external/dream/rnglib.cpp

# include <cstdlib>
# include <iostream>
# include <iomanip>
# include <ctime>

using namespace std;

# include "rnglib.hpp"

namespace dream {

//****************************************************************************80

void advance_state ( int k )

//****************************************************************************80
//
//  Purpose:
//
//    ADVANCE_STATE advances the state of the current generator.
//
//  Discussion:
//
//    This procedure advances the state of the current generator by 2^K
//    values and resets the initial seed to that value.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    30 March 2013
//
//  Author:
//
//    Original Pascal version by Pierre L'Ecuyer, Serge Cote.
//    C++ version by John Burkardt.
//
//  Reference:
//
//    Pierre LEcuyer, Serge Cote,
//    Implementing a Random Number Package with Splitting Facilities,
//    ACM Transactions on Mathematical Software,
//    Volume 17, Number 1, March 1991, pages 98-111.
//
//  Parameters:
//
//    Input, int K, indicates that the generator is to be
//    advanced by 2^K values.
//    0 <= K.
//
{
  const int a1 = 40014;
  const int a2 = 40692;
  int b1;
  int b2;
  int cg1;
  int cg2;
  int g;
  int i;
  const int m1 = 2147483563;
  const int m2 = 2147483399;

  if ( k < 0 )
  {
    cerr << "\n";
    cerr << "ADVANCE_STATE - Fatal error!\n";
    cerr << "  Input exponent K is out of bounds.\n";
    exit ( 1 );
  }
//
//  Check whether the package must be initialized.
//
  if ( ! initialized_get ( ) )
  {
    cout << "\n";
    cout << "ADVANCE_STATE - Note:\n";
    cout << "  Initializing RNGLIB package.\n";
    initialize ( );
  }
//
//  Get the current generator index.
//
  g = cgn_get ( );

  b1 = a1;
  b2 = a2;

  for ( i = 1; i <= k; k++ )
  {
    b1 = multmod ( b1, b1, m1 );
    b2 = multmod ( b2, b2, m2 );
  }

  cg_get ( g, cg1, cg2 );
  cg1 = multmod ( b1, cg1, m1 );
  cg2 = multmod ( b2, cg2, m2 );
  cg_set ( g, cg1, cg2 );

  return;
}
//****************************************************************************80

bool antithetic_get ( )

//***************************************************************************80
//
//  Purpose:
//
//    ANTITHETIC_GET queries the antithetic value for a given generator.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    02 April 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Output, bool ANTITHETIC_GET, is TRUE if generator G is antithetic.
//
{
  int i;
  bool value;

  i = -1;
  antithetic_memory ( i, value );

  return value;
}
//****************************************************************************80

void antithetic_memory ( int i, bool &value )

//****************************************************************************80
//
//  Purpose:
//
//    ANTITHETIC_MEMORY stores the antithetic value for all generators.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    02 April 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Input, int I, the desired action.
//    -1, get a value.
//    0, initialize all values.
//    1, set a value.
//
//    Input/output, bool &VALUE.  For I = -1, VALUE is an output
//    quantity, if I = +1, then VALUE is an input quantity.
//
{
# define G_MAX 32

  static bool a_save[G_MAX];
  int g;
  const int g_max = 32;
  int j;

  if ( i < 0 )
  {
    g = cgn_get ( );
    value = a_save[g];
  }
  else if ( i == 0 )
  {
    for ( j = 0; j < g_max; j++ )
    {
      a_save[j] = false;
    }
  }
  else if ( 0 < i )
  {
    g = cgn_get ( );
    a_save[g] = value;
  }

  return;
# undef G_MAX
}
//****************************************************************************80

void antithetic_set ( bool value )

//****************************************************************************80
//
//  Purpose:
//
//    ANTITHETIC_SET sets the antithetic value for a given generator.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    02 April 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Input, bool VALUE, is TRUE if generator G is to be antithetic.
//
{
  int i;

  i = +1;
  antithetic_memory ( i, value );

  return;
}
//****************************************************************************80

void cg_get ( int g, int &cg1, int &cg2 )

