//*CMZ :  2.00/00 21/01/98  08.36.06  by  Rene Brun
//*CMZ :  1.03/09 05/12/97  13.19.06  by  Fons Rademakers
//*-- Author :    Rene Brun   15/12/95

//*KEEP,CopyRight,T=C.
/*************************************************************************
 * Copyright(c) 1995-1998, The ROOT System, All rights reserved.         *
 * Authors: Rene Brun, Nenad Buncic, Valery Fine, Fons Rademakers.       *
 *                                                                       *
 * Permission to use, copy, modify and distribute this software and its  *
 * documentation for non-commercial purposes is hereby granted without   *
 * fee, provided that the above copyright notice appears in all copies   *
 * and that both the copyright notice and this permission notice appear  *
 * in the supporting documentation. The authors make no claims about the *
 * suitability of this software for any purpose.                         *
 * It is provided "as is" without express or implied warranty.           *
 *************************************************************************/
//*KEND.

//////////////////////////////////////////////////////////////////////////
//                                                                      //
// TRandom                                                              //
//                                                                      //
// Simple prototype random number generator class.                      //
//                                                                      //
//////////////////////////////////////////////////////////////////////////

//*KEEP,TMath.
#include "TMath.h"
//*KEEP,TRandom,T=C++.
#include "TRandom.h"
//*KEND.

ClassImp(TRandom)

//______________________________________________________________________________
 TRandom::TRandom(): TNamed("Random","Default Random number generator")
{
//*-*-*-*-*-*-*-*-*-*-*default constructor*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
//*-*                  ===================

   fSeed = 65539;

}

//______________________________________________________________________________
 TRandom::~TRandom()
{
//*-*-*-*-*-*-*-*-*-*-*default destructor*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
//*-*                  ==================

}

//______________________________________________________________________________
 Float_t TRandom::Gaus(Float_t mean, Float_t sigma)
{
//      Return a number distributed following a gaussian with mean and sigma

   // Local variables
   Float_t x, y, z, result;

   y = Rndm();
   if (!y) y = Rndm();
   z = Rndm();
   x = z * 6.283185;
   result = mean + sigma*TMath::Sin(x)*TMath::Sqrt(-2*TMath::Log(y));
   return result;
}

//______________________________________________________________________________
 void TRandom::Rannor(Float_t &a, Float_t &b)
{
//      Return 2 numbers distributed following a gaussian with mean=0 and sigma=1

   // Local variables
   Float_t r, x, y, z;

   y = Rndm();
   if (!y) y = Rndm();
   z = Rndm();
   x = z * 6.283185;
   r = TMath::Sqrt(-2*TMath::Log(y));
   a = r * TMath::Sin(x);
   b = r * TMath::Cos(x);
}

//______________________________________________________________________________
 Float_t TRandom::Rndm(Int_t)
{
//  Machine independent random number generator.
//  Produces uniformly-distributed floating points between 0 and 1.
//  Identical sequence on all machines of >= 32 bits.
//  Universal version (Fred james 1985).

   const Float_t kCONS = 4.6566128730774E-10;
   const Int_t kMASK31 = 2147483647;

   fSeed *= 69069;
      // keep only lower 31 bits
   fSeed &= kMASK31;
      // Set lower 8 bits to zero to assure exact float
   Int_t jy = (fSeed/256)*256;
   Float_t random = kCONS*jy;
   return random;
}