> On 27 Oct 2018, at 00:16, Max Orok <[email protected]> wrote: > > Hi Thomas, > > I first tried to set the random factors using: > Mesh.RandomFactor = 1e-9; > Mesh.RandomFactor3D = 1e-9; > > I think the bug is elsewhere however... > With your file, I get a warning the first time and none the subsequent times. > I think it is due to internal state with the mesher remembering the choice of > MeshAdapt?
Yes : when meshing fails with Delaunay or Frontal we currently force MeshAdapt on that surface. Currently this choice is persistent (in a Gmsh run) - I will change this so that the initial state is restored. > Switching from Delauney to MeshAdapt halfway might cause different point > spacing etc. > > Here are some pictures showing the two consecutive mesh logs > > 1st time: > <image.png> > > 2nd time (same window): > <image.png> > > On closing Gmsh and trying again, this repeats. > > Instead, to fix your problem, you can set the meshing algo to MeshAdapt ahead > of time by changing the line here: > Mesh.Algorithm = 1; // changed to MeshAdapt > > Three repeated trials gave identical output files. > > p.s. just in case, all of the current / modified options can be looked > through and searched using Ctrl-Shift-H or Help -> Current Options and > Workspace > > Sincerely, > Max > > On Fri, Oct 26, 2018 at 12:44 PM, Thomas Kiel > <[email protected]> wrote: > Dear Gmshers, > > as I already pointed out in an earlier email (s. > http://onelab.info/pipermail/gmsh/2018/012045.html), I had problems with > reproducing the exact same mesh twice. Since this email was unfortunately > html encoded I think it was overlooked. Yet I like to apologize to ask again, > this time in text formatted email, how to set the random number generator > seed with an outside option? > > I know, that a grep to "srand" within the gmsh git repository gives several > times hard-coded initialized seeds, e.g. > > Geo/SOrientedBoundingBox.cpp:326: srand((unsigned)time(0)); > Mesh/Levy3D.cpp:624: srand(time(NULL)); > Mesh/Levy3D.cpp:1359: srand(time(NULL)); > Mesh/meshGFaceRecombine.cpp:245: srand(time(NULL)); > Mesh/meshGFaceLloyd.cpp:394: srand(time(NULL)); > > yet I am not sure whether these influence my mesh generation. A minimalistic > test file which causes different meshes at consecutive runs in my case, is > > > //+ > SetFactory("OpenCASCADE"); > > Mesh.CharacteristicLengthMin = 0.001; > Mesh.CharacteristicLengthMax = 2.0; > > Mesh.CharacteristicLengthExtendFromBoundary = 1; > > Mesh.Algorithm = 5; > Mesh.Smoothing = 3; > Mesh.Algorithm3D = 1; > > Box(1) = {0, -0.5, -0.5, 1, 1, 1}; > Box(2) = {-1, -0.5, -0.5, 1, 1, 1}; > Sphere(3) = {0.5, 0.0, 0.0, 0.3, -Pi/2, Pi/2, 2*Pi}; > > Coherence; > > surfs_box1() = Unique(Abs(Boundary{ Volume{4}; } )); > lines_box1() = Unique(Abs(Boundary{ Surface{surfs_box1()}; } )); > pts_box1() = Unique(Abs(Boundary{ Line{lines_box1()}; } )); > > surfs_sphere() = Unique(Abs(Boundary{ Volume{3}; } )); > lines_sphere() = Unique(Abs(Boundary{ Surface{surfs_sphere()}; } )); > pts_sphere() = Unique(Abs(Boundary{ Line{lines_sphere()}; } )); > > surfs_box2() = Unique(Abs(Boundary{ Volume{2}; } )); > lines_box2() = Unique(Abs(Boundary{ Surface{surfs_box2()}; } )); > pts_box2() = Unique(Abs(Boundary{ Line{lines_box2()}; } )); > > // sorted from largest to smallest: > Characteristic Length{pts_box2()} = 0.5; > Characteristic Length{pts_sphere()} = 0.2; > Characteristic Length{pts_box1()} = 0.1; > > > > I tested this on a machine running Ubuntu 16.04 and installed the > out-of-the-box gmsh 4.0.4 version from the webpage. If any further detail on > the running machine is required please tell me. > I hope you can help me out. > > Thanks a lot in advance and best regards, > > Thomas Kiel > > -- > Thomas Kiel > Theoretische Optik und Photonik > > Humboldt-Universität zu Berlin, Institut für Physik > Newtonstraße 15, 12489 Berlin > > Tel.: +49 30 2093 7999 > E-Mail: [email protected] > Web: https://top.physik.hu-berlin.de/people/thomas-kiel > > _______________________________________________ > gmsh mailing list > [email protected] > http://onelab.info/mailman/listinfo/gmsh > > > > -- > Max Orok > Contractor > www.mevex.com > > > _______________________________________________ > gmsh mailing list > [email protected] > http://onelab.info/mailman/listinfo/gmsh — Prof. Christophe Geuzaine University of Liege, Electrical Engineering and Computer Science http://www.montefiore.ulg.ac.be/~geuzaine Free software: http://gmsh.info | http://getdp.info | http://onelab.info _______________________________________________ gmsh mailing list [email protected] http://onelab.info/mailman/listinfo/gmsh
