feature: add XSH_RS, XSH_RR, and RXS_M_XS output functions (#116)

src/__tests__/createPcg32.test.ts

@@ -1,4 +1,5 @@
 import { createPcg32, nextState, prevState, randomInt, randomList } from '..'
+import { OutputFnType } from '../types'
 
 describe('basic', () => {
   it('pCG32_XSH_RR: Single integer', () => {
@@ -11,6 +12,36 @@ describe('basic', () => {
     expect(randomUint32(pcg)[0]).toBe(0xa15c02b7)
   })
 
+  it('pCG32_XSH_RS: Single integer', () => {
+    expect.assertions(2)
+    const randomUint32 = randomInt(0, 2 ** 32 - 1)
+    const pcg = createPcg32({ outputFnType: OutputFnType.XSH_RS }, 42, 54)
+    // Check for generator immutability and result reproducibility
+    const [n, _state] = randomUint32(pcg)
+    expect(n).toBe(1545299392)
+    expect(randomUint32(pcg)[0]).toBe(1545299392)
+  })
+
+  it('pCG32_XSL_RR: Single integer', () => {
+    expect.assertions(2)
+    const randomUint32 = randomInt(0, 2 ** 32 - 1)
+    const pcg = createPcg32({ outputFnType: OutputFnType.XSL_RR }, 42, 54)
+    // Check for generator immutability and result reproducibility
+    const [n, _state] = randomUint32(pcg)
+    expect(n).toBe(110043304)
+    expect(randomUint32(pcg)[0]).toBe(110043304)
+  })
+
+  it('pCG32_RXS_M_XS: Single integer', () => {
+    expect.assertions(2)
+    const randomUint32 = randomInt(0, 2 ** 32 - 1)
+    const pcg = createPcg32({ outputFnType: OutputFnType.RXS_M_XS }, 42, 54)
+    // Check for generator immutability and result reproducibility
+    const [n, _state] = randomUint32(pcg)
+    expect(n).toBe(3562606574)
+    expect(randomUint32(pcg)[0]).toBe(3562606574)
+  })
+
   it('pCG32_XSH_RR: Multiple integers', () => {
     expect.assertions(1)
     const randomUint32 = randomInt(0, 2 ** 32 - 1)
@@ -20,6 +51,33 @@ describe('basic', () => {
     ])
   })
 
+  it('pCG32_XSH_RS: Multiple integers', () => {
+    expect.assertions(1)
+    const randomUint32 = randomInt(0, 2 ** 32 - 1)
+    const pcg = createPcg32({ outputFnType: OutputFnType.XSH_RS }, 42, 54)
+    expect(randomList(6, randomUint32, pcg).map(([value]) => value)).toStrictEqual([
+      1545299392, 2415717169, 3435843701, 3090997190, 1576856010, 3235194092,
+    ])
+  })
+
+  it('pCG32_XSL_RR: Multiple integers', () => {
+    expect.assertions(1)
+    const randomUint32 = randomInt(0, 2 ** 32 - 1)
+    const pcg = createPcg32({ outputFnType: OutputFnType.XSL_RR }, 42, 54)
+    expect(randomList(6, randomUint32, pcg).map(([value]) => value)).toStrictEqual([
+      110043304, 3982559790, 957466950, 3645676572, 223035418, 2465086851,
+    ])
+  })
+
+  it('pCG32_RXS_M_XS: Multiple integers', () => {
+    expect.assertions(1)
+    const randomUint32 = randomInt(0, 2 ** 32 - 1)
+    const pcg = createPcg32({ outputFnType: OutputFnType.RXS_M_XS }, 42, 54)
+    expect(randomList(6, randomUint32, pcg).map(([value]) => value)).toStrictEqual([
+      3562606574, 3701842622, 2826130885, 1212371962, 849807893, 1843984456,
+    ])
+  })
+
   it('pCG32_XSH_RR: Jump-ahead, jump-back', () => {
     expect.assertions(5)
     const randomUint32 = randomInt(0, 2 ** 32 - 1)

src/createPcg.ts

@@ -67,8 +67,8 @@ export const randomInt = curry((min: number, max: number, pcg: PCGState): [numbe
   return [n.mod(bound).add(min).toNumber(), nextPcg]
 })
 
