diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/pure/random.nim | 93 |
1 files changed, 36 insertions, 57 deletions
diff --git a/lib/pure/random.nim b/lib/pure/random.nim index e58623baa..6a5f35bde 100644 --- a/lib/pure/random.nim +++ b/lib/pure/random.nim @@ -133,11 +133,10 @@ proc next*(r: var Rand): uint64 = ## that accepts a slice ## * `rand proc<#rand,typedesc[T]>`_ that accepts an integer or range type ## * `skipRandomNumbers proc<#skipRandomNumbers,Rand>`_ - runnableExamples: + runnableExamples("-r:off"): var r = initRand(2019) - doAssert r.next() == 138_744_656_611_299'u64 - doAssert r.next() == 979_810_537_855_049_344'u64 - doAssert r.next() == 3_628_232_584_225_300_704'u64 + assert r.next() == 13223559681708962501'u64 # implementation defined + assert r.next() == 7229677234260823147'u64 # ditto let s0 = r.a0 var s1 = r.a1 @@ -214,11 +213,9 @@ proc rand*(r: var Rand; max: Natural): int {.benign.} = ## * `rand proc<#rand,Rand,HSlice[T: Ordinal or float or float32 or float64,T: Ordinal or float or float32 or float64]>`_ ## that accepts a slice ## * `rand proc<#rand,typedesc[T]>`_ that accepts an integer or range type - runnableExamples: + runnableExamples("-r:off"): var r = initRand(123) - doAssert r.rand(100) == 0 - doAssert r.rand(100) == 96 - doAssert r.rand(100) == 66 + assert r.rand(100) == 96 # implementation defined if max == 0: return while true: @@ -241,11 +238,9 @@ proc rand*(max: int): int {.benign.} = ## * `rand proc<#rand,HSlice[T: Ordinal or float or float32 or float64,T: Ordinal or float or float32 or float64]>`_ ## that accepts a slice ## * `rand proc<#rand,typedesc[T]>`_ that accepts an integer or range type - runnableExamples: + runnableExamples("-r:off"): randomize(123) - doAssert rand(100) == 0 - doAssert rand(100) == 96 - doAssert rand(100) == 66 + assert [rand(100), rand(100)] == [96, 63] # implementation defined rand(state, max) @@ -305,10 +300,8 @@ proc rand*[T: Ordinal or SomeFloat](r: var Rand; x: HSlice[T, T]): T = ## * `rand proc<#rand,typedesc[T]>`_ that accepts an integer or range type runnableExamples: var r = initRand(345) - doAssert r.rand(1..6) == 4 - doAssert r.rand(1..6) == 4 - doAssert r.rand(1..6) == 6 - let f = r.rand(-1.0 .. 1.0) # 0.8741183448756229 + assert r.rand(1..5) <= 5 + assert r.rand(-1.1 .. 1.2) >= -1.1 assert x.a <= x.b when T is SomeFloat: result = rand(r, x.b - x.a) + x.a @@ -333,9 +326,7 @@ proc rand*[T: Ordinal or SomeFloat](x: HSlice[T, T]): T = ## * `rand proc<#rand,typedesc[T]>`_ that accepts an integer or range type runnableExamples: randomize(345) - doAssert rand(1..6) == 4 - doAssert rand(1..6) == 4 - doAssert rand(1..6) == 6 + assert rand(1..6) <= 6 result = rand(state, x) @@ -354,16 +345,12 @@ proc rand*[T: SomeInteger](t: typedesc[T]): T = ## that accepts a slice runnableExamples: randomize(567) - doAssert rand(int8) == 55 - doAssert rand(int8) == -42 - doAssert rand(int8) == 43 - doAssert rand(uint32) == 578980729'u32 - doAssert rand(uint32) == 4052940463'u32 - doAssert rand(uint32) == 2163872389'u32 - doAssert rand(range[1..16]) == 11 - doAssert rand(range[1..16]) == 4 - doAssert rand(range[1..16]) == 16 - + if false: # implementation defined + assert rand(int8) == -42 + assert rand(uint32) == 578980729'u32 + assert rand(range[1..16]) == 11 + # pending csources >= 1.4.0 or fixing https://github.com/timotheecour/Nim/issues/251#issuecomment-831599772, + # use `runnableExamples("-r:off")` instead of `if false` when T is range: result = rand(state, low(T)..high(T)) else: @@ -380,9 +367,7 @@ proc sample*[T](r: var Rand; s: set[T]): T = runnableExamples: var r = initRand(987) let s = {1, 3, 5, 7, 9} - doAssert r.sample(s) == 5 - doAssert r.sample(s) == 7 - doAssert r.sample(s) == 1 + assert r.sample(s) in s assert card(s) != 0 var i = rand(r, card(s) - 1) @@ -406,9 +391,7 @@ proc sample*[T](s: set[T]): T = runnableExamples: randomize(987) let s = {1, 3, 5, 7, 9} - doAssert sample(s) == 5 - doAssert sample(s) == 7 - doAssert sample(s) == 