CGAL users discussion list

[Ge Zhang <>]

Hi Alex,

 

Thank you very much for your answer. Changing

Point p(3, coord+i*3, coord+i*3+3);

to

                                Point p(coord[i*3], coord[i*3+1], coord[i*3+2]);

worked.

 

However, since I need to work in any dimensions later, I want to have a way to create Points in any dimensions. I read the webpage:

http://doc.cgal.org/latest/Kernel_d/classCGAL_1_1Point__d.html

 

and thought Point p(dim, coord+i*dim, coord+i*dim+dim); should be the dimension-independent way to do this. Could you tell me why it is not working for dim=3?

 

Best,

Ge

From: [mailto:] On Behalf Of Alex Vergara Gil
Sent: Tuesday, March 25, 2014 3:18 PM
To:
Subject: Re: [cgal-discuss] CGAL dD Delaunay Problem

 

Mainly because you have commited several bugs

--------------------------------------

instead of

Point p(3, coord+i*3, coord+i*3+3);

put

Point p(coord+i*3, coord+i*3+1, coord+i*3+2);

---------------------------------------

or you can redefine

double coord[] = {

as

Point coord[] = {

{15.987446522913068, 27.202164077804600, -1.7503256142623180},

... and so on

and instead of

Point p(3, coord+i*3, coord+i*3+3);

simply Point p = coord[i]

 

The two ways are equivalent

Regards

 

Alex

 

----- Original Message -----

From: Ge Zhang

To:

Sent: Tuesday, March 25, 2014 12:56 PM

Subject: [cgal-discuss] CGAL dD Delaunay Problem

 

Dear Sir or Madam,

 

I am not sure if I have made an error or if there is a bug in CGAL dD Delaunay package. I need to do Delaunay triangulation of some three-dimensional points and need to generalize the code to other dimensions later. So I wrote this code:

 

///////////////////////////////////////////////////////////////////////////

double coord[] = {

15.987446522913068, 27.202164077804600, -1.7503256142623180,

15.783731654803892, 27.268252018459251, -1.7667168014850418,

15.366332754158634, 25.364059942735178, -0.12067529139448278,

14.798358756496864, 25.645272186454374, -0.24621719891310628,

14.416741390968623, 26.534931393517535, -0.90761123478229566,

12.653889524424551, 30.356776464885129, 1.6780311801981169,

20.141382962264476, 29.666174471723380, 0.81578848925181291,

15.255480206458079, 32.065555891106911, 0.14008969527418605,

15.856413673274881, 31.537804468497811, -0.50108136475224174,

19.537758401022533, 29.790220202824923, -0.21754568768545338,

19.418171028905622, 29.790007422401796, -0.38830723957693186,

20.081590302704605, 29.854788525235321, 0.73931846754153374,

16.096713953744956, 24.603235225447076, 1.9663067370703267,

15.057336655250380, 24.912757478035189, 2.7258085800022718,

19.717425535978570, 27.248357239016887, 3.5216075631300305,

20.340124881568187, 28.287915509305925, 2.9881740318160834,

18.440406384399445, 28.756603149763084, 5.7274305773261025,

19.732584195169082, 29.437336063389296, 4.1695063361795697,

16.615174375063219, 32.278894713132360, 2.6796054812782928,

19.411374934889903, 30.874452428442833, 2.6765292926211286,

15.527857372851596, 31.342303101257738, 4.4163514428924291,

17.970992967584714, 28.796276720304878, 5.9574834972343362,

14.323514965294358, 26.455018287900284, 4.7555968341210084,

12.748877146187398, 30.055258023558022, 3.4117720135679241,

};

 

 

#include <CGAL/Cartesian_d.h>

#include <CGAL/Kernel_d/Sphere_d.h>

#include <CGAL/Delaunay_d.h>

#include <iostream>

#include <list>

 

typedef CGAL::Cartesian_d<double> Kernel;

typedef CGAL::Delaunay_d<Kernel> Delaunay;

typedef Delaunay::Vertex_handle Vertex_handle;

typedef Delaunay::Simplex_handle Simplex_handle;

typedef Delaunay::Point_d Point;

 

 

int main()

{

                Delaunay De(3);

                for(int i=0; i<24; i++)

                {

                                Point p(3, coord+i*3, coord+i*3+3);

                                De.insert(p);

                }

                std::list<Simplex_handle> simplices = De.all_simplices();

                std::cout<<simplices.size();

                return 0;

}

///////////////////////////////////////////////////////////////////////////

 

When I run this program on a Windows Server 2012 machine using Visual Studio 2012 compiler, the output I get is:

3

 

The problem is, if one plot the coordinates using MATLAB, one can clearly see that those points form a polygon and the Delaunay triangulation should consist of way more than 3 simplices. But why does the program only find 3 simplices?

 

Best,

Ge Zhang

 

 

 

 

 

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