-export const randomList = curry((length, rng, pcg): [number, PCGState][] =>
-  scan(([, nextPcg]) => rng(nextPcg), rng(pcg), new Array(length - 1))
+export const randomList = curry((length, rng, initPcg): [number, PCGState][] =>
+  scan(([, lastPcg]) => rng(lastPcg), rng(initPcg), new Array(length - 1))
 )
 
 export default curry(

src/defaults.ts

@@ -1,15 +1,15 @@
 import Long from 'long'
 import { StreamScheme, OutputFnType } from './types'
 
-// export const pcgDefaultIncrement8 = 77;
-// export const pcgDefaultIncrement16 = 47989;
-// export const pcgDefaultIncrement32 = 2891336453;
-export const pcgDefaultIncrement64 = Long.fromString('1442695040888963407', true)
+// export const pcgDefaultIncrement8 = 77
+// export const pcgDefaultIncrement16 = 47989
+// export const pcgDefaultIncrement32 = Long.fromString('2891336453', 10)
+export const pcgDefaultIncrement64 = Long.fromString('1442695040888963407', 10)
 
-// export const pcgDefaultMultiplier8 = 141;
-// export const pcgDefaultMultiplier16 = 12829;
-// export const pcgDefaultMultiplier32 = 747796405;
-export const pcgDefaultMultiplier64 = Long.fromString('6364136223846793005', true)
+// export const pcgDefaultMultiplier8 = 141
+// export const pcgDefaultMultiplier16 = 12829
+// export const pcgDefaultMultiplier32 = Long.fromString('747796405')
+export const pcgDefaultMultiplier64 = Long.fromString('6364136223846793005', 10)
 
 export const pcgDefaultOutputFnType: OutputFnType = OutputFnType.XSH_RR
 export const pcgDefaultStreamScheme: StreamScheme = StreamScheme.SETSEQ

src/index.ts

@@ -13,5 +13,16 @@ export const createPcg32 = createPcg({
   outputFns: {
     [OutputFnType.XSH_RR]: (state: Long): number =>
       ror32(state.shru(59).toInt(), state.shru(18).xor(state).shru(27).toInt()),
+    [OutputFnType.XSH_RS]: (state: Long): number => state.shru(22).xor(state).shru(state.shru(61).add(22)).toInt(),
+    [OutputFnType.XSL_RR]: (state: Long): number => ror32(state.shru(59).toInt(), state.shru(32).xor(state).toInt()),
+    // [OutputFnType.XSL_RR_RR]: (state: Long): number => {
+    //   const high = state.shru(32)
+    //   const newlow = ror32(state.shru(59).toInt(), high.xor(state).toInt())
+    //   return new Long(ror32(new Long(newlow).and(32).toInt(), high.toInt())).shl(32).or(newlow).toInt()
+    // },
+    [OutputFnType.RXS_M_XS]: (state: Long): number => {
+      const word = state.shru(13).add(3).xor(state).mul(62169)
+      return word.shru(11).xor(word).toInt()
+    },
   },
 })

src/types.ts

@@ -1,13 +1,11 @@
 import Long from 'long'
 
-// TODO: Implement more output functions
-
 export enum OutputFnType {
   XSH_RR = 0,
-  // XSH_RS = 1
-  // XSL_RR = 2
-  // XSL_RR_RR = 3
-  // RXS_M_XS = 4
+  XSH_RS = 1,
+  XSL_RR = 2,
+  // XSL_RR_RR = 3 // currently unstable
+  RXS_M_XS = 4,
 }
 
 export type OutputFn = (state: Long) => number