netgen/libsrc/meshing/basegeom.cpp

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#include <mystdlib.h>
#include "meshing.hpp"
namespace netgen
{
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DLL_HEADER GeometryRegisterArray geometryregister;
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//DLL_HEADER NgArray<GeometryRegister*> geometryregister;
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GeometryRegister :: ~GeometryRegister()
{ ; }
void GeometryFace :: RestrictHTrig(Mesh& mesh,
const PointGeomInfo& gi0,
const PointGeomInfo& gi1,
const PointGeomInfo& gi2,
const MeshingParameters& mparam,
int depth, double h) const
{
auto p0 = GetPoint(gi0);
auto p1 = GetPoint(gi1);
auto p2 = GetPoint(gi2);
auto longest = (p0-p1).Length();
int cutedge = 2;
if(auto len = (p0-p2).Length(); len > longest)
{
longest = len;
cutedge = 1;
}
if(auto len = (p1-p2).Length(); len > longest)
{
longest = len;
cutedge = 0;
}
PointGeomInfo gi_mid;
gi_mid.u = (gi0.u + gi1.u + gi2.u)/3;
gi_mid.v = (gi0.v + gi1.v + gi2.v)/3;
if(depth % 3 == 0)
{
double curvature = 0.;
curvature = max({curvature, GetCurvature(gi_mid),
GetCurvature(gi0), GetCurvature(gi1),
GetCurvature(gi2)});
if(curvature < 1e-3)
return;
double kappa = curvature * mparam.curvaturesafety;
h = mparam.maxh * kappa < 1 ? mparam.maxh : 1./kappa;
if(h < 1e-4 * longest)
return;
}
if(h < longest && depth < 10)
{
if(cutedge == 0)
{
PointGeomInfo gi_m;
gi_m.u = 0.5 * (gi1.u + gi2.u);
gi_m.v = 0.5 * (gi1.v + gi2.v);
RestrictHTrig(mesh, gi_m, gi2, gi0, mparam, depth+1, h);
RestrictHTrig(mesh, gi_m, gi0, gi1, mparam, depth+1, h);
}
else if(cutedge == 1)
{
PointGeomInfo gi_m;
gi_m.u = 0.5 * (gi0.u + gi2.u);
gi_m.v = 0.5 * (gi0.v + gi2.v);
RestrictHTrig(mesh, gi_m, gi1, gi2, mparam, depth+1, h);
RestrictHTrig(mesh, gi_m, gi0, gi1, mparam, depth+1, h);
}
else if(cutedge == 2)
{
PointGeomInfo gi_m;
gi_m.u = 0.5 * (gi0.u + gi1.u);
gi_m.v = 0.5 * (gi0.v + gi1.v);
RestrictHTrig(mesh, gi_m, gi1, gi2, mparam, depth+1, h);
RestrictHTrig(mesh, gi_m, gi2, gi0, mparam, depth+1, h);
}
}
else
{
auto pmid = GetPoint(gi_mid);
for(const auto& p : {p0, p1, p2, pmid})
mesh.RestrictLocalH(p, h);
}
}
struct Line
{
Point<3> p0, p1;
inline double Length() const { return (p1-p0).Length(); }
inline double Dist(const Line& other) const
{
Vec<3> n = p1-p0;
Vec<3> q = other.p1-other.p0;
double nq = n*q;
Point<3> p = p0 + 0.5*n;
double lambda = (p-other.p0)*n / (nq + 1e-10);
if (lambda >= 0 && lambda <= 1)
return (p-other.p0-lambda*q).Length();
return 1e99;
}
};
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void NetgenGeometry :: Analyse(Mesh& mesh,
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const MeshingParameters& mparam) const
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{
static Timer t1("SetLocalMeshsize"); RegionTimer regt(t1);
mesh.SetGlobalH(mparam.maxh);
mesh.SetMinimalH(mparam.minh);
mesh.SetLocalH(bounding_box.PMin(), bounding_box.PMax(),
mparam.grading);
// only set meshsize for edges longer than this
double mincurvelength = 1e-3 * bounding_box.Diam();
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if(mparam.uselocalh)
{
double eps = 1e-10 * bounding_box.Diam();
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const char* savetask = multithread.task;
multithread.task = "Analyse Edges";
// restrict meshsize on edges
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for(auto i : Range(edges))
{
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multithread.percent = 100. * i/edges.Size();
const auto & edge = edges[i];
auto length = edge->GetLength();
// skip very short edges
if(length < mincurvelength)
continue;
static constexpr int npts = 20;
// restrict mesh size based on edge length
for(auto i : Range(npts+1))
mesh.RestrictLocalH(edge->GetPoint(double(i)/npts), length/mparam.segmentsperedge);
// restrict mesh size based on edge curvature
double t = 0.;
auto p_old = edge->GetPoint(t);
while(t < 1.-eps)
{
t += edge->CalcStep(t, 1./mparam.curvaturesafety);
if(t < 1.)