//****************************************************************************80
//
//  Purpose:
//
//    CG_GET queries the CG values for a given generator.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    27 March 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Input, int G, the index of the generator.
//    0 <= G <= 31.
//
//    Output, int &CG1, &CG2, the CG values for generator G.
//
{
  int i;

  i = -1;
  cg_memory ( i, g, cg1, cg2 );

  return;
}
//****************************************************************************80

void cg_memory ( int i, int g, int &cg1, int &cg2 )

//****************************************************************************80
//
//  Purpose:
//
//    CG_MEMORY stores the CG values for all generators.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    30 March 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Input, int I, the desired action.
//    -1, get a value.
//    0, initialize all values.
//    1, set a value.
//
//    Input, int G, for I = -1 or +1, the index of
//    the generator, with 0 <= G <= 31.
//
//    Input/output, int &CG1, &CG2.  For I = -1,
//    these are output, for I = +1, these are input, for I = 0,
//    these arguments are ignored.  When used, the arguments are
//    old or new values of the CG parameter for generator G.
//
{
# define G_MAX 32

  static int cg1_save[G_MAX];
  static int cg2_save[G_MAX];
  const int g_max = 32;
  int j;

  if ( g < 0 || g_max <= g )
  {
    cerr << "\n";
    cerr << "CG_MEMORY - Fatal error!\n";
    cerr << "  Input generator index G is out of bounds.\n";
    exit ( 1 );
  }

  if ( i < 0 )
  {
    cg1 = cg1_save[g];
    cg2 = cg2_save[g];
  }
  else if ( i == 0 )
  {
    for ( j = 0; j < g_max; j++ )
    {
      cg1_save[j] = 0;
      cg2_save[j] = 0;
    }
  }
  else if ( 0 < i )
  {
    cg1_save[g] = cg1;
    cg2_save[g] = cg2;
  }

  return;
# undef G_MAX
}
//****************************************************************************80

void cg_set ( int g, int cg1, int cg2 )

//****************************************************************************80
//
//  Purpose:
//
//    CG_SET sets the CG values for a given generator.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    27 March 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Input, int G, the index of the generator.
//    0 <= G <= 31.
//
//    Input, int CG1, CG2, the CG values for generator G.
//
{
  int i;

  i = +1;
  cg_memory ( i, g, cg1, cg2 );

  return;
}
//****************************************************************************80

int cgn_get ( )

//****************************************************************************80
//
//  Purpose:
//
//    CGN_GET gets the current generator index.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    30 March 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Output, int CGN_GET, the current generator index.
//
{
  int g;
  int i;

  i = -1;
  cgn_memory ( i, g );

  return g;
}
//****************************************************************************80

void cgn_memory ( int i, int &g )

//****************************************************************************80
//
//  Purpose:
//
//    CGN_MEMORY stores the current generator index.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    02 April 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Input, int I, the desired action.
//    -1, get the value.
//    0, initialize the value.
//    1, set the value.
//
//    Input/output, int &G.  For I = -1 or 0, this is output.
//    For I = +1, this is input.
//
{
# define G_MAX 32

  static int g_save = 0;
  const int g_max = 32;

  if ( i < 0 )
  {
    g = g_save;
  }
  else if ( i == 0 )
  {
    g_save = 0;
    g = g_save;
  }
  else if ( 0 < i )
  {

    if ( g < 0 || g_max <= g )
    {
      cerr << "\n";
      cerr << "CGN_MEMORY - Fatal error!\n";
      cerr << "  Input generator index G is out of bounds.\n";
      exit ( 1 );
    }

    g_save = g;
  }

  return;
# undef G_MAX
}
//****************************************************************************80

void cgn_set ( int g )

//****************************************************************************80
//
//  Purpose:
//
//    CGN_SET sets the current generator index.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    30 March 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Input, int G, the current generator index.
//    0 <= G <= 31.
//
{
  int i;

  i = +1;
  cgn_memory ( i, g );

  return;
}
//****************************************************************************80

void get_state ( int &cg1, int &cg2 )

