[Gmsh] BoundaryLayer: meshing of curves takes very long

[Christophe Geuzaine]

On 08 Jul 2013, at 21:55, Nico Schlömer <nico.schloemer at gmail.com> wrote:

> Hi all,
> 
> when meshing a domain that contains BoundarLayers, the meshing of the curves takes much longer then the meshing of the surfaces. Is there a way to speed this up?


Hi Nico - Decreasing the accuracy of the 1D integration will help:

gmsh -epslc1d 1e-3

(Or in a .geo file: Mesh.LcIntegrationPrecision=1e-3;)


> The following exampple highlights the problem:
> 
> ================== *snip* ==================
> Point(1) = {0, 0, 0};                                                           
> Point(2) = {1, 0, 0};                                                           
> Point(3) = {0, 1, 0};                                                           
>                                                                                 
> Line(1) = {1, 2};                                                               
> Line(2) = {2, 3};                                                               
> Line(3) = {3, 1};                                                               
>                                                                                 
> Line Loop(4) = {1, 2, 3};                                                       
> Plane Surface(5) = {4};                                                         
>                                                                                 
> Field[1] = BoundaryLayer;                                                       
> Field[1].EdgesList = {2};                                                       
> Field[1].hfar = 0.05;                                                           
> Field[1].hwall_n = 0.001;                                                       
> Field[1].hwall_t = 0.001;                                                       
> Field[1].ratio = 5.0;                                                           
> Field[1].thickness = 0.1;                                                       
> Field[1].AnisoMax = 100.0;                                                      
>                                                                                 
> Background Field = 1;
> ================== *snap* ==================
> 
> Output:
> 
> ================== *snip* ==================
> $ gmsh -2 boundary.geo 
> Info    : Running 'gmsh -2 boundary.geo' [Gmsh 2.6.2, 1 node, max. 4 threads]
> Info    : Started on Mon Jul  8 21:51:43 2013
> Info    : Reading 'boundary.geo'...
> Info    : Done reading 'boundary.geo'
> Info    : Meshing 1D...
> Info    : Meshing curve 1 (Line)
> Info    : 299998 points found in points clouds (1 edges)
> Info    : Meshing curve 2 (Line)
> Info    : Meshing curve 3 (Line)
> Info    : Done meshing 1D (10.516 s)
> Info    : Meshing 2D...
> Info    : Meshing surface 5 (Plane, Delaunay)
> Info    : Done meshing 2D (0.684 s)
> Info    : 11332 vertices 22665 elements
> Info    : Writing 'boundary.msh'...
> Info    : Done writing 'boundary.msh'
> Info    : Stopped on Mon Jul  8 21:51:55 2013
> ================== *snap* ==================
> 
> Cheers,
> Nico
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-- 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science 
http://www.montefiore.ulg.ac.be/~geuzaine