tetrahedron.cpp

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// Copyright (c) 2010-2022, Lawrence Livermore National Security, LLC. Produced
// at the Lawrence Livermore National Laboratory. All Rights reserved. See files
// LICENSE and NOTICE for details. LLNL-CODE-806117.
//
// This file is part of the MFEM library. For more information and source code
// availability visit https://mfem.org.
//
// MFEM is free software; you can redistribute it and/or modify it under the
// terms of the BSD-3 license. We welcome feedback and contributions, see file
// CONTRIBUTING.md for details.

// Implementation of class Tetrahedron

#include "mesh_headers.hpp"

namespace mfem
{

Tetrahedron::Tetrahedron(const int *ind, int attr)
   : Element(Geometry::TETRAHEDRON)
{
   attribute = attr;
   for (int i = 0; i < 4; i++)
   {
      indices[i] = ind[i];
   }
   refinement_flag = 0;
   transform = 0;
}

Tetrahedron::Tetrahedron(int ind1, int ind2, int ind3, int ind4, int attr)
   : Element(Geometry::TETRAHEDRON)
{
   attribute  = attr;
   indices[0] = ind1;
   indices[1] = ind2;
   indices[2] = ind3;
   indices[3] = ind4;
   refinement_flag = 0;
   transform = 0;
}

void Tetrahedron::Init(int ind1, int ind2, int ind3, int ind4, int attr,
                       int ref_flag)
{
   attribute  = attr;
   indices[0] = ind1;
   indices[1] = ind2;
   indices[2] = ind3;
   indices[3] = ind4;
   refinement_flag = ref_flag;
   transform = 0;
}

void Tetrahedron::ParseRefinementFlag(int refinement_edges[2], int &type,
                                      int &flag)
{
   int i, f = refinement_flag;

   MFEM_VERIFY(f != 0, "tetrahedron is not marked");

   for (i = 0; i < 2; i++)
   {
      refinement_edges[i] = f & 7;
      f = f >> 3;
   }
   type = f & 7;
   flag = (f >> 3);
}

void Tetrahedron::CreateRefinementFlag(int refinement_edges[2], int type,
                                       int flag)
{
   // Check for correct type
#ifdef MFEM_DEBUG
   int e1, e2;
   e1 = refinement_edges[0];
   e2 = refinement_edges[1];
   // if (e1 > e2)  e1 = e2, e2 = refinement_edges[0];
   switch (type)
   {
      case Tetrahedron::TYPE_PU:
         if (e1 == 2 && e2 == 1) { break; }
         // if (e1 == 3 && e2 == 4) break;
         mfem_error("Error in Tetrahedron::CreateRefinementFlag(...) #1");
         break;
      case Tetrahedron::TYPE_A:
         if (e1 == 3 && e2 == 1) { break; }
         if (e1 == 2 && e2 == 4) { break; }
         // if (flag == 0)  // flag is assumed to be the generation
         //   if (e2 == 5)
         //      if (e1 >= 1 && e1 <= 5) break; // type is actually O or M
         //                                     //   ==>  ok for generation = 0
         mfem_error("Error in Tetrahedron::CreateRefinementFlag(...) #2");
         break;
      case Tetrahedron::TYPE_PF:
         if (flag > 0)  // PF is ok only for generation > 0
         {
            if (e1 == 2 && e2 == 1) { break; }
            // if (e1 == 3 && e2 == 4) break;
         }
         mfem_error("Error in Tetrahedron::CreateRefinementFlag(...) #3");
         break;
      case Tetrahedron::TYPE_O:
         if (flag == 0 && e1 == 5 && e2 == 5)
         {
            break;
         }
         mfem_error("Error in Tetrahedron::CreateRefinementFlag(...) #4");
         break;
      case Tetrahedron::TYPE_M:
         if (flag == 0)
         {
            if (e1 == 5 && e2 == 1) { break; }
            if (e1 == 2 && e2 == 5) { break; }
         }
         mfem_error("Error in Tetrahedron::CreateRefinementFlag(...) #5");
         break;
      default:
         mfem_error("Error in Tetrahedron::CreateRefinementFlag(...) #6");
         break;
   }
#endif