//****************************************************************************80
//
//  Purpose:
//
//    GET_STATE returns the state of the current generator.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    30 March 2013
//
//  Author:
//
//    Original Pascal version by Pierre L'Ecuyer, Serge Cote.
//    C++ version by John Burkardt.
//
//  Reference:
//
//    Pierre LEcuyer, Serge Cote,
//    Implementing a Random Number Package with Splitting Facilities,
//    ACM Transactions on Mathematical Software,
//    Volume 17, Number 1, March 1991, pages 98-111.
//
//  Parameters:
//
//    Output, int *CG1, *CG2, the CG values for the current generator.
//
{
  int g;
//
//  Check whether the package must be initialized.
//
  if ( ! initialized_get ( ) )
  {
    cout << "\n";
    cout << "GET_STATE - Note:\n";
    cout << "  Initializing RNGLIB package.\n";
    initialize ( );
  }
//
//  Get the current generator index.
//
  g = cgn_get ( );
//
//  Retrieve the seed values for this generator.
//
  cg_get ( g, cg1, cg2 );

  return;
}
//****************************************************************************80

int i4_uniform ( )

//****************************************************************************80
//
//  Purpose:
//
//    I4_UNIFORM generates a random positive integer.
//
//  Discussion:
//
//    This procedure returns a random integer following a uniform distribution
//    over (1, 2147483562) using the current generator.
//
//    The original name of this function was "random()", but this conflicts
//    with a standard library function name in C.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    02 April 2013
//
//  Author:
//
//    Original Pascal version by Pierre L'Ecuyer, Serge Cote.
//    C++ version by John Burkardt.
//
//  Reference:
//
//    Pierre LEcuyer, Serge Cote,
//    Implementing a Random Number Package with Splitting Facilities,
//    ACM Transactions on Mathematical Software,
//    Volume 17, Number 1, March 1991, pages 98-111.
//
//  Parameters:
//
//    Output, int I4_UNIFORM, the random integer.
//
{
  const int a1 = 40014;
  const int a2 = 40692;
  int cg1;
  int cg2;
  int g;
  int k;
  const int m1 = 2147483563;
  const int m2 = 2147483399;
  bool value;
  int z;
//
//  Check whether the package must be initialized.
//
  if ( ! initialized_get ( ) )
  {
    cout << "\n";
    cout << "I4_UNIFORM - Note:\n";
    cout << "  Initializing RNGLIB package.\n";
    initialize ( );
  }
//
//  Get the current generator index.
//
  g = cgn_get ( );
//
//  Retrieve the current seeds.
//
  cg_get ( g, cg1, cg2 );
//
//  Update the seeds.
//
  k = cg1 / 53668;
  cg1 = a1 * ( cg1 - k * 53668 ) - k * 12211;

  if ( cg1 < 0 )
  {
    cg1 = cg1 + m1;
  }

  k = cg2 / 52774;
  cg2 = a2 * ( cg2 - k * 52774 ) - k * 3791;

  if ( cg2 < 0 )
  {
    cg2 = cg2 + m2;
  }
//
//  Store the updated seeds.
//
  cg_set ( g, cg1, cg2 );
//
//  Form the random integer.
//
  z = cg1 - cg2;

  if ( z < 1 )
  {
    z = z + m1 - 1;
  }
//
//  If the generator is antithetic, reflect the value.
//
  value = antithetic_get ( );

  if ( value )
  {
    z = m1 - z;
  }
  return z;
}
//****************************************************************************80

void ig_get ( int g, int &ig1, int &ig2 )

//****************************************************************************80
//
//  Purpose:
//
//    IG_GET queries the IG values for a given generator.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    27 March 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Input, int G, the index of the generator.
//    0 <= G <= 31.
//
//    Output, int &IG1, &IG2, the IG values for generator G.
//
{
  int i;

  i = -1;
  ig_memory ( i, g, ig1, ig2 );

  return;
}
//****************************************************************************80

void ig_memory ( int i, int g, int &ig1, int &ig2 )

