Class template faure_engine

boost::random::faure_engine

Synopsis

// In header: <boost/random/faure.hpp>

template<typename RealType, typename SeqSizeT, 
         typename PrimeTable = default_faure_prime_table> 
class faure_engine {
public:
  // types
  typedef RealType result_type;

  // construct/copy/destruct
  explicit faure_engine(std::size_t);

  // friend functions
  friend bool operator==(const faure_engine &, const faure_engine &);
  friend bool operator!=(const faure_engine &, const faure_engine &);
  template<typename CharT, typename Traits> 
    friend std::basic_ostream< CharT, Traits > & 
    operator<<(std::basic_ostream< CharT, Traits > &, const faure_engine &);
  template<typename CharT, typename Traits> 
    friend std::basic_istream< CharT, Traits > & 
    operator>>(std::basic_istream< CharT, Traits > &, const faure_engine &);

  // public static functions
  static constexpr result_type min();
  static constexpr result_type max();

  // public member functions
  void seed(SeqSizeT = 0);
  std::size_t dimension() const;
  result_type operator()();
  void discard(boost::uintmax_t);
};

Description

Instantiations of class template faure_engine model a quasi-random number generator . The faure_engine uses the algorithm described in

Henri Faure, Discrepance de suites associees a un systeme de numeration (en dimension s), Acta Arithmetica, Volume 41, 1982, pages 337-351.

Bennett Fox, Algorithm 647: Implementation and Relative Efficiency of Quasirandom Sequence Generators, ACM Transactions on Mathematical Software, Volume 12, Number 4, December 1986, pages 362-376.

In the following documentation X denotes the concrete class of the template faure_engine returning objects of type RealType, u and v are the values of X.

Some member functions may throw exceptions of type std::bad_alloc.

`faure_engine` public construct/copy/destruct

```
explicit faure_engine(std::size_t s);
```
Effects: Constructs the s-dimensional default Faure quasi-random number generator.

Throws: bad_alloc, invalid_argument.

`faure_engine` friend functions

friend bool operator==(const faure_engine & x, const faure_engine & y);

Returns true if the two generators will produce identical sequences of outputs.

friend bool operator!=(const faure_engine & lhs, const faure_engine & rhs);

Returns true if the two generators will produce different sequences of outputs.

template<typename CharT, typename Traits> 
  friend std::basic_ostream< CharT, Traits > & 
  operator<<(std::basic_ostream< CharT, Traits > & os, const faure_engine & s);

Writes the textual representation of the generator to a std::ostream.

template<typename CharT, typename Traits> 
  friend std::basic_istream< CharT, Traits > & 
  operator>>(std::basic_istream< CharT, Traits > & is, const faure_engine & s);

Reads the textual representation of the generator from a std::istream.

`faure_engine` public static functions

```
static constexpr result_type min();
```
Returns: Tight lower bound on the set of values returned by operator().

Throws: nothing.
```
static constexpr result_type max();
```
Returns: Tight upper bound on the set of values returned by operator().

Throws: nothing.

`faure_engine` public member functions

void seed(SeqSizeT init = 0);

Effects: Effectively sets the quasi-random number generator state to the init-th vector in the s-dimensional quasi-random domain, where s == X::dimension().

X u, v;
for(int i = 0; i < N; ++i)
    for( std::size_t j = 0; j < u.dimension(); ++j )
        u();
v.seed(N);
assert(u() == v());

Throws: bad_alloc.

```
std::size_t dimension() const;
```
Returns: The dimension of of the quasi-random domain.

Throws: nothing.
```
result_type operator()();
```
Returns: Returns a successive element of an s-dimensional (s = X::dimension()) vector at each invocation. When all elements are exhausted, X::operator() begins anew with the starting element of a subsequent s-dimensional vector.

Throws: range_error.

void discard(boost::uintmax_t z);

Effects: Advances *this state as if z consecutive X::operator() invocations were executed.

X u = v;
for(int i = 0; i < N; ++i)
    u();
v.discard(N);
assert(u() == v());

Throws: range_error. Throws: bad_alloc.

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