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boundarylayer - some more fixes on growth vector interpolation

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mhochsteger@cerbsim.com 2022-03-01 20:18:05 +01:00
parent e8c9d8e1fc
commit 36440970fb
4 changed files with 147 additions and 77 deletions
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132
libsrc/meshing/boundarylayer.cpp
View File

@ -180,12 +180,12 @@ namespace netgen
}
}
void InterpolateSurfaceGrowthVectors(const Mesh & mesh, const BoundaryLayerParameters& blp, int fd_old, FlatArray<Vec<3>, PointIndex> growthvectors)
void InterpolateSurfaceGrowthVectors(const Mesh & mesh, const BoundaryLayerParameters& blp, int fd_old, FlatArray<Vec<3>, PointIndex> growthvectors, const Table<SurfaceElementIndex, PointIndex> & p2sel)
{
auto np = mesh.GetNP();
// interpolate growth vectors at inner surface points from surrounding edge points
Array<Point<2>, PointIndex> delaunay_points(mesh.GetNP());
Array<int, PointIndex> p2face(mesh.GetNP());
p2face = 0;
Array<Point<2>, PointIndex> delaunay_points(np);
Array<PointIndex, PointIndex> pmap(np); // maps duplicated points
Array<SurfaceElementIndex> surface_els;
Array<PointIndex> edge_points;
@ -195,33 +195,75 @@ namespace netgen
if(!blp.surfid.Contains(facei))
continue;
p2face = 0;
edge_points.SetSize(0);
surface_points.SetSize(0);
surface_els.SetSize(0);
delaunay_points.SetSize(np);
pmap.SetSize(np);
mesh.GetSurfaceElementsOfFace (facei, surface_els);
Box<2> bbox ( Box<2>::EMPTY_BOX );
for(auto sei : surface_els)
{
const auto & sel = mesh[sei];
auto sel = mesh[sei];
for (auto i : Range(sel.GetNP()))
{
auto pi = sel[i];
if(p2face[pi] != 0)
continue;
auto & gi = sel.GeomInfo()[i];
Point<2> p = {gi.u, gi.v};
bbox.Add(p);
}
}
p2face[pi] = facei;
BoxTree<2> tree(bbox);
for(auto pi : mesh.Points().Range())
{
auto n_surf_els = p2sel[pi].Size();
bool has_relevant_sel = false;
for(auto sei : p2sel[pi])
if(mesh[sei].GetIndex()==facei)
{
has_relevant_sel = true;
break;
}
if(!has_relevant_sel)
continue;
if(mesh[pi].Type() <= EDGEPOINT)
edge_points.Append(pi);
else
surface_points.Append(pi);
auto & gi = sel.GeomInfo()[i];
// TODO: project to plane if u,v not available?
delaunay_points[pi] = {gi.u, gi.v};
bbox.Add(delaunay_points[pi]);
// the same point might have different uv coordinates (closed edges for instance)
// duplicate these points for the delaunay tree
bool inserted = false;
for(auto sei : p2sel[pi])
{
auto sel = mesh[sei];
if(sel.GetIndex()!=facei)
continue;
PointGeomInfo gi = sel.GeomInfo()[sel.PNums().Pos(pi)];
Point<2> p = {gi.u, gi.v};
bool found = false;
tree.GetFirstIntersecting( p, p, [&] (const auto pi_found) { return found = true; });
if(found)
continue;
auto pi_new = pi;
if(inserted)
{
pi_new = delaunay_points.Append(p);
pmap.Append(pi);
edge_points.Append(pi_new);
}
else
{
delaunay_points[pi] = p;
pmap[pi] = pi;
}
tree.Insert(p, pi_new);
inserted = true;
}
}
@ -231,10 +273,7 @@ namespace netgen
DelaunayMesh dmesh( delaunay_points, bbox );
for(auto pi : edge_points)
{
p2face[pi] = 0;
dmesh.AddPoint(pi);
}
std::map<PointIndex, double> weights;
for(auto pi : surface_points)
@ -245,15 +284,13 @@ namespace netgen
auto n = 1./v.Length() * v;
for(auto & [pi_other, weight] : weights)
{
auto t = weight * growthvectors[pi_other];
// interpolate only the tangential part of the growth vector
auto t = weight * growthvectors[pmap[pi_other]];
t -= (t * n) * n;
v += t;
}
}
}
}
void GenerateBoundaryLayer(Mesh& mesh, const BoundaryLayerParameters& blp)
@ -277,21 +314,17 @@ namespace netgen
if(!blp.outside)
domains.Invert();
auto& meshtopo = mesh.GetTopology();
meshtopo.SetBuildVertex2Element(true);
mesh.UpdateTopology();
bool have_single_segments = HaveSingleSegments(mesh);
Array<Segment> segments;
if(have_single_segments)
{
segments = BuildSegments(mesh);
mesh.SetNextMajorTimeStamp();
mesh.UpdateTopology();
}
else
segments = mesh.LineSegments();
auto& meshtopo = mesh.GetTopology();
int np = mesh.GetNP();
int ne = mesh.GetNE();
int nse = mesh.GetNSE();
@ -339,15 +372,42 @@ namespace netgen
}
}
// mark points for remapping
for(const auto& sel : mesh.SurfaceElements())
const auto & p2sel = mesh.CreatePoint2SurfaceElementTable();
for(auto pi : mesh.Points().Range())
{
const auto & p = mesh[pi];
if(p.Type() == INNERPOINT)
continue;
std::map<int, Vec<3>> normals;
// calculate one normal vector per face (average with angles as weights for multiple surface elements within a face)
for(auto sei : p2sel[pi])
{
const auto & sel = mesh[sei];
auto facei = sel.GetIndex();
if(!blp.surfid.Contains(facei))
continue;
auto n = surfacefacs[sel.GetIndex()] * getSurfaceNormal(sel);
if(n.Length2() != 0.)
{
for(auto pi : sel.PNums())
{
int itrig = sel.PNums().Pos(pi);
itrig += sel.GetNP();
auto v0 = (mesh[sel.PNumMod(itrig+1)] - mesh[pi]).Normalize();
auto v1 = (mesh[sel.PNumMod(itrig-1)] - mesh[pi]).Normalize();
if(normals.count(facei)==0)
normals[facei] = {0.,0.,0.};
normals[facei] += acos(v0*v1)*n;
}
for(auto & [facei, n] : normals)
n *= 1.0/n.Length();
// combine normal vectors for each face to keep uniform distances
auto & np = growthvectors[pi];
for(auto & [facei, n] : normals)
{
if(np.Length() == 0) { np = n; continue; }
auto npn = np * n;
auto npnp = np * np;
@ -356,7 +416,6 @@ namespace netgen
np += (nn - npn)/(nn - npn*npn/npnp) * (n - npn/npnp * np);
}
}
}
// Bit array to keep track of segments already processed
BitArray segs_done(nseg+1);
@ -551,7 +610,7 @@ namespace netgen
}
if(interpolate_growth_vectors)
InterpolateSurfaceGrowthVectors(mesh, blp, fd_old, growthvectors);
InterpolateSurfaceGrowthVectors(mesh, blp, fd_old, growthvectors, p2sel);
// insert new points
for (PointIndex pi = 1; pi <= np; pi++)
@ -889,6 +948,7 @@ namespace netgen
}
mesh.GetTopology().ClearEdges();
mesh.UpdateTopology();
mesh.SetGeometry(nullptr);
}
void AddDirection( Vec<3> & a, Vec<3> b )