//****************************************************************************80
//
//  Purpose:
//
//    IG_MEMORY stores the IG values for all generators.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    30 March 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Input, int I, the desired action.
//    -1, get a value.
//    0, initialize all values.
//    1, set a value.
//
//    Input, int G, for I = -1 or +1, the index of
//    the generator, with 0 <= G <= 31.
//
//    Input/output, int &IG1, &IG2.  For I = -1,
//    these are output, for I = +1, these are input, for I = 0,
//    these arguments are ignored.  When used, the arguments are
//    old or new values of the IG parameter for generator G.
//
{
# define G_MAX 32

  const int g_max = 32;
  static int ig1_save[G_MAX];
  static int ig2_save[G_MAX];
  int j;

  if ( g < 0 || g_max <= g )
  {
    cerr << "\n";
    cerr << "IG_MEMORY - Fatal error!\n";
    cerr << "  Input generator index G is out of bounds.\n";
    exit ( 1 );
  }

  if ( i < 0 )
  {
    ig1 = ig1_save[g];
    ig2 = ig2_save[g];
  }
  else if ( i == 0 )
  {
    for ( j = 0; j < g_max; j++ )
    {
      ig1_save[j] = 0;
      ig2_save[j] = 0;
    }
  }
  else if ( 0 < i )
  {
    ig1_save[g] = ig1;
    ig2_save[g] = ig2;
  }

  return;
# undef G_MAX
}
//****************************************************************************80

void ig_set ( int g, int ig1, int ig2 )

//****************************************************************************80
//
//  Purpose:
//
//    IG_SET sets the IG values for a given generator.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    27 March 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Input, int G, the index of the generator.
//    0 <= G <= 31.
//
//    Input, int IG1, IG2, the IG values for generator G.
//
{
  int i;

  i = +1;
  ig_memory ( i, g, ig1, ig2 );

  return;
}
//****************************************************************************80

void init_generator ( int t )

//****************************************************************************80
//
//  Purpose:
//
//    INIT_GENERATOR sets the state of generator G to initial, last or new seed.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    02 April 2013
//
//  Author:
//
//    Original Pascal version by Pierre L'Ecuyer, Serge Cote.
//    C++ version by John Burkardt.
//
//  Reference:
//
//    Pierre LEcuyer, Serge Cote,
//    Implementing a Random Number Package with Splitting Facilities,
//    ACM Transactions on Mathematical Software,
//    Volume 17, Number 1, March 1991, pages 98-111.
//
//  Parameters:
//
//    Input, int T, the seed type:
//    0, use the seed chosen at initialization time.
//    1, use the last seed.
//    2, use a new seed set 2^30 values away.
//
{
  const int a1_w = 1033780774;
  const int a2_w = 1494757890;
  int cg1;
  int cg2;
  int g;
  int ig1;
  int ig2;
  int lg1;
  int lg2;
  const int m1 = 2147483563;
  const int m2 = 2147483399;
//
//  Check whether the package must be initialized.
//
  if ( ! initialized_get ( ) )
  {
    cout << "\n";
    cout << "INIT_GENERATOR - Note:\n";
    cout << "  Initializing RNGLIB package.\n";
    initialize ( );
  }
//
//  Get the current generator index.
//
  g = cgn_get ( );
//
//  0: restore the initial seed.
//
  if ( t == 0 )
  {
    ig_get ( g, ig1, ig2 );
    lg1 = ig1;
    lg2 = ig2;
    lg_set ( g, lg1, lg2 );
  }
//
//  1: restore the last seed.
//
  else if ( t == 1 )
  {
    lg_get ( g, lg1, lg2 );
  }
//
//  2: Advance to a new seed.
//
  else if ( t == 2 )
  {
    lg_get ( g, lg1, lg2 );
    lg1 = multmod ( a1_w, lg1, m1 );
    lg2 = multmod ( a2_w, lg2, m2 );
    lg_set ( g, lg1, lg2 );
  }
  else
  {
    cerr << "\n";
    cerr << "INIT_GENERATOR - Fatal error!\n";
    cerr << "  Input parameter T out of bounds.\n";
    exit ( 1 );
  }
//
//  Store the new seed.
//
  cg1 = lg1;
  cg2 = lg2;
  cg_set ( g, cg1, cg2 );

  return;
}
//****************************************************************************80

void initialize ( )

