Dev prng factory (#20)

* newPrng method added In order to support independent PRNG creation new method added. It supports all PRNG types, as well as seed. Some PRNG bugs fixed. * Default PRNG type changed to taus113 * Tests refactored Co-authored-by: Alexey Kiselev <[email protected]>
AlexeySKiselev · Jul 4, 2021 · ebe41d6 · ebe41d6
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diff --git a/Readme.md b/Readme.md
@@ -130,6 +130,26 @@ 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.
+
+```javascript
+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*:
 ```javascript

diff --git a/core/prng/Dx1597PRNG.js b/core/prng/Dx1597PRNG.js
@@ -149,6 +149,7 @@ class Dx1597PRNG extends BasicPRNG implements IPRNG {
             this._no_seed = false;
         } else if (typeof seed_value === 'string') {
             this._seed = seed_value;
+            this._pointer = 0;
             for (let i = 0; i < this._seed.length; i += 1) {
                 this._pointer = (this._pointer + this._seed.charCodeAt(i)) % WORD_4;
             }

diff --git a/core/prng/Gfsr4PRNG.js b/core/prng/Gfsr4PRNG.js
@@ -133,6 +133,7 @@ class Gfsr4PRNG extends BasicPRNG implements IPRNG {
             this._no_seed = false;
         } else if (typeof seed_value === 'string') {
             this._seed = seed_value;
+            this._pointer = 0;
             for (let i = 0; i < this._seed.length; i += 1) {
                 this._pointer = (this._pointer + this._seed.charCodeAt(i)) % WORD_D;
             }

diff --git a/core/prng/MarsenneTwisterPRNG.js b/core/prng/MarsenneTwisterPRNG.js
@@ -124,6 +124,7 @@ class MarsenneTwisterPRNG extends BasicPRNG implements IPRNG {
             this._no_seed = false;
         } else if (typeof seed_value === 'string') {
             this._seed = seed_value;
+            this._pointer = 0;
             for (let i = 0; i < this._seed.length; i += 1) {
                 this._pointer = (this._pointer + this._seed.charCodeAt(i)) % WORD_LEFT;
             }

diff --git a/core/prng/Mrg5PRNG.js b/core/prng/Mrg5PRNG.js
@@ -161,6 +161,7 @@ class Mrg5PRNG extends BasicPRNG implements IPRNG {
             this._no_seed = false;
         } else if (typeof seed_value === 'string') {
             this._seed = seed_value;
+            this._pointer = 0;
             for (let i = 0; i < this._seed.length; i += 1) {
                 this._pointer = (this._pointer + this._seed.charCodeAt(i)) % WORD_LEFT;
             }

diff --git a/core/prng/R250PRNG.js b/core/prng/R250PRNG.js
@@ -124,6 +124,7 @@ class R250PRNG extends BasicPRNG implements IPRNG {
             this._no_seed = false;
         } else if (typeof seed_value === 'string') {
             this._seed = seed_value;
+            this._pointer = 0;
             for (let i = 0; i < this._seed.length; i += 1) {
                 this._pointer = (this._pointer + this._seed.charCodeAt(i)) % WORD_LEFT;
             }

diff --git a/core/prng/Swb2712PRNG.js b/core/prng/Swb2712PRNG.js
@@ -132,6 +132,7 @@ class Swb2712PRNG extends BasicPRNG implements IPRNG {
             this._no_seed = false;
         } else if (typeof seed_value === 'string') {
             this._seed = seed_value;
+            this._pointer = 0;
             for (let i = 0; i < this._seed.length; i += 1) {
                 this._pointer = (this._pointer + this._seed.charCodeAt(i)) % LAG_R;
             }

diff --git a/core/prng/prngProxy.js b/core/prng/prngProxy.js
@@ -27,7 +27,7 @@ import PhiloxPRNG from './PhiloxPRNG';
 import Taus113PRNG from './Taus113PRNG';
 import Swb2712PRNG from './Swb2712PRNG';
 
-const DEFAULT_GENERATOR = 'tuchei';
+const DEFAULT_GENERATOR: string = 'taus113';
 
 class PRNGProxy implements IPRNGProxy {
 

diff --git a/index.js b/index.js
@@ -11,7 +11,7 @@ import Winsorize from './core/array_manipulation/winsorize';
