithm

Custom weights

Custom order

Analize diff

Hash

Winsorize

Utils

Encoder

RandomColor

Chance

Files

Readme.md

Latest commit

History

Readme.md

File metadata and controls

Unirand

Supported distributions

Installation and Usage

PRNG

.random(), .randomInt() and .randomInRange(from, to)

.next(), .nextInt() and .nextInRange(from, to)

.seed()

PRNG Factory

Random number

Random distribution

Analyze

Sample

Shuffle

Derange

Roulette wheel

String utils

UID generation

k-fold

Smooth data

Policy or pre-defined algorithm

Custom weights

Custom order

Analize diff

Hash

Winsorize

Utils

Encoder

RandomColor

Chance