1 + assert sample(s) in s sample(state, s) @@ -423,9 +406,7 @@ proc sample*[T](r: var Rand; a: openArray[T]): T = runnableExamples: let marbles = ["red", "blue", "green", "yellow", "purple"] var r = initRand(456) - doAssert r.sample(marbles) == "blue" - doAssert r.sample(marbles) == "yellow" - doAssert r.sample(marbles) == "red" + assert r.sample(marbles) in marbles result = a[r.rand(a.low..a.high)] @@ -445,9 +426,7 @@ proc sample*[T](a: openArray[T]): T = runnableExamples: let marbles = ["red", "blue", "green", "yellow", "purple"] randomize(456) - doAssert sample(marbles) == "blue" - doAssert sample(marbles) == "yellow" - doAssert sample(marbles) == "red" + assert sample(marbles) in marbles result = a[rand(a.low..a.high)] @@ -476,9 +455,7 @@ proc sample*[T, U](r: var Rand; a: openArray[T]; cdf: openArray[U]): T = let count = [1, 6, 8, 3, 4] let cdf = count.cumsummed var r = initRand(789) - doAssert r.sample(marbles, cdf) == "red" - doAssert r.sample(marbles, cdf) == "green" - doAssert r.sample(marbles, cdf) == "blue" + assert r.sample(marbles, cdf) in marbles assert(cdf.len == a.len) # Two basic sanity checks. assert(float(cdf[^1]) > 0.0) @@ -512,9 +489,7 @@ proc sample*[T, U](a: openArray[T]; cdf: openArray[U]): T = let count = [1, 6, 8, 3, 4] let cdf = count.cumsummed randomize(789) - doAssert sample(marbles, cdf) == "red" - doAssert sample(marbles, cdf) == "green" - doAssert sample(marbles, cdf) == "blue" + assert sample(marbles, cdf) in marbles state.sample(a, cdf) @@ -547,10 +522,10 @@ proc gauss*(mu = 0.0, sigma = 1.0): float {.since: (1, 3).} = proc initRand*(seed: int64): Rand = ## Initializes a new `Rand <#Rand>`_ state using the given seed. ## - ## `seed` must not be zero. Providing a specific seed will produce - ## the same results for that seed each time. + ## Providing a specific seed will produce the same results for that seed each time. ## - ## The resulting state is independent of the default RNG's state. + ## The resulting state is independent of the default RNG's state. When `seed == 0`, + ## we internally set the seed to an implementation defined non-zero value. ## ## **See also:** ## * `initRand proc<#initRand>`_ that uses the current time @@ -560,20 +535,22 @@ proc initRand*(seed: int64): Rand = from std/times import getTime, toUnix, nanosecond var r1 = initRand(123) - let now = getTime() var r2 = initRand(now.toUnix * 1_000_000_000 + now.nanosecond) - - doAssert seed != 0 # 0 causes `rand(int)` to always return 0 for example. + const seedFallback0 = int32.high # arbitrary + let seed = if seed != 0: seed else: seedFallback0 # because 0 is a fixed point result.a0 = Ui(seed shr 16) result.a1 = Ui(seed and 0xffff) + when not defined(nimLegacyRandomInitRand): + # calling `discard next(result)` (even a few times) would still produce + # skewed numbers for the 1st call to `rand()`. + skipRandomNumbers(result) discard next(result) proc randomize*(seed: int64) {.benign.} = ## Initializes the default random number generator with the given seed. ## - ## `seed` must not be zero. Providing a specific seed will produce - ## the same results for that seed each time. + ## Providing a specific seed will produce the same results for that seed each time. ## ## **See also:** ## * `initRand proc<#initRand,int64>`_ that initializes a Rand state @@ -600,7 +577,8 @@ proc shuffle*[T](r: var Rand; x: var openArray[T]) = var cards = ["Ace", "King", "Queen", "Jack", "Ten"] var r = initRand(678) r.shuffle(cards) - doAssert cards == ["King", "Ace", "Queen", "Ten", "Jack"] + import std/algorithm + assert cards.sorted == @["Ace", "Jack", "King", "Queen", "Ten"] for i in countdown(x.high, 1): let j = r.rand(i) @@ -620,7 +598,8 @@ proc shuffle*[T](x: var openArray[T]) = var cards = ["Ace", "King", "Queen", "Jack", "Ten"] randomize(678) shuffle(cards) - doAssert cards == ["King", "Ace", "Queen", "Ten", "Jack"] + import std/algorithm + assert cards.sorted == @["Ace", "Jack", "King", "Queen", "Ten"] shuffle(state, x) |