 import KFold from './core/array_manipulation/kfold';
 import hashProxy from './core/utils/hash';
 import smoothProxy from './core/array_manipulation/smooth';
-import prngProxy from './core/prng/prngProxy';
+import prngProxy, { PRNGProxy } from './core/prng/prngProxy';
 import encoderProxy from './core/utils/encoders/encoderProxy';
 import UidFactory from './core/uidFactory';
 import {DEFAULT_GENERATOR} from './core/prng/prngProxy';
@@ -60,6 +60,7 @@ class RandomJS {
     smooth: ISmooth;
     smoothSync: ISmooth;
     newRouletteWheel: IRouletteWheel;
+    newPrng: IPRNGProxy;
     _randomColorFabric: IRandomColor;
     randomColor: any;
     nextColor: any;
@@ -289,6 +290,19 @@ class RandomJS {
             }
         }: Object));
 
+        /**
+         * Factory produces new PRNGs
+         */
+        Object.defineProperty(this, 'newPrng', ({
+            __proto__: null,
+            value: (name: string, seed: any = undefined): IPRNGProxy => {
+                const _prngProxy: IPRNGProxy = new PRNGProxy();
+                _prngProxy.seed(seed);
+                _prngProxy.set_prng(name);
+                return _prngProxy;
+            }
+        }: Object));
+
         /**
          * PRNG seed
          */
@@ -421,6 +435,7 @@ const methods = {
     randomInRange: randomjs.randomInRange,
     nextInRange: randomjs.nextInRange,
     newRouletteWheel: randomjs.newRouletteWheel,
+    newPrng: randomjs.newPrng,
     randomColor: randomjs.randomColor,
     nextColor: randomjs.nextColor
 };

diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "unirand",
-  "version": "2.12.0",
+  "version": "2.12.2",
   "description": "Random numbers and Distributions generation",
   "main": "./lib/index.js",
   "scripts": {

diff --git a/test/index.test.js b/test/index.test.js
@@ -11,7 +11,7 @@ chai.should();
 
 const methods = ['analyze', 'utils', 'stringutils', 'sample', 'kfold', 'shuffle', 'derange', 'chance', 'winsorize',
     'hash', 'smooth', 'smoothSync', 'seed', 'random', 'next', 'randomInt', 'nextInt',
-    'randomInRange', 'nextInRange', 'newRouletteWheel', 'randomColor', 'nextColor', 'encoder', 'uid']; // check prng separately
+    'randomInRange', 'nextInRange', 'newRouletteWheel', 'newPrng', 'randomColor', 'nextColor', 'encoder', 'uid']; // check prng separately
 
 describe('Index', () => {
     it('unirand should have all supported methods', () => {

diff --git a/test/prng.test.js b/test/prng.test.js
@@ -6,7 +6,8 @@
 let chai = require('chai'),
     expect = chai.expect,
     {describe, it} = require('mocha'),
-    prng = require('../lib/prng/prngProxy').default;
+    prng = require('../lib/prng/prngProxy').default,
+    newPrng = require('../lib').newPrng;
 
 chai.should();
 
@@ -216,6 +217,59 @@ describe('PRNGProxy', () => {
     });
 });
 
+describe('newPrng', () => {
+    it('should support .random(), .randomInt(), .next(), .nextInt(), .seed() methods', () => {
+        const prng = newPrng('tt800', 12345);
+        expect(prng).to.have.property('random');
+        expect(prng).to.respondsTo('random');
+
+        expect(prng).to.have.property('randomInt');
+        expect(prng).to.respondsTo('randomInt');
+
+        expect(prng).to.have.property('next');
+        expect(prng).to.respondsTo('next');
+
+        expect(prng).to.have.property('nextInt');
+        expect(prng).to.respondsTo('nextInt');
+
+        expect(prng).to.have.property('seed');
+        expect(prng).to.respondsTo('seed');
+    });
+    it('should support all allowed generators', () => {
+        const prng = newPrng('default');
+        const generators = prng.generators;
+
+        for (let generator of generators) {
+            let goodPrng = () => {
+                return newPrng(generator);
+            };
+            goodPrng.should.not.throw(Error);
+        }