{
auto p = edge->GetPoint(t);
auto dist = (p-p_old).Length();
mesh.RestrictLocalH(p, dist);
p_old = p;
}
}
}
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multithread.task = "Analyse Faces";
// restrict meshsize on faces
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for(auto i : Range(faces))
{
multithread.percent = 100. * i/faces.Size();
const auto& face = faces[i];
face->RestrictH(mesh, mparam);
}
if(mparam.closeedgefac.has_value())
{
multithread.task = "Analyse close edges";
constexpr int sections = 100;
Array<Line> lines;
lines.SetAllocSize(sections*edges.Size());
BoxTree<3> searchtree(bounding_box.PMin(),
bounding_box.PMax());
for(const auto& edge : edges)
{
if(edge->GetLength() < eps)
continue;
double t = 0.;
auto p_old = edge->GetPoint(t);
auto t_old = edge->GetTangent(t);
t_old.Normalize();
for(auto i : IntRange(1, sections+1))
{
t = double(i)/sections;
auto p_new = edge->GetPoint(t);
auto t_new = edge->GetTangent(t);
t_new.Normalize();
auto cosalpha = fabs(t_old * t_new);
if((i == sections) || (cosalpha < cos(10./180 * M_PI)))
{
auto index = lines.Append({p_old, p_new});
searchtree.Insert(p_old, p_new, index);
p_old = p_new;
t_old = t_new;
}
}
}
Array<int> linenums;
for(auto i : Range(lines))
{
const auto& line = lines[i];
if(line.Length() < eps) continue;
multithread.percent = 100.*i/lines.Size();
Box<3> box;
box.Set(line.p0);
box.Add(line.p1);
// box.Increase(max2(mesh.GetH(line.p0), mesh.GetH(line.p1)));
box.Increase(line.Length());
double mindist = 1e99;
linenums.SetSize0();
searchtree.GetIntersecting(box.PMin(), box.PMax(),
linenums);
for(auto num : linenums)
{
if(i == num) continue;
const auto & other = lines[num];
if((line.p0 - other.p0).Length2() < eps ||
(line.p0 - other.p1).Length2() < eps ||
(line.p1 - other.p0).Length2() < eps ||
(line.p1 - other.p1).Length2() < eps)
continue;
mindist = min2(mindist, line.Dist(other));
}
if(mindist == 1e99) continue;
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mindist /= *mparam.closeedgefac + 1e-10;
if(mindist < 1e-3 * bounding_box.Diam())
{
(*testout) << "extremely small local h: " << mindist
<< " --> setting to " << 1e-3 * bounding_box.Diam() << endl;
(*testout) << "somewhere near " << line.p0 << " - " << line.p1 << endl
;
mindist = 1e-3 * bounding_box.Diam();
}
mesh.RestrictLocalHLine(line.p0, line.p1, mindist);
}
}
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multithread.task = savetask;
}
for(const auto& mspnt : mparam.meshsize_points)
mesh.RestrictLocalH(mspnt.pnt, mspnt.h);
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mesh.LoadLocalMeshSize(mparam.meshsizefilename);
}
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void NetgenGeometry :: FindEdges(Mesh& mesh,
const MeshingParameters& mparam) const
{
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static Timer t1("MeshEdges"); RegionTimer regt(t1);
static Timer tdivide("Divide Edges");
static Timer tdivedgesections("Divide edge sections");
const char* savetask = multithread.task;
multithread.task = "Mesh Edges";
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// create face descriptors and set bc names
mesh.SetNBCNames(faces.Size());
for(auto i : Range(faces.Size()))
{
mesh.SetBCName(i, faces[i]->GetName());
// todo find attached solids
FaceDescriptor fd(i+1, 1, 0, i+1);
fd.SetBCName(mesh.GetBCNamePtr(i));
mesh.AddFaceDescriptor(fd);
}
std::map<size_t, PointIndex> vert2meshpt;
for(auto i : Range(vertices))
{
const auto& vert = *vertices[i];
MeshPoint mp(vert.GetPoint());
vert2meshpt[vert.GetHash()] = mesh.AddPoint(mp);
}
size_t segnr = 0;
for(auto facenr : Range(faces.Size()))
{
const auto& face = *faces[facenr];
for(auto facebndnr : Range(face.GetNBoundaries()))
{
auto boundary = face.GetBoundary(facebndnr);
for(auto enr : Range(boundary))
{
multithread.percent = 100. * ((double(enr)/boundary.Size() + facebndnr)/face.GetNBoundaries() + facenr)/faces.Size();
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const auto& oriented_edge = *boundary[enr];
auto edgenr = GetEdgeIndex(oriented_edge);
const auto& edge = edges[edgenr];
PointIndex startp, endp;
// throws if points are not found
startp = vert2meshpt.at(edge->GetStartVertex().GetHash());