   refinement_flag = flag;
   refinement_flag <<= 3;

   refinement_flag |= type;
   refinement_flag <<= 3;

   refinement_flag |= refinement_edges[1];
   refinement_flag <<= 3;

   refinement_flag |= refinement_edges[0];
}

void Tetrahedron::GetMarkedFace(const int face, int *fv)
{
   int re[2], type, flag, *tv = this->indices;
   ParseRefinementFlag(re, type, flag);
   switch (face)
   {
      case 0:
         switch (re[1])
         {
            case 1: fv[0] = tv[1]; fv[1] = tv[2]; fv[2] = tv[3]; break;
            case 4: fv[0] = tv[3]; fv[1] = tv[1]; fv[2] = tv[2]; break;
            case 5: fv[0] = tv[2]; fv[1] = tv[3]; fv[2] = tv[1]; break;
         }
         break;
      case 1:
         switch (re[0])
         {
            case 2: fv[0] = tv[2]; fv[1] = tv[0]; fv[2] = tv[3]; break;
            case 3: fv[0] = tv[0]; fv[1] = tv[3]; fv[2] = tv[2]; break;
            case 5: fv[0] = tv[3]; fv[1] = tv[2]; fv[2] = tv[0]; break;
         }
         break;
      case 2:
         fv[0] = tv[0]; fv[1] = tv[1]; fv[2] = tv[3];
         break;
      case 3:
         fv[0] = tv[1]; fv[1] = tv[0]; fv[2] = tv[2];
         break;
   }
}

int Tetrahedron::NeedRefinement(HashTable<Hashed2> &v_to_v) const
{
   if (v_to_v.FindId(indices[0], indices[1]) != -1) { return 1; }
   if (v_to_v.FindId(indices[1], indices[2]) != -1) { return 1; }
   if (v_to_v.FindId(indices[2], indices[0]) != -1) { return 1; }
   if (v_to_v.FindId(indices[0], indices[3]) != -1) { return 1; }
   if (v_to_v.FindId(indices[1], indices[3]) != -1) { return 1; }
   if (v_to_v.FindId(indices[2], indices[3]) != -1) { return 1; }
   return 0;
}

void Tetrahedron::SetVertices(const int *ind)
{
   for (int i = 0; i < 4; i++)
   {
      indices[i] = ind[i];
   }
}

void Tetrahedron::MarkEdge(const DSTable &v_to_v, const int *length)
{
   int ind[4], i, j, l, L, type;

   // determine the longest edge
   L = length[v_to_v(indices[0], indices[1])]; j = 0;
   if ((l = length[v_to_v(indices[1], indices[2])]) > L) { L = l; j = 1; }
   if ((l = length[v_to_v(indices[2], indices[0])]) > L) { L = l; j = 2; }
   if ((l = length[v_to_v(indices[0], indices[3])]) > L) { L = l; j = 3; }
   if ((l = length[v_to_v(indices[1], indices[3])]) > L) { L = l; j = 4; }
   if ((l = length[v_to_v(indices[2], indices[3])]) > L) { j = 5; }

   for (i = 0; i < 4; i++)
   {
      ind[i] = indices[i];
   }

   switch (j)
   {
      case 1:
         indices[0] = ind[1]; indices[1] = ind[2];
         indices[2] = ind[0]; indices[3] = ind[3];
         break;
      case 2:
         indices[0] = ind[2]; indices[1] = ind[0];
         indices[2] = ind[1]; indices[3] = ind[3];
         break;
      case 3:
         indices[0] = ind[3]; indices[1] = ind[0];
         indices[2] = ind[2]; indices[3] = ind[1];
         break;
      case 4:
         indices[0] = ind[1]; indices[1] = ind[3];
         indices[2] = ind[2]; indices[3] = ind[0];
         break;
      case 5:
         indices[0] = ind[2]; indices[1] = ind[3];
         indices[2] = ind[0]; indices[3] = ind[1];
         break;
   }

