CGAL users discussion list

[Kai WANG <>]

Hi Sebastien,
The reason is illustrated in another post: 

http://cgal-discuss.949826.n4.nabble.com/Issue-on-CGAL-Polygon-2-Intersection-td3877407.html

Since I find my program crash when calculating the 2D polygon intersection with CGAL::Cartesian<double> as the kernel number type, especially when there are more digits after the decimal point.
So acuturally there's confliction between differente packages in CGAL, right? Is there any beatiful solution to solve these two problems in a same project please? Thanks!

On Fri, Oct 7, 2011 at 12:28 AM, Sebastien Loriot (GeometryFactory) <> wrote:

Is there any reason why you want to use Exact_predicates_exact_constructions_kernel
and not Exact_predicates_inexact_constructions_kernel as kernel?

Sebastien.


Kai WANG wrote:

I'm sorry that I still don't quite understand how to modify it. Could you please give a detailed explanation on the way to add a "sqrt" function please? For example, given the following simple program which has complile error, where should I add the "sqrt" function please?
Thanks very much for ur help!


typedef CGAL::Exact_predicates_exact_constructions_kernel K;
typedef K::Line_3            Line;
typedef K::Plane_3           Plane;
typedef K::Point_3           Point;
typedef K::Triangle_3        Triangle;

int main(void)
{
 std::list<Triangle> triangles;
 Point a(1.0,2.0,3.0);
 Point b(4.0,0.0,6.0);
 Point c(7.0,8.0,9.0);
 Point d(8.0,7.0,6.0);
 Point e(5.0,3.0,4.0);
 triangles.push_back(Triangle(a,b,c));
 triangles.push_back(Triangle(a,b,d));
 triangles.push_back(Triangle(d,e,c));

 Line line;
 Plane plane;

 // fit plane to whole triangles
 linear_least_squares_fitting_3(triangles.begin(),triangles.end(),plane,CGAL::Dimension_tag<2>());
  // fit line to triangle vertices
 linear_least_squares_fitting_3(triangles.begin(),triangles.end(),line, CGAL::Dimension_tag<0>());
  return 0;
}

On Thu, Oct 6, 2011 at 11:31 PM, Sebastien Loriot (GeometryFactory) < <mailto:>> wrote:

   the PCA package make use of the square root function, so the underlying
   number type in the kernel you are using should have a sqrt function
   available.

   Sebastien.



   kyewong wrote:

       Hi,
       When I'm using the linear_least_squares_fitting_3 and

       CGAL::Exact_predicates_exact___constructions_kernel as kernel,

       there will be a
       compile error as follows.
       Could anyone tell me how to modify it if I want to use both of
       them at the
       same time please? Thanks very much!

       1>F:\Program Files\CGAL-3.8\include\CGAL/__PCA_util.h(132) :

       error C2665:
       'sqrt' : none of the 3 overloads could convert all the argument
       types
       1>        F:\Program Files\Microsoft Visual Studio
       9.0\VC\include\math.h(581): could be 'long double sqrt(long double)'
       1>        F:\Program Files\Microsoft Visual Studio
       9.0\VC\include\math.h(533): or       'float sqrt(float)'
       1>        F:\Program Files\Microsoft Visual Studio
       9.0\VC\include\math.h(128): or       'double sqrt(double)'
       1>        while trying to match the argument list
       '(CGAL::Lazy_exact_nt<ET_>)'
       1>        with
       1>        [
       1>            ET_=CGAL::Gmpq
       1>        ]
       1>        F:\Program

       Files\CGAL-3.8\include\CGAL/__linear_least_squares_fitting___triangles_3.h(57)

       :
       see reference to function template instantiation 'void

       CGAL::internal::assemble___covariance_matrix_3&lt;__InputIterator,K&gt;(__InputIterator,InputIterator,__CGAL::Lazy_exact_nt<ET_>

       [],const CGAL::Point_3<R_> &,const K &,const
       CGAL::Triangle_3<R_> *,const
       CGAL::Dimension_tag<dim> &)' being compiled
       1>        with
       1>        [

