// gsl_test_beta.cxx
// Castelier Etienne
// 19 jan 2007
//
// Test de la fonction Beta de la GSL
//

#include <iostream>
#include <gsl/gsl_sf_gamma.h>

#include <sys/time.h>
#include <sys/resource.h>
#include <unistd.h>
#include <sys/times.h>
#include <asm/msr.h>

class IntelTimer {

public:

  IntelTimer( void ):_frequency(1.0)
  {
    find_frequency();
  }

  inline void start( void ){
    rdtsc(_click_start.n32[0],_click_start.n32[1]);
  }

  inline void stop( void ){
    rdtsc(_click_stop.n32[0],_click_stop.n32[1]);
  }

  unsigned long long  get_click( void ){
    return (_click_stop.n64-_click_start.n64);
  }    

  inline void find_frequency( void ){

    time_t initial, final;
    int dummy=2;

    initial = time(0);
    start();
    do {
      dummy+=2;
    }
    while(time(0)==initial);
    // On est au debut d'un cycle d'une seconde !!!
    initial = time(0);
    start();
    do {
      dummy+=2;
    }
    while(time(0)==initial);
    stop();
    final=time(0);
    //    _frequency=get_click()/double(final-initial);
    _frequency=get_click();
    std::cerr << "CPU frequency : "<<  _frequency << std::endl;        

  }

private:

  union
  {
    unsigned long int n32[2] ;
    unsigned long long n64 ;
  } _click_start;

  union
  {
    unsigned long int n32[2] ;
    unsigned long long n64 ;
  } _click_stop;

  double _frequency ;
};

using namespace std;

// test
void test_gsl() {
  double Ib,Ig;
  double z,w,mf,mm;
  IntelTimer timer;
  long long t1,t2;
  int n,i;

  mm=4.9;
  mf=3.9;
  
  w=mf;
  z=mm+1;

  n=10;
  cout << "Beta CPU    Gamma CPU\n";
  for(i=1; i<= n; ++i)  {
    
    timer.start();
    Ib=gsl_sf_beta(z,w);
    timer.stop();
    t1=timer.get_click();
    
    timer.start();
    Ig=gsl_sf_gamma(z)*gsl_sf_gamma(w)/gsl_sf_gamma(w+z);
    timer.stop();
    t2=timer.get_click();
    
//     cout << Ib << ' ' << Ig << endl;
    cout << "Loop " << i << endl;
    cout << t1 << ' ' << t2 << endl;
  }

}


// Routine principale
int main() {
  test_gsl();
  return 0;
}