//****************************************************************************80
//
//  Purpose:
//
//    INITIALIZE initializes the random number generator library.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    30 March 2013
//
//  Author:
//
//    Original Pascal version by Pierre L'Ecuyer, Serge Cote.
//    C++ version by John Burkardt.
//
//  Reference:
//
//    Pierre LEcuyer, Serge Cote,
//    Implementing a Random Number Package with Splitting Facilities,
//    ACM Transactions on Mathematical Software,
//    Volume 17, Number 1, March 1991, pages 98-111.
//
//  Parameters:
//
//    None
//
{
  int g;
  const int g_max = 32;
  int ig1;
  int ig2;
  int value;
//
//  Remember that we have called INITIALIZE().
//
  initialized_set ( );
//
//  Initialize all generators to have FALSE antithetic value.
//
  value = 0;
  for ( g = 0; g < g_max; g++ )
  {
    cgn_set ( g );
    antithetic_set ( value );
  }
//
//  Set the initial seeds.
//
  ig1 = 1234567890;
  ig2 = 123456789;
  set_initial_seed ( ig1, ig2 );
//
//  Initialize the current generator index to 0.
//
  g = 0;
  cgn_set ( g );

  cout << "\n";
  cout << "INITIALIZE - Note:\n";
  cout << "  The RNGLIB package has been initialized.\n";

  return;
}
//****************************************************************************80

bool initialized_get ( )

//****************************************************************************80
//
//  Purpose:
//
//    INITIALIZED_GET queries the INITIALIZED value.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    28 March 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Output, bool INITIALIZED_GET, is TRUE (1) if the package has been initialized.
//
{
  int i;
  bool value;

  i = -1;
  initialized_memory ( i, value );

  return value;
}
//****************************************************************************80

void initialized_memory ( int i, bool &initialized )

//****************************************************************************80
//
//  Purpose:
//
//    INITIALIZED_MEMORY stores the INITIALIZED value for the package.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    28 March 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Input, int I, the desired action.
//    -1, get the value.
//    0, initialize the value.
//    1, set the value.
//
//    Input/output, bool &INITIALIZED.  For I = -1, this is an output
//    quantity.  If I = +1, this is an input quantity.  If I = 0,
//    this is ignored.
//
{
  static bool initialized_save = false;

  if ( i < 0 )
  {
    initialized = initialized_save;
  }
  else if ( i == 0 )
  {
    initialized_save = false;
  }
  else if ( 0 < i )
  {
    initialized_save = initialized;
  }

  return;
}
//****************************************************************************80

void initialized_set ( )

//****************************************************************************80
//
//  Purpose:
//
//    INITIALIZED_SET sets the INITIALIZED value true.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    28 March 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    None
//
{
  int i;
  bool initialized;

  i = +1;
  initialized = true;
  initialized_memory ( i, initialized );

  return;
}
//****************************************************************************80

void lg_get ( int g, int &lg1, int &lg2 )

//****************************************************************************80
//
//  Purpose:
//
//    LG_GET queries the LG values for a given generator.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    27 March 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Input, int G, the index of the generator.
//    0 <= G <= 31.
//
//    Output, int &LG1, &LG2, the LG values for generator G.
//
{
  int i;

  i = -1;
  lg_memory ( i, g, lg1, lg2 );

  return;
}
//****************************************************************************80

void lg_memory ( int i, int g, int &lg1, int &lg2 )

//****************************************************************************80
//
//  Purpose:
//
//    LG_MEMORY stores the LG values for all generators.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    30 March 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Input, int I, the desired action.
//    -1, get a value.
//    0, initialize all values.
//    1, set a value.
//
//    Input, int G, for I = -1 or +1, the index of
//    the generator, with 0 <= G <= 31.
//
//    Input/output, int &LG1, &LG2.  For I = -1,
//    these are output, for I = +1, these are input, for I = 0,
//    these arguments are ignored.  When used, the arguments are
//    old or new values of the LG parameter for generator G.
//
{
# define G_MAX 32

  const int g_max = 32;

  int j;
  static int lg1_save[G_MAX];
  static int lg2_save[G_MAX];

