[Gmsh] a bug?

Christophe Geuzaine cgeuzaine at ulg.ac.be
Sun Aug 22 15:42:18 CEST 2010


On 22/04/10 06:06, Sean Hardesty wrote:
> I attach two meshes in the text: star1.geo, and star2.geo. I can't get
> gmsh 2.4.2 to do a 2D mesh of star1.geo; star2.geo is a simple
> modification that makes it work. Is this a bug, or is there some
> obvious reason that what I'm doing shouldn't work? This isn't
> important - just a curiosity I ran into when demoing gmsh to a friend.
>

Hi Sean - This was a very old bug, that we finally nailed :-) Give 
tomorrow's snapshot a try...

Thanks for the report!

>      Sean Hardesty
>
> /* star1.geo */
> lc = 0.04;
> r = 1/2*Sqrt( 1/5*( 5 - 2*Sqrt( 5 ) ) );
> R = Sqrt( 1/10 * ( 5 - Sqrt( 5 ) ) );
> Point(1) = {0,0,0,lc};
> Point(2) = {r*Cos( 0*2*Pi/5 + 2*Pi/10 ),r*Sin( 0*2*Pi/5 + 2*Pi/10 ),0,lc};
> Point(3) = {r*Cos( 1*2*Pi/5 + 2*Pi/10 ),r*Sin( 1*2*Pi/5 + 2*Pi/10 ),0,lc};
> Point(4) = {r*Cos( 2*2*Pi/5 + 2*Pi/10 ),r*Sin( 2*2*Pi/5 + 2*Pi/10 ),0,lc};
> Point(5) = {r*Cos( 3*2*Pi/5 + 2*Pi/10 ),r*Sin( 3*2*Pi/5 + 2*Pi/10 ),0,lc};
> Point(6) = {r*Cos( 4*2*Pi/5 + 2*Pi/10 ),r*Sin( 4*2*Pi/5 + 2*Pi/10 ),0,lc};
> Point(7) = {R*Cos( 0*2*Pi/5 + 2*Pi/10 ),R*Sin( 0*2*Pi/5  ),0,lc};
> Point(8) = {R*Cos( 1*2*Pi/5  ),R*Sin( 1*2*Pi/5  ),0,lc};
> Point(9) = {R*Cos( 2*2*Pi/5  ),R*Sin( 2*2*Pi/5  ),0,lc};
> Point(10) = {R*Cos( 3*2*Pi/5  ),R*Sin( 3*2*Pi/5  ),0,lc};
> Point(11) = {R*Cos( 4*2*Pi/5  ),R*Sin( 4*2*Pi/5  ),0,lc};
> Line(1) = {8,2};
> Line(2) = {2,7};
> Line(3) = {7,6};
> Line(4) = {6,11};
> Line(5) = {11,5};
> Line(6) = {5,10};
> Line(7) = {10,4};
> Line(8) = {4,9};
> Line(9) = {9,3};
> Line(10) = {3,8};
> Line Loop(11) = {1,2,3,4,5,6,7,8,9,10};
> Plane Surface(12) = {11};
>
> /* star2.geo */
> lc = 0.04;
> r = 1/2*Sqrt( 1/5*( 5 - 2*Sqrt( 5 ) ) );
> R = Sqrt( 1/10 * ( 5 - Sqrt( 5 ) ) );
> Point(1) = {0,0,0,lc};
> Point(2) = {r*Cos( 0*2*Pi/5 + 2*Pi/10 ),r*Sin( 0*2*Pi/5 + 2*Pi/10 ),0,lc};
> Point(3) = {r*Cos( 1*2*Pi/5 + 2*Pi/10 ),r*Sin( 1*2*Pi/5 + 2*Pi/10 ),0,lc};
> Point(4) = {r*Cos( 2*2*Pi/5 + 2*Pi/10 ),r*Sin( 2*2*Pi/5 + 2*Pi/10 ),0,lc};
> Point(5) = {r*Cos( 3*2*Pi/5 + 2*Pi/10 ),r*Sin( 3*2*Pi/5 + 2*Pi/10 ),0,lc};
> Point(6) = {r*Cos( 4*2*Pi/5 + 2*Pi/10 ),r*Sin( 4*2*Pi/5 + 2*Pi/10 ),0,lc};
> Point(7) = {R*Cos( 0*2*Pi/5 + 2*Pi/10 ),R*Sin( 0*2*Pi/5  ),0,lc};
> Point(8) = {R*Cos( 1*2*Pi/5  ),R*Sin( 1*2*Pi/5  ),0,lc};
> Point(9) = {R*Cos( 2*2*Pi/5  ),R*Sin( 2*2*Pi/5  ),0,lc};
> Point(10) = {R*Cos( 3*2*Pi/5  ),R*Sin( 3*2*Pi/5  ),0,lc};
> Point(11) = {R*Cos( 4*2*Pi/5  ),R*Sin( 4*2*Pi/5  ),0,lc};
> Line(1) = {8,2};
> Line(2) = {2,7};
> Line(3) = {7,6};
> Line(4) = {6,11};
> Line(5) = {11,5};
> Line(6) = {5,10};
> Line(7) = {10,4};
> Line(8) = {4,9};
> Line(9) = {9,3};
> Line(10) = {3,8};
> Line(11) = {2, 6};
> Line(12) = {6, 5};
> Line(13) = {5, 4};
> Line(14) = {4, 3};
> Line(15) = {3, 2};
> Line Loop(16) = {15, 11, 12, 13, 14};
> Plane Surface(17) = {16};
> Line Loop(18) = {1, -15, 10};
> Plane Surface(19) = {18};
> Line Loop(20) = {2, 3, -11};
> Plane Surface(21) = {20};
> Line Loop(22) = {4, 5, -12};
> Plane Surface(23) = {22};
> Line Loop(24) = {13, -7, -6};
> Plane Surface(25) = {24};
> Line Loop(26) = {14, -9, -8};
> Plane Surface(27) = {26};
>
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>
>


-- 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine