kazu
9947dced15
added new helper methods/classes (e.g. for heading) new test cases optimize the dijkstra cleanups/refactoring added timed-benchmarks to the log many more...
83 lines
1.6 KiB
C++
83 lines
1.6 KiB
C++
#ifndef DRAWLIST_H
|
|
#define DRAWLIST_H
|
|
|
|
#include <vector>
|
|
#include <random>
|
|
|
|
/**
|
|
* add elements of a certain probability
|
|
* and randomly draw from them
|
|
*/
|
|
template <typename T> class DrawList {
|
|
|
|
/** one entry */
|
|
struct Entry {
|
|
|
|
/** the user element */
|
|
T element;
|
|
|
|
/** the cumulative probability up to this element */
|
|
double cumProbability;
|
|
|
|
/** ctor */
|
|
Entry(T element, const double cumProbability) : element(element), cumProbability(cumProbability) {;}
|
|
|
|
/** compare for searches */
|
|
bool operator < (const double val) const {return cumProbability < val;}
|
|
|
|
};
|
|
|
|
private:
|
|
|
|
/** current cumulative probability */
|
|
double cumProbability;
|
|
|
|
/** all contained elements */
|
|
std::vector<Entry> elements;
|
|
|
|
/** random number generator */
|
|
std::minstd_rand gen;
|
|
|
|
public:
|
|
|
|
/** ctor */
|
|
DrawList() : cumProbability(0) {
|
|
;
|
|
}
|
|
|
|
/** reset */
|
|
void reset() {
|
|
cumProbability = 0;
|
|
elements.clear();
|
|
}
|
|
|
|
/** add a new user-element and its probability */
|
|
void add(T element, const double probability) {
|
|
cumProbability += probability;
|
|
elements.push_back(Entry(element, cumProbability));
|
|
}
|
|
|
|
/** get a random element based on its probability */
|
|
T get() {
|
|
|
|
// generate random number between [0:cumProbability]
|
|
std::uniform_real_distribution<> dist(0, cumProbability);
|
|
|
|
// get a random value
|
|
const double rndVal = dist(gen);
|
|
|
|
// binary search for the matching entry O(log(n))
|
|
const auto tmp = std::lower_bound(elements.begin(), elements.end(), rndVal);
|
|
return (*tmp).element;
|
|
|
|
}
|
|
|
|
/** get the current, cumulative probability */
|
|
double getCumProbability() const {
|
|
return cumProbability;
|
|
}
|
|
|
|
};
|
|
|
|
#endif // DRAWLIST_H
|