10 #include "boost/random.hpp"
12 typedef unsigned int seedType;
13 typedef boost::random::mt19937 engine_type;
14 typedef boost::random::uniform_01<> uniform_01_dist;
15 typedef boost::random::gamma_distribution<> gamma_dist;
16 typedef boost::random::variate_generator<engine_type&, uniform_01_dist> uniform_01_generator;
17 typedef boost::random::variate_generator<engine_type&, gamma_dist> gamma_generator;
21 static void init() { seedEngine = new engine_type(time(NULL)); }
22 static void init(seedType seed) { seedEngine = new engine_type(seed); }
24 static void finish() { if (seedEngine != NULL) delete seedEngine; }
26 static engine_type *new_engine() {
28 static std::set<seedType> seedSet; // empty set of seeds
29 std::set<seedType>::iterator iter;
32 seed = (*seedEngine)();
33 iter = seedSet.find(seed);
34 } while (iter != seedSet.end());
37 return new engine_type(seed);
41 static engine_type *seedEngine;
44 engine_type* engineFactory::seedEngine = NULL;
46 // arr should be cumulative!
48 // random number should be in [0, arr[len - 1])
49 // If by chance arr[len - 1] == 0.0, one possibility is to sample uniformly from 0...len-1
50 int sample(uniform_01_generator& rg, std::vector<double>& arr, int len) {
52 double prb = rg() * arr[len - 1];
57 if (arr[mid] <= prb) l = mid + 1;
61 if (l >= len) { printf("%d %lf %lf\n", len, arr[len - 1], prb); }