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Performance upgrades for mesh cracking
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@sebastiangrimberg
sebastiangrimberg committed Jun 20, 2024
1 parent 1fba894 commit cbcd40f
Showing 1 changed file with 79 additions and 51 deletions.
130 changes: 79 additions & 51 deletions palace/utils/geodata.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -6,11 +6,9 @@
#include <algorithm>
#include <array>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
Expand Down Expand Up @@ -1815,7 +1813,7 @@ void TransferHighOrderNodes(const mfem::Mesh &orig_mesh, mfem::Mesh &new_mesh,
// Transfer dofs from the old mesh to the new ones. Either consider all elements (works
// for orientation or numbering changes), or use the prescribed old to new element index
// map.
mfem::Array<int> vdofs, new_vdofs;
mfem::Array<int> vdofs;
mfem::Vector loc_vec;
for (int e = 0; e < orig_mesh.GetNE(); e++)
{
Expand All @@ -1824,8 +1822,8 @@ void TransferHighOrderNodes(const mfem::Mesh &orig_mesh, mfem::Mesh &new_mesh,
// No need for DofTransformation here since spaces are H1 or L2.
fespace->GetElementVDofs(e, vdofs);
nodes->GetSubVector(vdofs, loc_vec);
new_fespace->GetElementVDofs(!elem_delete_map ? e : (*elem_delete_map)[e], new_vdofs);
new_nodes->SetSubVector(new_vdofs, loc_vec);
new_fespace->GetElementVDofs(!elem_delete_map ? e : (*elem_delete_map)[e], vdofs);
new_nodes->SetSubVector(vdofs, loc_vec);
}
}
}
Expand Down Expand Up @@ -2087,7 +2085,6 @@ void SplitMeshElements(std::unique_ptr<mfem::Mesh> &orig_mesh, bool make_simplex
MFEM_VERIFY(
!element_types.has_pyramids,
"Splitting mesh elements to simplices does not support pyramid elements yet!");

if (preserve_curvature && mesh->GetNodes() && !orig_mesh_attr.Size())
{
BackUpAttributes(*mesh);
Expand Down Expand Up @@ -2364,12 +2361,12 @@ std::unordered_map<int, int> CheckMesh(const mfem::Mesh &mesh,
}

template <typename T>
class InterfaceRefinementMesh : public mfem::Mesh
class EdgeRefinementMesh : public mfem::Mesh
{
private:
// Container with keys being the vertex indicies (match row/column indices of v_to_v)
// of vertices lying on the interface to be refined.
const T &interface_vertices;
// Container with keys being pairs of vertex indicies (match row/column indices of v_to_v)
// of edges which we desire to be refined.
const T &refinement_edges;

void MarkTetMeshForRefinement(const mfem::DSTable &v_to_v) override
{
Expand All @@ -2380,14 +2377,13 @@ class InterfaceRefinementMesh : public mfem::Mesh
// after the marked elements are refined.
mfem::Array<mfem::real_t> lengths;
GetEdgeLengths2(v_to_v, lengths);
const auto min_length = 0.1 * lengths.Min();
const auto min_length = 0.01 * lengths.Min();
for (int i = 0; i < v_to_v.NumberOfRows(); i++)
{
bool has_i = (interface_vertices.find(i) != interface_vertices.end());
for (mfem::DSTable::RowIterator it(v_to_v, i); !it; ++it)
{
int j = it.Column();
if (!has_i || interface_vertices.find(j) == interface_vertices.end())
if (refinement_edges.find({i, j}) == refinement_edges.end())
{
// "Zero" the edge lengths which do not connect vertices on the interface. Avoid
// zero-length edges just in case.
Expand Down Expand Up @@ -2420,9 +2416,32 @@ class InterfaceRefinementMesh : public mfem::Mesh
}

public:
InterfaceRefinementMesh(mfem::Mesh &&mesh, const T &interface_vertices)
: mfem::Mesh(std::move(mesh)), interface_vertices(interface_vertices)
EdgeRefinementMesh(mfem::Mesh &&mesh, const T &refinement_edges)
: mfem::Mesh(std::move(mesh)), refinement_edges(refinement_edges)
{
}
};