endp = vert2meshpt.at(edge->GetEndVertex().GetHash());
// ignore collapsed edges
if(startp == endp && edge->GetLength() < 1e-10 * bounding_box.Diam())
continue;
Array<MeshPoint> mps;
Array<double> params;
// -------------------- DivideEdge -----------------
static constexpr size_t divide_edge_sections = 1000;
tdivide.Start();
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double hvalue[divide_edge_sections+1];
hvalue[0] = 0;
Point<3> old_pt = edge->GetPoint(0.);
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// calc local h for edge
tdivedgesections.Start();
for(auto i : Range(divide_edge_sections))
{
auto pt = edge->GetPoint(double(i+1)/divide_edge_sections);
hvalue[i+1] = hvalue[i] + 1./mesh.GetH(pt) * (pt-old_pt).Length();
old_pt = pt;
}
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int nsubedges = max2(1, int(floor(hvalue[divide_edge_sections]+0.5)));
tdivedgesections.Stop();
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mps.SetSize(nsubedges-1);
params.SetSize(nsubedges+1);
int i = 1;
int i1 = 0;
do
{
if (hvalue[i1]/hvalue[divide_edge_sections]*nsubedges >= i)
{
params[i] = (double(i1)/divide_edge_sections);
mps[i-1] = MeshPoint(edge->GetPoint(params[i]));
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i++;
}
i1++;
if (i1 > divide_edge_sections)
{
nsubedges = i;
mps.SetSize(nsubedges-1);
params.SetSize(nsubedges+1);
cout << "divide edge: local h too small" << endl;
}
} while(i < nsubedges);
params[0] = 0.;
params[nsubedges] = 1.;
if(params[nsubedges] <= params[nsubedges-1])
{
cout << "CORRECTED" << endl;
mps.SetSize (nsubedges-2);
params.SetSize (nsubedges);
params[nsubedges-1] = 1.;
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}
tdivide.Stop();
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// ----------- Add Points to mesh and create segments -----
Array<PointIndex> pnums(mps.Size() + 2);
pnums[0] = startp;
pnums[mps.Size()+1] = endp;
double eps = bounding_box.Diam() * 1e-8;
for(auto i : Range(mps))
{
bool exists = false;
for(auto pi : Range(mesh.Points()))
{
if((mesh[pi] - mps[i]).Length() < eps)
{
exists = true;
pnums[i+1] = pi;
break;
}
}
if(!exists)
pnums[i+1] = mesh.AddPoint(mps[i]);
}
for(auto i : Range(pnums.Size()-1))
{
segnr++;
Segment seg;
seg[0] = pnums[i];
seg[1] = pnums[i+1];
seg.edgenr = segnr;
seg.epgeominfo[0].dist = params[i];
seg.epgeominfo[1].dist = params[i+1];
seg.epgeominfo[0].edgenr = edgenr;
seg.epgeominfo[1].edgenr = edgenr;
seg.si = facenr+1;
seg.surfnr1 = facenr+1;
// TODO: implement functionality to transfer edge parameter t to face parameters u,v
for(auto j : Range(2))
face.CalcEdgePointGI(*edge, params[i+j],
seg.epgeominfo[j]);
if(!oriented_edge.OrientedLikeGlobal())
{
swap (seg[0], seg[1]);
swap (seg.epgeominfo[0].dist, seg.epgeominfo[1].dist);
swap (seg.epgeominfo[0].u, seg.epgeominfo[1].u);
swap (seg.epgeominfo[0].v, seg.epgeominfo[1].v);
}
mesh.AddSegment(seg);
}
}
}
}
mesh.CalcSurfacesOfNode();
multithread.task = savetask;
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}
void NetgenGeometry :: MeshSurface(Mesh& mesh,
const MeshingParameters& mparam) const
{
static Timer t1("Surface Meshing"); RegionTimer regt(t1);
const char* savetask = multithread.task;
multithread.task = "Mesh Surface";
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Array<int, PointIndex> glob2loc(mesh.GetNP());
for(auto k : Range(faces))
{
multithread.percent = 100. * k/faces.Size();
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const auto& face = *faces[k];
auto bb = face.GetBoundingBox();
bb.Increase(bb.Diam()/10);
Meshing2 meshing(*this, mparam, bb);
glob2loc = 0;
int cntp = 0;
for(auto& seg : mesh.LineSegments())
{
if(seg.si == k+1)
{
for(auto j : Range(2))
{
auto pi = seg[j];
if(glob2loc[pi] == 0)
{
meshing.AddPoint(mesh[pi], pi);
cntp++;
glob2loc[pi] = cntp;
}
}
}
}
for(auto & seg : mesh.LineSegments())
{
if(seg.si == k+1)
{
PointGeomInfo gi0, gi1;
gi0.trignum = gi1.trignum = k+1;
gi0.u = seg.epgeominfo[0].u;
gi0.v = seg.epgeominfo[0].v;
gi1.u = seg.epgeominfo[1].u;
gi1.v = seg.epgeominfo[1].v;
meshing.AddBoundaryElement(glob2loc[seg[0]],
glob2loc[seg[1]],
gi0, gi1);
}
}
