#include "xbt/random.hpp"
#include "xbt/asserts.h"
#include <limits>
-#include <random>
+#include <memory>
namespace simgrid {
namespace xbt {
namespace random {
-enum xbt_random_implem { XBT_RNG_xbt, XBT_RNG_std };
-static xbt_random_implem rng_implem = XBT_RNG_xbt;
-static std::mt19937 mt19937_gen;
-
-void set_implem_xbt()
+int StdRandom::uniform_int(int min, int max)
{
- rng_implem = XBT_RNG_xbt;
+ std::uniform_int_distribution<> dist(min, max);
+ return dist(mt19937_gen);
}
-void set_implem_std()
+
+double StdRandom::uniform_real(double min, double max)
{
- rng_implem = XBT_RNG_std;
+ std::uniform_real_distribution<> dist(min, max);
+ return dist(mt19937_gen);
}
-void set_mersenne_seed(int seed)
+
+double StdRandom::exponential(double lambda)
{
- mt19937_gen.seed(seed);
+ std::exponential_distribution<> dist(lambda);
+ return dist(mt19937_gen);
}
-int uniform_int(int min, int max)
+double StdRandom::normal(double mean, double sd)
{
- if (rng_implem == XBT_RNG_std) {
- std::uniform_int_distribution<> dist(min, max);
- return dist(mt19937_gen);
- }
+ std::normal_distribution<> dist(mean, sd);
+ return dist(mt19937_gen);
+}
+int XbtRandom::uniform_int(int min, int max)
+{
unsigned long range = max - min + 1;
- unsigned long value = mt19937_gen();
xbt_assert(min <= max,
"The minimum value for the uniform integer distribution must not be greater than the maximum value");
xbt_assert(range > 0, "Overflow in the uniform integer distribution, please use a smaller range.");
- while (value >= decltype(mt19937_gen)::max() - decltype(mt19937_gen)::max() % range) {
+ unsigned long value;
+ do {
value = mt19937_gen();
- }
+ } while (value >= decltype(mt19937_gen)::max() - decltype(mt19937_gen)::max() % range);
return value % range + min;
}
-double uniform_real(double min, double max)
+double XbtRandom::uniform_real(double min, double max)
{
- if (rng_implem == XBT_RNG_std) {
- std::uniform_real_distribution<> dist(min, max);
- return dist(mt19937_gen);
- }
-
// This reuses Boost's uniform real distribution ideas
constexpr unsigned long divisor = decltype(mt19937_gen)::max() - decltype(mt19937_gen)::min();
- unsigned long numerator = mt19937_gen() - decltype(mt19937_gen)::min();
+ unsigned long numerator;
+ do {
+ numerator = mt19937_gen() - decltype(mt19937_gen)::min();
+ } while (numerator == divisor);
return min + (max - min) * numerator / divisor;
}
-double exponential(double lambda)
+double XbtRandom::exponential(double lambda)
{
- if (rng_implem == XBT_RNG_std) {
- std::exponential_distribution<> dist(lambda);
- return dist(mt19937_gen);
- }
-
return -1.0 / lambda * log(uniform_real(0.0, 1.0));
}
-double normal(double mean, double sd)
+double XbtRandom::normal(double mean, double sd)
{
- if (rng_implem == XBT_RNG_std) {
- std::normal_distribution<> dist(mean, sd);
- return dist(mt19937_gen);
- }
-
- double u1 = 0.0;
- while (u1 < std::numeric_limits<double>::min()) {
+ double u1;
+ do {
u1 = uniform_real(0.0, 1.0);
- }
+ } while (u1 < std::numeric_limits<double>::min());
double u2 = uniform_real(0.0, 1.0);
double z0 = sqrt(-2.0 * log(u1)) * cos(2.0 * M_PI * u2);
return z0 * sd + mean;
}
+static std::unique_ptr<Random> default_random(new XbtRandom);
+
+void set_implem_xbt()
+{
+ default_random.reset(new XbtRandom);
+}
+void set_implem_std()
+{
+ default_random.reset(new StdRandom);
+}
+
+void set_mersenne_seed(int seed)
+{
+ default_random->set_seed(seed);
+}
+
+int uniform_int(int min, int max)
+{
+ return default_random->uniform_int(min, max);
+}
+
+double uniform_real(double min, double max)
+{
+ return default_random->uniform_real(min, max);
+}
+
+double exponential(double lambda)
+{
+ return default_random->exponential(lambda);
+}
+
+double normal(double mean, double sd)
+{
+ return default_random->normal(mean, sd);
+}
+
} // namespace random
} // namespace xbt
} // namespace simgrid