  if ( g < 0 || g_max <= g )
  {
    cerr << "\n";
    cerr << "LG_MEMORY - Fatal error!\n";
    cerr << "  Input generator index G is out of bounds.\n";
    exit ( 1 );
  }

  if ( i < 0 )
  {
    lg1 = lg1_save[g];
    lg2 = lg2_save[g];
  }
  else if ( i == 0 )
  {
    for ( j = 0; j < g_max; j++ )
    {
      lg1_save[j] = 0;
      lg2_save[j] = 0;
    }
  }
  else if ( 0 < i )
  {
    lg1_save[g] = lg1;
    lg2_save[g] = lg2;
  }
  return;
# undef G_MAX
}
//****************************************************************************80

void lg_set ( int g, int lg1, int lg2 )

//****************************************************************************80
//
//  Purpose:
//
//    LG_SET sets the LG values for a given generator.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    27 March 2013
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    Input, int G, the index of the generator.
//    0 <= G <= 31.
//
//    Input, int LG1, LG2, the LG values for generator G.
//
{
  int i;

  i = +1;
  lg_memory ( i, g, lg1, lg2 );

  return;
}
//****************************************************************************80

int multmod ( int a, int s, int m )

//****************************************************************************80
//
//  Purpose:
//
//    MULTMOD carries out modular multiplication.
//
//  Discussion:
//
//    This procedure returns
//
//      ( A * S ) mod M
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    27 March 2013
//
//  Author:
//
//    Original Pascal version by Pierre L'Ecuyer, Serge Cote.
//    C++ version by John Burkardt.
//
//  Reference:
//
//    Pierre LEcuyer, Serge Cote,
//    Implementing a Random Number Package with Splitting Facilities,
//    ACM Transactions on Mathematical Software,
//    Volume 17, Number 1, March 1991, pages 98-111.
//
//  Parameters:
//
//    Input, int A, S, M, the arguments.
//
//    Output, int MULTMOD, the value of the product of A and S,
//    modulo M.
//
{
  int a0;
  int a1;
  const int h = 32768;
  int k;
  int p;
  int q;
  int qh;
  int rh;

  if ( a <= 0 )
  {
    cerr << "\n";
    cerr << "MULTMOD - Fatal error!\n";
    cerr << "  A <= 0.\n";
    exit ( 1 );
  }

  if ( m <= a )
  {
    cerr << "\n";
    cerr << "MULTMOD - Fatal error!\n";
    cerr << "  M <= A.\n";
    exit ( 1 );
  }

  if ( s <= 0 )
  {
    cerr << "\n";
    cerr << "MULTMOD - Fatal error!\n";
    cerr << "  S <= 0.\n";
    exit ( 1 );
  }

  if ( m <= s )
  {
    cerr << "\n";
    cerr << "MULTMOD - Fatal error!\n";
    cerr << "  M <= S.\n";
    exit ( 1 );
  }

  if ( a < h )
  {
    a0 = a;
    p = 0;
  }
  else
  {
    a1 = a / h;
    a0 = a - h * a1;
    qh = m / h;
    rh = m - h * qh;

    if ( h <= a1 )
    {
      a1 = a1 - h;
      k = s / qh;
      p = h * ( s - k * qh ) - k * rh;

      while ( p < 0 )
      {
        p = p + m;
      }
    }
    else
    {
      p = 0;
    }

    if ( a1 != 0 )
    {
      q = m / a1;
      k = s / q;
      p = p - k * ( m - a1 * q );

      if ( 0 < p )
      {
        p = p - m;
      }

      p = p + a1 * ( s - k * q );

      while ( p < 0 )
      {
        p = p + m;
      }
    }

    k = p / qh;
    p = h * ( p - k * qh ) - k * rh;

    while ( p < 0 )
    {
      p = p + m;
    }
  }

  if ( a0 != 0 )
  {
    q = m / a0;
    k = s / q;
    p = p - k * ( m - a0 * q );

    if ( 0 < p )
    {
      p = p - m;
    }

    p = p + a0 * ( s - k * q );

    while ( p < 0 )
    {
      p = p + m;
    }
  }
  return p;
}
//****************************************************************************80

float r4_uniform_01 ( )

