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["Sebastien Loriot (GeometryFactory)" <>]

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 wrote:
> It is working after inserting following two lines.
> CGAL::Random default_random;
> CGAL::Random rnd = default_random;
>
> But why 'Random_points_on_sphere_3' always returns the points inside a sphere 
> not onside ??

I guess the points are not on the sphere because you are using a
floating point number type (see http://www.cgal.org/FAQ.html#inexact_NT)

Unfortunately, if you need to have points that are exactly on a sphere
you need to use a number type able to handle square roots exactly.

You may try CORE::Expr that directly handle square root exactly or
have a look at Sqrt_extension (which represents algebraic number of
degree 2).
http://www.cgal.org/Manual/beta/doc_html/cgal_manual/NumberTypeSupport_ref/Class_Sqrt_extension.html


Note that I think CORE::Expr should work directly with the random point
generator, while for Sqrt_extension it may require some modifications in
the generator.

S.


> <quote author='Sebastien Loriot (GeometryFactory)'>
> It is hard to answer to a question without seeing a line of your code.
>
> Anyway, this is working on my machine with CGAL 3.7 beta1
>
> #include <CGAL/Simple_cartesian.h>
> #include <CGAL/point_generators_3.h>
> #include <CGAL/random_selection.h>
>
> typedef CGAL::Simple_cartesian<double>     Kernel;
> typedef Kernel::Point_3                    Point_3;
> typedef CGAL::Creator_uniform_3<double,Point_3>  Creator;
>
> int main()
> {
>    CGAL::Random_points_on_sphere_3<Point_3,Creator>      g( 100.0);
>    return 0;
> }
>
>
>
>
> sbdk11 wrote:
> > Why I am getting following errors for the line
> > CGAL::Random_points_on_sphere_3<Point_3,Creator> g(20,Random&
> > rnd=default_random);
> >
> >
> > /cpp/test1/test3.cpp: In function ‘int main()’:
> > /cpp/test1/test3.cpp:75: error: ‘Random’ was not declared in this scope
> > /cpp/test1/test3.cpp:75: error: ‘rnd’ was not declared in this scope
> > /cpp/test1/test3.cpp:75: error: ‘default_random’ was not declared in this
> > scope