CGAL users discussion list

[Indranil Chowdhury <>]

Hi,

   I am new to the CGAL mailing list. I am playing with CGAL triangulation lately, and am trying to use my own double number type to pass to CGAL and want all computations that the CGAL kernel does to use this only (specially the comparison operators). Currently I am not concerned with speed, but want the kernel to interprete anything less than a threshold to be zero. 

Code :

#include <boost\operators.hpp>
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>

//a number type to overload all floating point operations

struct myDouble : boost::operators<myDouble>
{
  double val;

  myDouble( double f )
  {val = f;}
  myDouble( const myDouble &f ):
    val(f.val){}

//arithmetic operators...

 

//logical operators

  bool operator<(const myDouble &other ) const
  {
    bool isEqual = (std::abs(val-other.val) < c_zero);//c_zero is a given threshold
    return ( !isEqual && val<other.val );
  }
  bool operator==(const myDouble &other ) const
  {
    return ( std::abs(val-other.val) < c_zero );
  }
};

///From definition of inexact kernels

namespace CGAL
{
  // A modification of inexact kernel from CGAL 
  class Epick_cgal2DSurf
    : public Filtered_kernel_adaptor<
    Type_equality_wrapper< Simple_cartesian<myDouble>::Base<Epick_cgal2DSurf>::Type, Epick_cgal2DSurf >,
#ifdef CGAL_NO_STATIC_FILTERS
    false >
#else
    true >
#endif
  {   
  };
}

I get compilation error :

Error    1    error C2440: '<function-style-cast>' : cannot convert from 'const CgalDouble' to 'CGAL::Gmpq'    E:\AnsysDev\3rdparty\CGAL\CGAL-4.4\include\CGAL\NT_converter.h    41

and I am not sure how to get this code to compile.

My questions are:

1. Is there any way for CGAL to accept this numberType and get it  compiled?

2. Is there any other way to tell CGAL that any quantity less than specified is zero?

Thank you

Indranil