//****************************************************************************80
//
//  Purpose:
//
//    R4_UNIFORM_01 returns a uniform random real number in [0,1].
//
//  Discussion:
//
//    This procedure returns a random floating point number from a uniform
//    distribution over (0,1), not including the endpoint values, using the
//    current random number generator.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    10 April 2013
//
//  Author:
//
//    Original Pascal version by Pierre L'Ecuyer, Serge Cote.
//    C++ version by John Burkardt.
//
//  Reference:
//
//    Pierre LEcuyer, Serge Cote,
//    Implementing a Random Number Package with Splitting Facilities,
//    ACM Transactions on Mathematical Software,
//    Volume 17, Number 1, March 1991, pages 98-111.
//
//  Parameters:
//
//    Output, float R4_UNIFORM_01, a uniform random value in [0,1].
//
{
  int i;
  float value;
//
//  Check whether the package must be initialized.
//
  if ( ! initialized_get ( ) )
  {
    cout << "\n";
    cout << "R4_UNIFORM_01 - Note:\n";
    cout << "  Initializing RNGLIB package.\n";
    initialize ( );
  }
//
//  Get a random integer.
//
  i = i4_uniform ( );
//
//  Scale it to [0,1].
//
  value = ( float ) ( i ) * 4.656613057E-10;

  return value;
}
//****************************************************************************80

double r8_uniform_01 ( )

//****************************************************************************80
//
//  Purpose:
//
//    R8_UNIFORM_01 returns a uniform random double in [0,1].
//
//  Discussion:
//
//    This procedure returns a random valule from a uniform
//    distribution over (0,1), not including the endpoint values, using the
//    current random number generator.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    10 April 2013
//
//  Author:
//
//    Original Pascal version by Pierre L'Ecuyer, Serge Cote.
//    C++ version by John Burkardt.
//
//  Reference:
//
//    Pierre LEcuyer, Serge Cote,
//    Implementing a Random Number Package with Splitting Facilities,
//    ACM Transactions on Mathematical Software,
//    Volume 17, Number 1, March 1991, pages 98-111.
//
//  Parameters:
//
//    Output, double R8_UNIFORM_01, a uniform random value in [0,1].
//
{
  int i;
  double value;
//
//  Check whether the package must be initialized.
//
  if ( ! initialized_get ( ) )
  {
    cout << "\n";
    cout << "R8_UNIFORM_01 - Note:\n";
    cout << "  Initializing RNGLIB package.\n";
    initialize ( );
  }
//
//  Get a random integer.
//
  i = i4_uniform ( );
//
//  Scale it to [0,1].
//
  value = ( double ) ( i ) * 4.656613057E-10;

  return value;
}
//****************************************************************************80

void set_initial_seed ( int ig1, int ig2 )

//****************************************************************************80
//
//  Purpose:
//
//    SET_INITIAL_SEED resets the initial seed and state for all generators.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    27 March 2013
//
//  Author:
//
//    Original Pascal version by Pierre L'Ecuyer, Serge Cote.
//    C++ version by John Burkardt.
//
//  Reference:
//
//    Pierre LEcuyer, Serge Cote,
//    Implementing a Random Number Package with Splitting Facilities,
//    ACM Transactions on Mathematical Software,
//    Volume 17, Number 1, March 1991, pages 98-111.
//
//  Parameters:
//
//    Input, int IG1, IG2, the initial seed values
//    for the first generator.
//    1 <= IG1 < 2147483563
//    1 <= IG2 < 2147483399
//
{
  const int a1_vw = 2082007225;
  const int a2_vw = 784306273;
  int g;
  const int g_max = 32;
  int i;
  const int m1 = 2147483563;
  const int m2 = 2147483399;
  int t;

  if ( ig1 < 1 || m1 <= ig1 )
  {
    cerr << "\n";
    cerr << "SET_INITIAL_SEED - Fatal error!\n";
    cerr << "  Input parameter IG1 out of bounds.\n";
    exit ( 1 );
  }

