-/* Copyright (c) 2019-2021. The SimGrid Team. All rights reserved. */
+/* Copyright (c) 2019-2023. The SimGrid Team. All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
* under the terms of the license (GNU LGPL) which comes with this package. */
XBT_LOG_EXTERNAL_CATEGORY(xbt);
XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_random, xbt, "Random");
-namespace simgrid {
-namespace xbt {
-namespace random {
+namespace simgrid::xbt::random {
bool Random::read_state(const std::string& filename)
{
int StdRandom::uniform_int(int min, int max)
{
- std::uniform_int_distribution<> dist(min, max);
+ std::uniform_int_distribution dist(min, max);
return dist(mt19937_gen);
}
double StdRandom::uniform_real(double min, double max)
{
- std::uniform_real_distribution<> dist(min, max);
+ std::uniform_real_distribution dist(min, max);
return dist(mt19937_gen);
}
double StdRandom::exponential(double lambda)
{
- std::exponential_distribution<> dist(lambda);
+ std::exponential_distribution dist(lambda);
return dist(mt19937_gen);
}
double StdRandom::normal(double mean, double sd)
{
- std::normal_distribution<> dist(mean, sd);
+ std::normal_distribution dist(mean, sd);
return dist(mt19937_gen);
}
int XbtRandom::uniform_int(int min, int max)
{
- unsigned long range = max - min + 1;
+ // The casts to unsigned are here to ensure that the value of range is correctly calculated, even when greater than
+ // INT_MAX. See the corresponding unit tests for examples.
+ unsigned long range = static_cast<unsigned>(max) - static_cast<unsigned>(min);
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.");
+ xbt_assert(range <= decltype(mt19937_gen)::max(),
+ "Overflow in the uniform integer distribution, please use a smaller range.");
+ if (range == decltype(mt19937_gen)::max())
+ return static_cast<int>(mt19937_gen() + min);
+
+ ++range;
+ unsigned long limit = 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);
+ } while (value >= limit);
return static_cast<int>(value % range + min);
}
return default_random->normal(mean, sd);
}
-} // namespace random
-} // namespace xbt
-} // namespace simgrid
+} // namespace simgrid::xbt::random