Rng.cpp

#define RNG_CPP
#include "Rng.h"
#include <iostream>
#include <algorithm>
#include <chrono>
#include <time.h>
#include <sys/time.h>
#include <mach/clock.h>
#include <mach/mach.h>

RNG::RNG() : stdNormal(0,1), uniform01(0,1) {
  timespec ts;
  clock_serv_t cclock;
  mach_timespec_t mts;
  host_get_clock_service( mach_host_self(), CALENDAR_CLOCK, &cclock );
  clock_get_time(cclock, &mts);
  mach_port_deallocate(mach_task_self(), cclock);
  ts.tv_sec = mts.tv_sec;
  ts.tv_nsec = mts.tv_nsec;
  RNGseedGeneratorMutex.lock();
  gen.seed(RNGseedGenerator()+ts.tv_nsec);
  RNGseedGeneratorMutex.unlock();
}

int RNG::randint(int n) {
  if (n==0) return 0;
  else return gen()%n;
}
float RNG::uniform(float a, float b) {
  return a+(b-a)*uniform01(gen);
}
float RNG::normal(float mean, float sd) {
  return mean+sd*stdNormal(gen);
}
int RNG::bernoulli(float p) {
  if (uniform01(gen)<p)
    return 1;
  else
    return 0;
}
template <typename T>
int RNG::index(std::vector<T> &v) {
  if (v.size()==0) std::cout << "RNG::index called for empty std::vector!\n";
  return gen()%v.size();
}
std::vector<int> RNG::NchooseM(int n, int m) {
  std::vector<int> ret(m,100);
  int ctr=m;
  for(int i=0;i<n;i++)
    if (uniform01(gen)<ctr*1.0/(n-i)) ret[m-ctr--]=i;
  return ret;
}
std::vector<int> RNG::permutation(int n) {
  std::vector<int> ret;
  for (int i=0;i<n;i++) ret.push_back(i);
  std::shuffle ( ret.begin(), ret.end(), gen);
  return ret;
}
template <typename T> void RNG::vectorShuffle(std::vector<T> &v) {
  std::shuffle( v.begin(), v.end(), gen);
}

template void RNG::vectorShuffle<int>(std::vector<int> &v);