       1>            InputIterator=std::list<__Triangle>::_Iterator<true>,

       1>            K=CGAL::Epeck,
       1>            ET_=CGAL::Gmpq,
       1>            R_=CGAL::Epeck,
       1>            dim=2
       1>        ]
       1>        F:\Program

       Files\CGAL-3.8\include\CGAL/__linear_least_squares_fitting___3.h(58)

       : see
       reference to function template instantiation
       'CGAL::Lazy_exact_nt<ET_>

       CGAL::internal::linear_least___squares_fitting_3&lt;__InputIterator,Kernel&gt;(__InputIterator,InputIterator,__CGAL::Plane_3<R_>

       &,CGAL::Point_3<R_> &,const CGAL::Triangle_3<R_> *,const K &,const
       CGAL::Dimension_tag<dim> &)' being compiled
       1>        with
       1>        [
       1>            ET_=CGAL::Gmpq,

       1>            InputIterator=std::list<__Triangle>::_Iterator<true>,

       1>            Kernel=CGAL::Epeck,
       1>            R_=CGAL::Epeck,
       1>            K=CGAL::Epeck,
       1>            dim=2
       1>        ]
       1>        F:\Program

       Files\CGAL-3.8\include\CGAL/__linear_least_squares_fitting___3.h(76)

       : see
       reference to function template instantiation
       'CGAL::Lazy_exact_nt<ET_>

       CGAL::linear_least_squares___fitting_3&lt;InputIterator,__Object,CGAL::Epeck,Tag&gt;(__InputIterator,InputIterator,__Object

       &,CGAL::Point_3<R_> &,const Tag &,const Kernel &)' being compiled
       1>        with
       1>        [
       1>            ET_=CGAL::Gmpq,

       1>            InputIterator=std::list<__Triangle>::_Iterator<true>,

       1>            Object=Plane,
       1>            Tag=CGAL::Dimension_tag<2>,
       1>            R_=CGAL::Epeck,
       1>            Kernel=CGAL::Epeck
       1>        ]
       1>        F:\Program

       Files\CGAL-3.8\include\CGAL/__linear_least_squares_fitting___3.h(93)

       : see
       reference to function template instantiation
       'CGAL::Lazy_exact_nt<ET_>

       CGAL::linear_least_squares___fitting_3&lt;InputIterator,__Object,CGAL::Point_3&lt;R_&gt;__,Tag>(InputIterator,__InputIterator,Object

       &,Point &,const Tag &)' being compiled
       1>        with
       1>        [
       1>            ET_=CGAL::Gmpq,

       1>            InputIterator=std::list<__Triangle>::_Iterator<true>,

       1>            Object=Plane,
       1>            R_=CGAL::Epeck,
       1>            Tag=CGAL::Dimension_tag<2>,

       1>            Point=CGAL::Point_3<CGAL::__Epeck>
       1>        ]
       1>        .\linear_least_squares___fitting_triangles_3.cpp(33) :

       see reference
       to function template instantiation 'CGAL::Lazy_exact_nt<ET_>

       CGAL::linear_least_squares___fitting_3&lt;std::list&lt;_Ty&__gt;::_Iterator<_Secure___validation>,Plane,CGAL::__Dimension_tag<dim>>(__InputIterator,InputIterator,__Object

       &,const Tag &)' being compiled
       1>        with
       1>        [
       1>            ET_=CGAL::Gmpq,
       1>            _Ty=Triangle,
       1>            _Secure_validation=true,
       1>            dim=2,

       1>            InputIterator=std::list<__Triangle>::_Iterator<true>,

       1>            Object=Plane,
       1>            Tag=CGAL::Dimension_tag<2>
       1>        ]

       --
       View this message in context:

       http://cgal-discuss.949826.n4.__nabble.com/compiling-error-of-__linear-least-squares-fitting-__3-under-Exact-predicates-__exact-constructions-kernel-__tp3878596p3878596.html

       <http://cgal-discuss.949826.n4.nabble.com/compiling-error-of-linear-least-squares-fitting-3-under-Exact-predicates-exact-constructions-kernel-tp3878596p3878596.html>
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Kai WANG

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