+    });
+    it('should throw an error for unsupported generator', () => {
+        let badPrng = () => {
+            return newPrng('abc');
+        };
+        badPrng.should.throw(Error);
+    });
+    it('should support seed', () => {
+        const prng = newPrng('tt800', 'unirand');
+        expect(prng.random()).to.be.closeTo(prng.random(), 0.00001);
+
+        const prngNoSeed = newPrng('tt800');
+        expect(Math.abs(prngNoSeed.random() - prngNoSeed.random()) > 0.00001).to.be.equal(true);
+    });
+    it('should be independent', () => {
+        const prng1 = newPrng('tt800', 'unirand');
+        const prng2 = newPrng('tt800', 'random seed');
+        const prng3 = newPrng('r250', 'unirand');
+
+        expect(Math.abs(prng1.random() - prng2.random()) > 0.00001).to.be.equal(true);
+        expect(Math.abs(prng2.random() - prng3.random()) > 0.00001).to.be.equal(true);
+        expect(Math.abs(prng1.random() - prng3.random()) > 0.00001).to.be.equal(true);
+    });
+});
+
 describe('tuchei PRNG', () =>  {
     prngTest('tuchei');
 });

diff --git a/test/stringutils.test.js b/test/stringutils.test.js
@@ -93,7 +93,7 @@ describe('String Utils', () => {
             let randomString;
             const alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
             for (let i = 0; i < 10000; i += 1) {
-                randomString = StringUtils.random(alphabet, 100);
+                randomString = StringUtils.random(alphabet, 200);
                 randomStrings[randomString] = 1;
             }
             expect(Object.keys(randomStrings).length).to.be.equal(10000);
@@ -157,7 +157,7 @@ describe('String Utils', () => {
             const randomStrings = {};
             let randomString;
             for (let i = 0; i < 10000; i += 1) {
-                randomString = StringUtils.randomAlphabetic(100);
+                randomString = StringUtils.randomAlphabetic(200);
                 randomStrings[randomString] = 1;
             }
             expect(Object.keys(randomStrings).length).to.be.equal(10000);
@@ -220,7 +220,7 @@ describe('String Utils', () => {
             const randomStrings = {};
             let randomString;
             for (let i = 0; i < 10000; i += 1) {
-                randomString = StringUtils.randomAscii(100);
+                randomString = StringUtils.randomAscii(200);
                 randomStrings[randomString] = 1;
             }
             expect(Object.keys(randomStrings).length).to.be.equal(10000);
@@ -283,7 +283,7 @@ describe('String Utils', () => {
             const randomStrings = {};
             let randomString;
             for (let i = 0; i < 10000; i += 1) {
-                randomString = StringUtils.randomAlphanumeric(100);
+                randomString = StringUtils.randomAlphanumeric(200);
                 randomStrings[randomString] = 1;
             }
             expect(Object.keys(randomStrings).length).to.be.equal(10000);
@@ -346,7 +346,7 @@ describe('String Utils', () => {
             const randomStrings = {};
             let randomString;
             for (let i = 0; i < 10000; i += 1) {
-                randomString = StringUtils.randomNumeric(100);
+                randomString = StringUtils.randomNumeric(200);
                 randomStrings[randomString] = 1;
             }
             expect(Object.keys(randomStrings).length).to.be.equal(10000);
@@ -409,7 +409,7 @@ describe('String Utils', () => {
             const randomStrings = {};
             let randomString;
             for (let i = 0; i < 10000; i += 1) {
-                randomString = StringUtils.randomHex(100);
+                randomString = StringUtils.randomHex(200);
                 randomStrings[randomString] = 1;
             }
             expect(Object.keys(randomStrings).length).to.be.equal(10000);