// TODO Set max area 2* area of face
auto noldsurfels = mesh.GetNSE();
static Timer t("GenerateMesh"); RegionTimer reg(t);
MESHING2_RESULT res = meshing.GenerateMesh(mesh, mparam, mparam.maxh, k+1);
for(auto i : Range(noldsurfels, mesh.GetNSE()))
{
mesh.SurfaceElements()[i].SetIndex(k+1);
}
}
multithread.task = savetask;
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}
void NetgenGeometry :: OptimizeSurface(Mesh& mesh, const MeshingParameters& mparam) const
{
const auto savetask = multithread.task;
multithread.task = "Optimizing surface";
static Timer timer_opt2d("Optimization 2D");
RegionTimer reg(timer_opt2d);
auto meshopt = MeshOptimize2d(mesh);
for(auto i : Range(mparam.optsteps2d))
{
PrintMessage(3, "Optimization step ", i);
int innerstep = 0;
for(auto optstep : mparam.optimize2d)
{
multithread.percent = 100. * (double(innerstep++)/mparam.optimize2d.size() + i)/mparam.optsteps2d;
switch(optstep)
{
case 's':
meshopt.EdgeSwapping(0);
break;
case 'S':
meshopt.EdgeSwapping(1);
break;
case 'm':
meshopt.ImproveMesh(mparam);
break;
case 'c':
meshopt.CombineImprove();
break;
}
}
}
mesh.CalcSurfacesOfNode();
mesh.Compress();
multithread.task = savetask;
}
shared_ptr<NetgenGeometry> GeometryRegisterArray :: LoadFromMeshFile (istream & ist) const
{
for (int i = 0; i < Size(); i++)
{
NetgenGeometry * hgeom = (*this)[i]->LoadFromMeshFile (ist);
if (hgeom)
return shared_ptr<NetgenGeometry>(hgeom);
}
return nullptr;
}
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int NetgenGeometry :: GenerateMesh (shared_ptr<Mesh> & mesh, MeshingParameters & mparam)
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{
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multithread.percent = 0;
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if(mparam.perfstepsstart <= MESHCONST_ANALYSE)
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{
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if(!mesh)
mesh = make_shared<Mesh>();
mesh->geomtype = GetGeomType();
Analyse(*mesh, mparam);
}
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if(multithread.terminate || mparam.perfstepsend <= MESHCONST_ANALYSE)
return 0;
if(mparam.perfstepsstart <= MESHCONST_MESHEDGES)
FindEdges(*mesh, mparam);
if(multithread.terminate || mparam.perfstepsend <= MESHCONST_MESHEDGES)
return 0;
if (mparam.perfstepsstart <= MESHCONST_MESHSURFACE)
{
MeshSurface(*mesh, mparam);
mesh->CalcSurfacesOfNode();
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}
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if (multithread.terminate || mparam.perfstepsend <= MESHCONST_MESHSURFACE)
return 0;
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if (mparam.perfstepsstart <= MESHCONST_OPTSURFACE)
OptimizeSurface(*mesh, mparam);
if (multithread.terminate || mparam.perfstepsend <= MESHCONST_OPTSURFACE)
return 0;
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if(mparam.perfstepsstart <= MESHCONST_MESHVOLUME)
{
multithread.task = "Volume meshing";
MESHING3_RESULT res = MeshVolume (mparam, *mesh);
if (res != MESHING3_OK) return 1;
if (multithread.terminate) return 0;
RemoveIllegalElements (*mesh);
if (multithread.terminate) return 0;
MeshQuality3d (*mesh);
}
if (multithread.terminate || mparam.perfstepsend <= MESHCONST_MESHVOLUME)
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return 0;
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if (mparam.perfstepsstart <= MESHCONST_OPTVOLUME)
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{
multithread.task = "Volume optimization";
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OptimizeVolume (mparam, *mesh);
if (multithread.terminate) return 0;
}
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FinalizeMesh(*mesh);
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return 0;
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}
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void NetgenGeometry :: Save (string filename) const
{
throw NgException("Cannot save geometry - no geometry available");
}
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static RegisterClassForArchive<NetgenGeometry> regnggeo;
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}