Pseudo-random numbers/PCG32: Difference between revisions

<lang lua>function uint32(n)

return n & 0xffffffff

end

function uint64(n)

return n & 0xffffffffffffffff

end

N = 6364136223846793005

state = 0x853c49e6748fea9b

inc = 0xda3e39cb94b95bdb

function pcg32_seed(seed_state, seed_sequence)

state = 0

inc = (seed_sequence << 1) | 1

pcg32_int()

state = state + seed_state

pcg32_int()

end

function pcg32_int()

local old = state

state = uint64(old * N + inc)

local shifted = uint32(((old >> 18) ~ old) >> 27)

local rot = uint32(old >> 59)

return uint32((shifted >> rot) | (shifted << ((~rot + 1) & 31)))

end

function pcg32_float()

return 1.0 * pcg32_int() / (1 << 32)

end

-------------------------------------------------------------------

pcg32_seed(42, 54)

print(pcg32_int())

print(pcg32_int())

print(pcg32_int())

print(pcg32_int())

print(pcg32_int())

print()

counts = { 0, 0, 0, 0, 0 }

pcg32_seed(987654321, 1)

for i=1,100000 do

local j = math.floor(pcg32_float() * 5.0) + 1

counts[j] = counts[j] + 1

end

print("The counts for 100,000 repetitions are:")

for i=1,5 do

print(" " .. (i - 1) .. ": " .. counts[i])

end</lang>