57
libsrc/meshing/delaunay2d.cpp
View File

@ -190,26 +190,7 @@ namespace netgen
if(definitive_overlapping_trig==-1)
{
Mesh m;
m.AddFaceDescriptor (FaceDescriptor (1, 1, 0, 0));
for(auto pi : points.Range())
m.AddPoint(P3(points[pi]));
for (DelaunayTrig & trig : trigs)
{
if (trig[0] < 0) continue;
Vec<3> n = Cross (P3(points[trig[1]])-P3(points[trig[0]]),
P3(points[trig[2]])-P3(points[trig[0]]));
if (n(2) < 0) Swap (trig[1], trig[2]);
Element2d el(trig[0], trig[1], trig[2]);
el.SetIndex (1);
m.AddSurfaceElement (el);
}
m.Compress();
m.AddPoint(P3(points[pi_new]));
m.Save("error.vol.gz");
// GetMesh(pi_new)->Save("error.vol.gz");
throw Exception("point not in any circle "+ ToString(pi_new));
}
@ -299,15 +280,18 @@ namespace netgen
auto pi_last = *points.Range().end()-3;
for(auto edge : edges)
{
auto v0 = points[edge[0]] - p;
auto v1 = points[edge[1]] - p;
v0.Normalize();
v1.Normalize();
double angle = acos(v0*v1);
for(PointIndex pi : {edge[0], edge[1]})
{
if(pi>=pi_last)
continue;
if(weights.count(pi))
continue;
double weight = 1.0/(eps+Dist(p, points[pi]));
double weight = angle/(eps+Dist(p, points[pi]));
sum += weight;
weights[pi] = weight;
weights[pi] += weight;
}
}
double isum = 1.0/sum;
@ -336,6 +320,31 @@ namespace netgen
tree->DeleteElement (j);
}
unique_ptr<Mesh> DelaunayMesh::GetMesh(PointIndex pi_new)
{
auto mesh = make_unique<Mesh>();
Mesh & m = *mesh;
m.AddFaceDescriptor (FaceDescriptor (1, 1, 0, 0));
for(auto pi : points.Range())
m.AddPoint(P3(points[pi]));
for (DelaunayTrig & trig : trigs)
{
if (trig[0] < 0) continue;
Vec<3> n = Cross (P3(points[trig[1]])-P3(points[trig[0]]),
P3(points[trig[2]])-P3(points[trig[0]]));
if (n(2) < 0) Swap (trig[1], trig[2]);
Element2d el(trig[0], trig[1], trig[2]);
el.SetIndex (1);
m.AddSurfaceElement (el);
}
m.Compress();
m.AddPoint(P3(points[pi_new]));
return mesh;
}
ostream & operator<< (ostream & ost, DelaunayTrig trig)
{
ost << trig[0] << "-" << trig[1] << "-" << trig[2] << endl;

2
libsrc/meshing/delaunay2d.hpp
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@ -68,7 +68,7 @@ namespace netgen
void CalcWeights( PointIndex pi_new, std::map<PointIndex, double> & weights );
void AddPoint( PointIndex pi_new );
Array<DelaunayTrig> & GetElements() { return trigs; }
unique_ptr<Mesh> GetMesh(PointIndex pi_new); // for debugging purposes
};
} // namespace netgen

1
libsrc/meshing/topology.hpp
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@ -186,6 +186,7 @@ public:
{ return vert2element[vnr]; }
void GetVertexSurfaceElements( int vnr, Array<SurfaceElementIndex>& elements ) const;
const auto & GetVertexSurfaceElements( ) const { return vert2surfelement; }
FlatArray<SurfaceElementIndex> GetVertexSurfaceElements(PointIndex vnr) const
{ return vert2surfelement[vnr]; }