template <typename T>
struct UnorderedPair
{
T first, second;
UnorderedPair(T first, T second) : first(first), second(second) {}
bool operator==(const UnorderedPair &v) const
{
return ((v.first == first && v.second == second) ||
(v.first == second && v.second == first));
}
};

template <typename T>
struct UnorderedPairHasher
{
std::size_t operator()(const UnorderedPair<T> &v) const
{
// Simple hash function for a pair, see https://tinyurl.com/2k4phapb.
return std::hash<T>()(std::min(v.first, v.second)) ^
std::hash<T>()(std::max(v.first, v.second)) << 1;
}
};

Expand Down Expand Up @@ -2563,7 +2582,7 @@ int AddInterfaceBdrElements(std::unique_ptr<mfem::Mesh> &orig_mesh,
// renumbering so is not saved. We still keep entries for non-duplicated crack
// vertices in the set to track them as processed, however.
auto &vert_components = crack_vert_duplicates.try_emplace(v).first->second;
for (auto it = components.begin() + 1; it != components.end(); it++)
for (auto it = components.begin() + 1; it != components.end(); ++it)
{
vert_components.emplace_back(-1, std::move(*it));
new_nv_dups++;
Expand All @@ -2579,8 +2598,8 @@ int AddInterfaceBdrElements(std::unique_ptr<mfem::Mesh> &orig_mesh,
// lying on the seam, but this doesn't catch all required cases.
if (refine_crack_elem)
{
std::map<std::pair<int, int>, std::vector<int>> coarse_crack_edge_to_be;
std::set<int> elem_to_refine;
std::unordered_map<UnorderedPair<int>, std::vector<int>, UnorderedPairHasher<int>>
coarse_crack_edge_to_be;
for (auto be : crack_bdr_elem)
{
const mfem::Element *bdr_el = orig_mesh->GetBdrElement(be);
Expand All @@ -2597,39 +2616,31 @@ int AddInterfaceBdrElements(std::unique_ptr<mfem::Mesh> &orig_mesh,
// This is a seam edge, so add the attached boundary element to a list. The
// check for the edge being interior to the crack is indicated by visiting more
// than once.
if (v1 < v0)
{
std::swap(v0, v1);
}
const auto key = std::make_pair(v0, v1);
auto it = coarse_crack_edge_to_be.find(key);
auto &bdr_elem_to_refine =
auto it = coarse_crack_edge_to_be.find({v0, v1});
auto &adjacent_be =
(it == coarse_crack_edge_to_be.end())
? coarse_crack_edge_to_be.try_emplace(key).first->second
? coarse_crack_edge_to_be.try_emplace({v0, v1}).first->second
: it->second;
bdr_elem_to_refine.push_back(be);
adjacent_be.push_back(be);
}
}
}
for (const auto &[edge, bdr_elem_to_refine] : coarse_crack_edge_to_be)
for (auto it = coarse_crack_edge_to_be.begin(); it != coarse_crack_edge_to_be.end();)
{
if (bdr_elem_to_refine.size() > 1)
// Remove all seam edges which are on the "outside" of the crack (visited only
// once).
if (it->second.size() == 1)
{
for (auto be : bdr_elem_to_refine)
{
int f, o, e1, e2;
orig_mesh->GetBdrElementFace(be, &f, &o);
orig_mesh->GetFaceElements(f, &e1, &e2);
MFEM_ASSERT(e1 >= 0 && e2 >= 0,
"Invalid internal boundary element connectivity!");
elem_to_refine.insert(e1);
elem_to_refine.insert(e2);
}
it = coarse_crack_edge_to_be.erase(it);
}
else
{
++it;
}
}
static int new_ne_ref = 0;
static int new_ref_its = 0;
if (!elem_to_refine.empty())
if (!coarse_crack_edge_to_be.empty())
{
// Locally refine the mesh using conformal refinement. If necessary, convert the
// mesh to simplices first to enable conforming refinement (this will do nothing
Expand All @@ -2646,13 +2657,29 @@ int AddInterfaceBdrElements(std::unique_ptr<mfem::Mesh> &orig_mesh,
face_to_be.clear();
return 0; // Mesh was converted to simplices, start over
}
std::unordered_map<int, int> elem_to_refine;
for (const auto &[edge, adjacent_be] : coarse_crack_edge_to_be)
{
for (auto be : adjacent_be)
{
int f, o, e1, e2;
orig_mesh->GetBdrElementFace(be, &f, &o);
orig_mesh->GetFaceElements(f, &e1, &e2);
MFEM_ASSERT(e1 >= 0 && e2 >= 0,
"Invalid internal boundary element connectivity!");
elem_to_refine[e1]++; // Value-initialized to 0 at first access
elem_to_refine[e2]++;
}
}
mfem::Array<mfem::Refinement> refinements;
refinements.Reserve(elem_to_refine.size());
for (auto e : elem_to_refine)
for (const auto &[e, count] : elem_to_refine)
{
// Tetrahedral bisection (vs. default octasection) will result in fewer added
// elements at the cost of a potential minor mesh quality degredation.
refinements.Append(mfem::Refinement(e, mfem::Refinement::X));
// refinements.Append(mfem::Refinement(e, (count > 1) ? mfem::Refinement::XY
// : mfem::Refinement::X));
}
if (mesh::CheckElements(*orig_mesh).has_simplices)
{
Expand All @@ -2665,7 +2692,7 @@ int AddInterfaceBdrElements(std::unique_ptr<mfem::Mesh> &orig_mesh,
// mesh every time to ensure multiple rounds of refinement target the interior
// boundary (we don't care about preserving the refinement hierarchy).
constexpr bool refine = true, fix_orientation = false;
InterfaceRefinementMesh ref_mesh(std::move(*orig_mesh), crack_vert_duplicates);
EdgeRefinementMesh ref_mesh(std::move(*orig_mesh), coarse_crack_edge_to_be);
ref_mesh.Finalize(refine, fix_orientation);
*orig_mesh = std::move(ref_mesh);
}
Expand Down Expand Up @@ -2917,8 +2944,9 @@ int AddInterfaceBdrElements(std::unique_ptr<mfem::Mesh> &orig_mesh,
b = 0;
}
MFEM_VERIFY(a + b > 0, "Invalid new boundary element attribute!");
int new_attr =
bdr_attr_max + (((a + b) * (a + b + 1)) / 2) + a; // At least bdr_attr_max + 1
long long int l_new_attr =
bdr_attr_max + (((a + b) * (long long int)(a + b + 1)) / 2) + a;
int new_attr = mfem::internal::to_int(l_new_attr); // At least bdr_attr_max + 1

