CGAL users discussion list

[Samaras <>]

Dear all,

   I want to compute the norm() of point in D dimension. I am extending the
point_d class.
   I use these typedefs:
   #include <CGAL/Cartesian_d.h>
   #include <CGAL/Gmpq.h>

   typedef CGAL::Gmpq              NT;
   typedef CGAL::Cartesian_d<NT>   Kernel;
   typedef Kernel::Point_d         PointD;

    This is the method I am using sqrt() in:
    NT norm() const {
                NT result = 0;
                for(int i = 0 ; i < this->dimension() ; ++i)
                        result += this->cartesian(i) * this->cartesian(i);
                return sqrt(result);                                          
         
// The problem
        }

    I receive errors both in the return of sqrt and in the passing of the
argument inside. By the way, I printed the result just before the call to
sqrt() and it was 3/1 (thus 3).

    Compiler says:
/home/samaras/code/testProj/bla.cpp: In member function ‘NT Point::norm()
const’:
/home/samaras/code/testProj/bla.cpp:117:35: error: could not convert
‘CGAL::sqrt [with AS = CGAL::Gmpq, typename
CGAL::Algebraic_structure_traits<Type_>::Sqrt::result_type =
CGAL::Null_tag]((*(const CGAL::Gmpq*)(& result)))’ from
‘CGAL::Null_functor::result_type {aka CGAL::Null_tag}’ to ‘NT {aka
CGAL::Gmpq}’

/home/samaras/code/CGAL-4.3/include/CGAL/number_utils.h: In function
‘typename CGAL::Algebraic_structure_traits<Type_>::Sqrt::result_type
CGAL::sqrt(const AS&) [with AS = CGAL::Gmpq, typename
CGAL::Algebraic_structure_traits<Type_>::Sqrt::result_type =
CGAL::Null_tag]’:
/home/samaras/code/testProj/bla.cpp:117:35:   instantiated from here
/home/samaras/code/CGAL-4.3/include/CGAL/number_utils.h:103:20: error: no
match for call to ‘(CGAL::Algebraic_structure_traits_base<CGAL::Gmpq,
CGAL::Null_tag>::Sqrt {aka CGAL::Null_functor}) (const CGAL::Gmpq&)’


What is the newbie missing?
George




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