↰ Return to documentation for file (include/networkit/auxiliary/Random.hpp)
/*
* Random.hpp
*
* Created on: 02.01.2014
* Author: FJW
*/
#ifndef NETWORKIT_AUXILIARY_RANDOM_HPP_
#define NETWORKIT_AUXILIARY_RANDOM_HPP_
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <random>
#include <stdexcept>
namespace Aux {
namespace Random {
void setSeed(uint64_t seed, bool useThreadId);
uint64_t getSeed();
std::mt19937_64 &getURNG();
uint64_t integer();
uint64_t integer(uint64_t upperBound);
uint64_t integer(uint64_t lowerBound, uint64_t upperBound);
double real();
double real(double upperBound);
double real(double lowerBound, double upperBound);
double probability();
std::size_t index(std::size_t max);
template <typename Container>
typename Container::const_reference choice(const Container &container) {
return container[index(container.size())];
}
template <typename Element>
const Element &weightedChoice(const std::vector<std::pair<Element, double>> &weightedElements) {
if (weightedElements.empty())
throw std::runtime_error("Random::weightedChoice: input size equal to 0");
double total = 0.0;
for (const auto &entry : weightedElements) {
assert(entry.second >= 0.0 && "This algorithm only works with non-negative weights");
total += entry.second;
}
double r = Aux::Random::real(total);
for (const auto &entry : weightedElements) {
if (r < entry.second) {
return entry.first;
}
r -= entry.second;
}
throw std::runtime_error(
"Random::weightedChoice: should never get here"); // should never get here
}
} // namespace Random
} // namespace Aux
#endif // NETWORKIT_AUXILIARY_RANDOM_HPP_