CGAL 5.6.1  Number Types

#include <CGAL/Mpzf.h>
An object of the class Mpzf
is a multipleprecision floatingpoint number which can represent numbers of the form \( m*2^e\), where \( m\) is an arbitrary precision integer based on the GMP library, and \( e\) is of type int
.
This type can be considered exact, even if the exponent is not a multipleprecision number. A Mpzf
constructed from an integer or a normalized finite floating point number represents exactly that number. This number type offers functionality very similar to MP_Float
and Gmpzf
but is faster.
Implementation
This class is only available on platforms on which GMP uses 64 bit limbs and the endianness is either bigendian or littleendian. The macro CGAL_HAS_MPZF
will be defined when including CGAL/Mpzf.h
if this is true. This class makes the assumption that the representation of a double
in memory follows IEEE 754.
Currently, an Mpzf
contains an array of a few limbs, in which it stores the data as long as it fits. If it does not fit, it dynamically allocates memory with new, and deallocates it when it is done. Code to recycle the allocated memory (per thread) is included but disabled at the moment.
Related Functions  
(Note that these are not member functions.)  
std::ostream &  operator<< (std::ostream &out, const Mpzf &f) 
writes a double approximation of f to the ostream out .  
std::istream &  operator>> (std::istream &in, Mpzf &f) 
reads a double from in , then converts it to a Mpzf .  
Creation  
Mpzf ()  
creates a Mpzf initialized with 0 .  
Mpzf (int i)  
creates a Mpzf initialized with i .  
Mpzf (long int l)  
creates a Mpzf initialized with l .  
Mpzf (const Gmpz &i)  
creates a Mpzf initialized with i .  
Mpzf (const mpz_class &i)  
creates a Mpzf initialized with i .  
Mpzf (double d)  
creates a Mpzf initialized with d .  
Conversion  
operator Gmpq () const  
creates a Gmpq initialized with *this .  
operator mpq_class () const  
creates a mpq_class initialized with *this .  