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crlib: replace random number generator with wyhash.

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Benchmarks shows about 4x increased PRNG perfomance increase comparing to old one. Should slightly reduce per-bot CPU usage.
This commit is contained in:
ds 2020-09-29 19:23:26 +03:00
commit 726ea72965
13 changed files with 189 additions and 179 deletions
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62
ext/crlib/cr-random.h
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@ -20,49 +20,57 @@
CR_NAMESPACE_BEGIN
// random number generator see: https://github.com/preshing/RandomSequence/
class Random final : public Singleton <Random> {
// based on: https://github.com/jeudesprits/PSWyhash/blob/master/Sources/CWyhash/include/wyhash.h
class Random : public Singleton <Random> {
private:
uint32 index_, offset_;
uint64 divider_;
uint64 div_ { static_cast <uint64> (1) << 32ull };
uint64 state_ { static_cast <uint64> (time (nullptr)) };
public:
explicit Random () {
const auto base = static_cast <uint32> (time (nullptr));
const auto offset = base + 1;
index_ = premute (premute (base) + 0x682f0161);
offset_ = premute (premute (offset) + 0x46790905);
divider_ = (static_cast <uint64> (1)) << 32;
}
Random () = default;
~Random () = default;
private:
uint32 premute (uint32 index) {
static constexpr auto prime = 4294967291u;
uint64 wyrand64 () {
constexpr uint64 wyp0 = 0xa0761d6478bd642full, wyp1 = 0xe7037ed1a0b428dbull;
state_ += wyp0;
if (index >= prime) {
return index;
}
const uint32 residue = (static_cast <uint64> (index) * index) % prime;
return (index <= prime / 2) ? residue : prime - residue;
return mul (state_ ^ wyp1, state_);
}
uint32 generate () {
return premute ((premute (index_++) + offset_) ^ 0x5bf03635);
uint32 wyrand32 () {
return static_cast <uint32> (wyrand64 ());
}
private:
uint64_t rotr (uint64 v, uint32 k) {
return (v >> k) | (v << (64 - k));
}
uint64 mul (uint64 a, uint64 b) {
uint64 hh = (a >> 32) * (b >> 32);
uint64 hl = (b >> 32) * static_cast <uint32> (b);
uint64 lh = static_cast <uint32> (a) * (b >> 32);
uint64 ll = static_cast <uint64> (static_cast <double> (a) * static_cast <double> (b));
return rotr (hl, 32) ^ rotr (lh, 32) ^ hh ^ ll;
}
public:
template <typename U> U int_ (U low, U high) {
return static_cast <U> (generate () * (static_cast <double> (high) - static_cast <double> (low) + 1.0) / divider_ + static_cast <double> (low));
template <typename U, typename Void = void> U get (U, U) = delete;
template <typename Void = void> int32 get (int32 low, int32 high) {
return static_cast <int32> (wyrand32 () * (static_cast <double> (high) - static_cast <double> (low) + 1.0) / div_ + static_cast <double> (low));
}
float float_ (float low, float high) {
return static_cast <float> (generate () * (static_cast <double> (high) - static_cast <double> (low)) / (divider_ - 1) + static_cast <double> (low));
template <typename Void = void> float get (float low, float high) {
return static_cast <float> (wyrand32 () * (static_cast <double> (high) - static_cast <double> (low)) / (div_ - 1) + static_cast <double> (low));
}
template <typename U> bool chance (const U max, const U maxChance = 100) {
return int_ <U> (0, maxChance) < max;
public:
bool chance (int32 limit) {
return get <int32> (0, 100) < limit;
}
};