stdlib-js
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MINSTD Shuffle
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
A linear congruential pseudorandom number generator ([LCG][lcg]) whose output is shuffled.
bash
npm install @stdlib/random-base-minstd-shuffle
javascript
var minstd = require( '@stdlib/random-base-minstd-shuffle' );
#### minstd()
Returns a pseudorandom integer on the interval [1, 2147483646].
javascript
var v = minstd();
// returns <number>
#### minstd.normalized()
Returns a pseudorandom number on the interval [0,1).
javascript
var v = minstd.normalized();
// returns <number>
#### minstd.factory( [options] )
Returns a linear congruential pseudorandom number generator ([LCG][lcg]) whose output is shuffled.
javascript
var rand = minstd.factory();
The function accepts the following options:
- seed: pseudorandom number generator seed.
- state: an [Int32Array][@stdlib/array/int32] containing pseudorandom number generator state. If provided, the function ignores the seed option.
- copy: boolean indicating whether to copy a provided pseudorandom number generator state. Setting this option to false allows sharing state between two or more pseudorandom number generators. Setting this option to true ensures that a returned generator has exclusive control over its internal state. Default: true.
By default, a random integer is used to seed the returned generator. To seed the generator, provide either an integer on the interval [1, 2147483646]
javascript
var rand = minstd.factory({
'seed': 1234
});
var v = rand();
// returns 1421600654
or, for arbitrary length seeds, an array-like object containing signed 32-bit integers
javascript
var Int32Array = require( '@stdlib/array-int32' );
var rand = minstd.factory({
'seed': new Int32Array( [ 1234 ] )
});
var r = rand();
// returns 20739838
To return a generator having a specific initial state, set the generator state option.
javascript
var rand;
var bool;
var r;
var i;
// Generate pseudorandom numbers, thus progressing the generator state:
for ( i = 0; i < 1000; i++ ) {
r = minstd();
}
// Create a new PRNG initialized to the current state of `minstd`:
rand = minstd.factory({
'state': minstd.state
});
// Test that the generated pseudorandom numbers are the same:
bool = ( rand() === minstd() );
// returns true
#### minstd.NAME
The generator name.
javascript
var str = minstd.NAME;
// returns 'minstd-shuffle'
#### minstd.MIN
Minimum possible value.
javascript
var min = minstd.MIN;
// returns 1
#### minstd.MAX
Maximum possible value.
javascript
var max = minstd.MAX;
// returns 2147483646
#### minstd.seed
The value used to seed minstd().
javascript
var rand;
var v;
var i;
// Generate pseudorandom values...
for ( i = 0; i < 100; i++ ) {
v = minstd();
}
// Generate the same pseudorandom values...
rand = minstd.factory({
'seed': minstd.seed
});
for ( i = 0; i < 100; i++ ) {
v = rand();
}
#### minstd.seedLength
Length of generator seed.
javascript
var len = minstd.seedLength;
// returns <number>
#### minstd.state
Writable property for getting and setting the generator state.
javascript
var r = minstd();
// returns <number>
r = minstd();
// returns <number>
// ...
// Get a copy of the current state:
var state = minstd.state;
// returns <Int32Array>
r = minstd();
// returns <number>
r = minstd();
// returns <number>
// Reset the state:
minstd.state = state;
// Replay the last two pseudorandom numbers:
r = minstd();
// returns <number>
r = minstd();
// returns <number>
// ...
#### minstd.stateLength
Length of generator state.
javascript
var len = minstd.stateLength;
// returns <number>
#### minstd.byteLength
Size (in bytes) of generator state.
javascript
var sz = minstd.byteLength;
// returns <number>
#### minstd.toJSON()
Serializes the pseudorandom number generator as a JSON object.
javascript
var o = minstd.toJSON();
// returns { 'type': 'PRNG', 'name': '...', 'state': {...}, 'params': [] }
2.1e9 (see Numerical Recipes in C, 2nd Edition, p. 279).
- An [LCG][lcg] is fast and uses little memory. On the other hand, because the generator is a simple [linear congruential generator][lcg], the generator has recognized shortcomings. By today's PRNG standards, the generator's period is relatively short. In general, this generator is unsuitable for Monte Carlo simulations and cryptographic applications.
- If PRNG state is "shared" (meaning a state array was provided during PRNG creation and not copied) and one sets the generator state to a state array having a different length, the PRNG does not update the existing shared state and, instead, points to the newly provided state array. In order to synchronize PRNG output according to the new shared state array, the state array for each relevant PRNG must be explicitly set.
- If PRNG state is "shared" and one sets the generator state to a state array of the same length, the PRNG state is updated (along with the state of all other PRNGs sharing the PRNG's state array).
javascript
var minstd = require( '@stdlib/random-base-minstd-shuffle' );
var seed;
var rand;
var i;
// Generate pseudorandom numbers...
for ( i = 0; i < 100; i++ ) {
console.log( minstd() );
}
// Create a new pseudorandom number generator...
seed = 1234;
rand = minstd.factory({
'seed': seed
});
for ( i = 0; i < 100; i++ ) {
console.log( rand() );
}
// Create another pseudorandom number generator using a previous seed...
rand = minstd.factory({
'seed': minstd.seed
});
for ( i = 0; i < 100; i++ ) {
console.log( rand() );
}
@stdlib/random-base/minstd][@stdlib/random/base/minstd]: A linear congruential pseudorandom number generator (LCG) based on Park and Miller.
- [@stdlib/random-base/mt19937][@stdlib/random/base/mt19937]: A 32-bit Mersenne Twister pseudorandom number generator.
- [@stdlib/random-base/randi][@stdlib/random/base/randi]: pseudorandom numbers having integer values.
