diff options
Diffstat (limited to '')
| -rw-r--r-- | stdlib/source/lux/math/random.lux | 49 |
1 files changed, 37 insertions, 12 deletions
diff --git a/stdlib/source/lux/math/random.lux b/stdlib/source/lux/math/random.lux index 44bded416..bb2362d62 100644 --- a/stdlib/source/lux/math/random.lux +++ b/stdlib/source/lux/math/random.lux @@ -250,8 +250,8 @@ (wrap (<plus> x xs))) (\ ..monad wrap <zero>)))] - [list List (.list) #.Cons] - [row Row row.empty row.add] + [list List (.list) #.Cons] + [row Row row.empty row.add] ) (template [<name> <type> <ctor>] @@ -338,21 +338,27 @@ (All [a] (-> PRNG (Random a) [PRNG a])) (calc prng)) -(def: pcg-32-magic Nat 6364136223846793005) +(def: #export (prng update return) + (All [a] (-> (-> a a) (-> a I64) (-> a PRNG))) + (function (recur state) + (function (_ _) + [(recur (update state)) + (return state)]))) (def: #export (pcg-32 [increase seed]) {#.doc (doc "An implementation of the PCG32 algorithm." "For more information, please see: http://www.pcg-random.org/")} (-> [(I64 Any) (I64 Any)] PRNG) - (function (_ _) - [(|> seed .nat (n.* ..pcg-32-magic) ("lux i64 +" increase) [increase] pcg-32) - (let [rot (|> seed .i64 (i64.logic-right-shift 59))] - (|> seed - (i64.logic-right-shift 18) - (i64.xor seed) - (i64.logic-right-shift 27) - (i64.rotate-right rot) - .i64))])) + (let [magic 6364136223846793005] + (function (_ _) + [(|> seed .nat (n.* magic) ("lux i64 +" increase) [increase] pcg-32) + (let [rot (|> seed .i64 (i64.logic-right-shift 59))] + (|> seed + (i64.logic-right-shift 18) + (i64.xor seed) + (i64.logic-right-shift 27) + (i64.rotate-right rot) + .i64))]))) (def: #export (xoroshiro-128+ [s0 s1]) {#.doc (doc "An implementation of the Xoroshiro128+ algorithm." @@ -366,3 +372,22 @@ (i64.xor (i64.left-shift 14 s01))) (i64.rotate-left 36 s01)])) ("lux i64 +" s0 s1)])) + +## https://en.wikipedia.org/wiki/Xorshift#Initialization +## http://xorshift.di.unimi.it/splitmix64.c +(def: #export split-mix-64 + {#.doc (doc "An implementation of the SplitMix64 algorithm.")} + (-> Nat PRNG) + (let [twist (: (-> Nat Nat Nat) + (function (_ shift value) + (i64.xor (i64.logic-right-shift shift value) value))) + mix n.*] + (..prng (n.+ (hex "9E,37,79,B9,7F,4A,7C,15")) + (|>> (twist 30) + (mix (hex "BF,58,47,6D,1C,E4,E5,B9")) + + (twist 27) + (mix (hex "94,D0,49,BB,13,31,11,EB")) + + (twist 31) + .i64)))) |