Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 | 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x | /**
* @license Apache-2.0
*
* Copyright (c) 2025 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
'use strict';
// MODULES //
var factory = require( './factory.js' );
var randuint32 = require( './rand_uint32.js' );
// MAIN //
/**
* Generates a pseudorandom integer on the interval \\( [1,2^{32}-1) \\).
*
* ## Method
*
* Xorshift generators are a class of shift-register PRNGs that generate the next state by applying a sequence of bitwise XOR and shift operations, avoiding the use of multiplication or division.
*
* ```c
* state ^= state << a;
* state ^= state >> b;
* state ^= state << c;
* ```
*
* where \\( state \\) is a positive integer and \\( a, b, c \\) are carefully chosen shift constants.
*
* <!-- <note> -->
*
* In this implementation for 32-bit unsigned integers, the constants are:
*
* ```tex
* \begin{align*}
* a &= 13 \\
* b &= 17 \\
* c &= 5
* \end{align*}
* ```
*
* <!-- </note> -->
*
* The chosen parameters ensure a full-period generator, meaning it cycles through all nonzero 32-bit unsigned values before repeating.
*
* <!-- <note> -->
*
* Unlike linear congruential generators (LCGs), xorshift PRNGs do not rely on modular arithmetic, making them faster in software but requiring careful parameter selection to maintain statistical properties.
*
* <!-- </note> -->
*
* ## Notes
*
* - Xorshift PRNGs are extremely fast but may fail some statistical tests if not combined with additional non-linear operations.
* - This implementation follows the basic xorshift32 algorithm introduced by George Marsaglia.
*
* ## References
*
* - Marsaglia, G. 2003. "Xorshift RNGs." _Journal of Statistical Software_ 8 (14). Los Angeles, CA, USA: American Statistical Association: 1–6. doi:[10.18637/jss.v008.i14](https://doi.org/10.18637/jss.v008.i14).
*
* @function xorshift
* @type {PRNG}
* @returns {PositiveInteger} pseudorandom integer
*
* @example
* var v = xorshift32();
* // returns <number>
*/
var xorshift32 = factory({
'seed': randuint32()
});
// EXPORTS //
module.exports = xorshift32;
|