  if ( ig2 < 1 || m2 <= ig2 )
  {
    cerr << "\n";
    cerr << "SET_INITIAL_SEED - Fatal error!\n";
    cerr << "  Input parameter IG2 out of bounds.\n";
    exit ( 1 );
  }
//
//  Because INITIALIZE calls SET_INITIAL_SEED, it's not easy to correct
//  the error that arises if SET_INITIAL_SEED is called before INITIALIZE.
//  So don't bother trying.
//
  if ( ! initialized_get ( ) )
  {
    cout << "\n";
    cout << "SET_INITIAL_SEED - Fatal error!\n";
    cout << "  The RNGLIB package has not been initialized.\n";
    exit ( 1 );
  }
//
//  Set the initial seed, then initialize the first generator.
//
  g = 0;
  cgn_set ( g );

  ig_set ( g, ig1, ig2 );

  t = 0;
  init_generator ( t );
//
//  Now do similar operations for the other generators.
//
  for ( g = 1; g < g_max; g++ )
  {
    cgn_set ( g );
    ig1 = multmod ( a1_vw, ig1, m1 );
    ig2 = multmod ( a2_vw, ig2, m2 );
    ig_set ( g, ig1, ig2 );
    init_generator ( t );
  }
//
//  Now choose the first generator.
//
  g = 0;
  cgn_set ( g );

  return;
}
//****************************************************************************80

void set_seed ( int cg1, int cg2 )

//****************************************************************************80
//
//  Purpose:
//
//    SET_SEED resets the initial seed and the state of generator G.
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    02 April 2013
//
//  Author:
//
//    Original Pascal version by Pierre L'Ecuyer, Serge Cote.
//    C++ version by John Burkardt.
//
//  Reference:
//
//    Pierre LEcuyer, Serge Cote,
//    Implementing a Random Number Package with Splitting Facilities,
//    ACM Transactions on Mathematical Software,
//    Volume 17, Number 1, March 1991, pages 98-111.
//
//  Parameters:
//
//    Input, int CG1, CG2, the CG values for generator G.
//    1 <= CG1 < 2147483563
//    1 <= CG2 < 2147483399
//
{
  int g;
  int i;
  const int m1 = 2147483563;
  const int m2 = 2147483399;
  int t;

  if ( cg1 < 1 || m1 <= cg1 )
  {
    cerr << "\n";
    cerr << "SET_SEED - Fatal error!\n";
    cerr << "  Input parameter CG1 out of bounds.\n";
    exit ( 1 );
  }

  if ( cg2 < 1 || m2 <= cg2 )
  {
    cerr << "\n";
    cerr << "SET_SEED - Fatal error!\n";
    cerr << "  Input parameter CG2 out of bounds.\n";
    exit ( 1 );
  }
//
//  Check whether the package must be initialized.
//
  if ( ! initialized_get ( ) )
  {
    cout << "\n";
    cout << "SET_SEED - Note:\n";
    cout << "  Initializing RNGLIB package.\n";
    initialize ( );
  }
//
//  Retrieve the current generator index.
//
  g = cgn_get ( );
//
//  Set the seeds.
//
  cg_set ( g, cg1, cg2 );
//
//  Initialize the generator.
//
  t = 0;
  init_generator ( t );

  return;
}
//****************************************************************************80

void timestamp ( )

//****************************************************************************80
//
//  Purpose:
//
//    TIMESTAMP prints the current YMDHMS date as a time stamp.
//
//  Example:
//
//    31 May 2001 09:45:54 AM
//
//  Licensing:
//
//    This code is distributed under the GNU LGPL license.
//
//  Modified:
//
//    08 July 2009
//
//  Author:
//
//    John Burkardt
//
//  Parameters:
//
//    None
//
{
# define TIME_SIZE 40

  static char time_buffer[TIME_SIZE];
  const struct std::tm *tm_ptr;
  size_t len;
  std::time_t now;

  now = std::time ( NULL );
  tm_ptr = std::localtime ( &now );

  len = std::strftime ( time_buffer, TIME_SIZE, "%d %B %Y %I:%M:%S %p", tm_ptr );

  std::cout << time_buffer << "\n";

  return;
# undef TIME_SIZE
}

}