> On 6 Sep 2017, at 17:44, Xin Liu <liu1...@purdue.edu> wrote:
>
> Dear all,
>
> I am using gmsh API to create a simple second order 2D mesh. The simplified
> codes are
>
>
> #include <stdio.h>
> #include "Gmsh.h"
> #include "GModel.h"
>
> int main(int argc, char **argv)
> {
> GmshInitialize(0, 0);
> GModel *m = new GModel();
>
> m->setFactory("Gmsh");
>
> GVertex *v1 = m->addVertex(0, 1, 0, 0.1);
> GVertex *v2 = m->addVertex(0, 2, 0, 0.1);
> GVertex *v3 = m->addVertex(0, 3, 0, 0.1);
> GVertex *v4 = m->addVertex(1, 3, 0, 0.1);
> GVertex *v5 = m->addVertex(1, 2, 0, 0.1);
> GVertex *v6 = m->addVertex(1, 1, 0, 0.1);
>
> std::vector<GEdge*> edges1;
> edges1.push_back(m->addLine(v1, v2));
> edges1.push_back(m->addLine(v2, v5));
> edges1.push_back(m->addLine(v5, v6));
> edges1.push_back(m->addLine(v6, v1));
>
> std::vector<GEdge*> edges2;
> edges2.push_back(m->addLine(v2, v3));
> edges2.push_back(m->addLine(v3, v4));
> edges2.push_back(m->addLine(v4, v5));
> edges2.push_back(m->addLine(v5, v2));
Here you just duplicated curve v2-v5 (with reverse orientation)... Hence the
duplicated vertices.
PS: note that this undocumented API will be replaced by a documented, much
simpler C API in future releases of Gmsh. For more info see
http://gitlab.onelab.info/gmsh/gmsh/issues/188
>
> std::vector<std::vector<GEdge*> > loop1;
> loop1.push_back(edges1);
>
> std::vector<std::vector<GEdge*> > loop2;
> loop2.push_back(edges2);
>
>
> GFace *f1 = m->addPlanarFace(loop1);
> f1->addPhysicalEntity(1);
> GFace *f2 = m->addPlanarFace(loop2);
> f2->addPhysicalEntity(2);
>
>
> m->mesh(2);
> m->setOrderN(2, 0, 0);
> m->writeSC("test.msh");
> delete m;
> GmshFinalize();
> }
>
> After running the codes, I opened the .msh file with Gmsh. Then, I found
> there are some repeated nodes at the interface of two surfaces (attachment1).
> However, if I use gmsh gui to create this model and mesh it, then this issue
> doesn't exist. Any suggestions or comments are great appreciate.
>
>
>
>
> Thanks
> Lambert
>
>
>
> <attachment1.jpg><test.msh>_______________________________________________
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--
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
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