// Add the boundary elements with the new boundary attribute. The element vertices
// may have been renumbered in the new mesh, so the new face is not necessarily
Expand All @@ -2944,6 +2972,12 @@ int AddInterfaceBdrElements(std::unique_ptr<mfem::Mesh> &orig_mesh,
bdr_el->GetVertices()[j] = el->GetVertices()[el->GetFaceVertices(i)[j]];
}
new_mesh->AddBdrElement(bdr_el);
if constexpr (false)
{
Mpi::Print(
"Adding boundary element with attribute {:d} from elements {:d} and {:d}\n",
new_attr, a, b);
}
if (new_face_bdr_elem[f] > 1)
{
// Flip order of vertices to reverse normal direction of the second added element.
Expand All @@ -2953,17 +2987,11 @@ int AddInterfaceBdrElements(std::unique_ptr<mfem::Mesh> &orig_mesh,
new_mesh->AddBdrElement(bdr_el);
if constexpr (false)
{
Mpi::Print("Adding two boundary elements with attribute {:d} from elements "
Mpi::Print("Adding second boundary element with attribute {:d} from elements "
"{:d} and {:d}\n",
new_attr, a, b);
}
}
else if constexpr (false)
{
Mpi::Print("Adding boundary element with attribute {:d} from elements "
"{:d} and {:d}\n",
new_attr, a, b);
}
}
}
}
Expand Down

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