   // Determine the two longest edges for the other two faces and
   // store them in ind[0] and ind[1]
   ind[0] = 2; ind[1] = 1;
   L = length[v_to_v(indices[0], indices[2])];
   if ((l = length[v_to_v(indices[0], indices[3])]) > L) { L = l; ind[0] = 3; }
   if ((l = length[v_to_v(indices[2], indices[3])]) > L) { ind[0] = 5; }

   L = length[v_to_v(indices[1], indices[2])];
   if ((l = length[v_to_v(indices[1], indices[3])]) > L) { L = l; ind[1] = 4; }
   if ((l = length[v_to_v(indices[2], indices[3])]) > L) { ind[1] = 5; }

   j = 0;
   switch (ind[0])
   {
      case 2:
         switch (ind[1])
         {
            case 1:  type = Tetrahedron::TYPE_PU; break;
            case 4:  type = Tetrahedron::TYPE_A;  break;
            case 5:
            default: type = Tetrahedron::TYPE_M;
         }
         break;
      case 3:
         switch (ind[1])
         {
            case 1:  type = Tetrahedron::TYPE_A;  break;
            case 4:  type = Tetrahedron::TYPE_PU;
               j = 1; ind[0] = 2; ind[1] = 1; break;
            case 5:
            default: type = Tetrahedron::TYPE_M;
               j = 1; ind[0] = 5; ind[1] = 1;
         }
         break;
      case 5:
      default:
         switch (ind[1])
         {
            case 1:  type = Tetrahedron::TYPE_M;  break;
            case 4:  type = Tetrahedron::TYPE_M;
               j = 1; ind[0] = 2; ind[1] = 5; break;
            case 5:
            default: type = Tetrahedron::TYPE_O;
         }
   }

   if (j)
   {
      mfem::Swap(indices[0], indices[1]);
      mfem::Swap(indices[2], indices[3]);
   }

   CreateRefinementFlag(ind, type);
}

// static method
void Tetrahedron::GetPointMatrix(unsigned transform, DenseMatrix &pm)
{
   double *a = &pm(0,0), *b = &pm(0,1), *c = &pm(0,2), *d = &pm(0,3);

   // initialize to identity
   a[0] = 0.0, a[1] = 0.0, a[2] = 0.0;
   b[0] = 1.0, b[1] = 0.0, b[2] = 0.0;
   c[0] = 0.0, c[1] = 1.0, c[2] = 0.0;
   d[0] = 0.0, d[1] = 0.0, d[2] = 1.0;

   int chain[12], n = 0;
   while (transform)
   {
      chain[n++] = (transform & 7) - 1;
      transform >>= 3;
   }

   /* The transformations and orientations here match the six cases in
      Mesh::Bisection for tetrahedra. */
   while (n)
   {
#define ASGN(a, b) (a[0] = b[0], a[1] = b[1], a[2] = b[2])
#define SWAP(a, b) for (int i = 0; i < 3; i++) { std::swap(a[i], b[i]); }
#define AVG(a, b, c) for (int i = 0; i < 3; i++) { a[i] = (b[i]+c[i])*0.5; }

      double e[3];
      AVG(e, a, b);
      switch (chain[--n])
      {
         case 0: ASGN(b, c); ASGN(c, d); break;
         case 1: ASGN(a, c); ASGN(c, d); break;
         case 2: ASGN(b, a); ASGN(a, d); break;
         case 3: ASGN(a, b); ASGN(b, d); break;
         case 4: SWAP(a, c); ASGN(b, d); break;
         case 5: SWAP(b, c); ASGN(a, d); break;
         default:
            MFEM_ABORT("Invalid transform.");
      }
      ASGN(d, e);
   }
}

void Tetrahedron::GetVertices(Array<int> &v) const
{
   v.SetSize(4);
   for (int i = 0; i < 4; i++)
   {
      v[i] = indices[i];
   }
}

Element *Tetrahedron::Duplicate(Mesh *m) const
{
#ifdef MFEM_USE_MEMALLOC
   Tetrahedron *tet = m->TetMemory.Alloc();
#else
   Tetrahedron *tet = new Tetrahedron;
#endif
   tet->SetVertices(indices);
   tet->SetAttribute(attribute);
   tet->SetRefinementFlag(refinement_flag);
   return tet;
}

}