HomologyComputation.cpp

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// Gmsh - Copyright (C) 1997-2022 C. Geuzaine, J.-F. Remacle
//
// See the LICENSE.txt file in the Gmsh root directory for license information.
// Please report all issues on https://gitlab.onelab.info/gmsh/gmsh/issues.
//
// Contributed by Matti Pellikka <matti.pellikka@microsoft.com>.
 
#include <stdlib.h>
#include <string>
#include <iostream>
#include <sstream>
#include "GmshGlobal.h"
#include "GmshConfig.h"
#include "GModel.h"
#include "Homology.h"
#include "HomologyComputation.h"
 
#if defined(HAVE_KBIPACK)
 
StringXNumber HomologyComputationOptions_Number[] = {
  {GMSH_FULLRC, "ComputeHomology", nullptr, 1.},
  {GMSH_FULLRC, "ComputeCohomology", nullptr, 0.},
  {GMSH_FULLRC, "HomologyPhysicalGroupsBegin", nullptr, -1.},
  {GMSH_FULLRC, "CohomologyPhysicalGroupsBegin", nullptr, -1.},
  {GMSH_FULLRC, "CreatePostProcessingViews", nullptr, 1.},
  {GMSH_FULLRC, "ReductionOmit", nullptr, 1.},
  {GMSH_FULLRC, "ReductionCombine", nullptr, 3.},
  {GMSH_FULLRC, "PostProcessSimplify", nullptr, 1.},
  {GMSH_FULLRC, "ReductionHeuristic", nullptr, 1.}};
 
StringXString HomologyComputationOptions_String[] = {
  {GMSH_FULLRC, "DomainPhysicalGroups", nullptr, ""},
  {GMSH_FULLRC, "SubdomainPhysicalGroups", nullptr, ""},
  {GMSH_FULLRC, "ReductionImmunePhysicalGroups", nullptr, ""},
  {GMSH_FULLRC, "DimensionOfChainsToSave", nullptr, "0, 1, 2, 3"},
  {GMSH_FULLRC, "Filename", nullptr, "homology.msh"}};
 
extern "C" {
GMSH_Plugin *GMSH_RegisterHomologyComputationPlugin()
{
  return new GMSH_HomologyComputationPlugin();
}
}
 
std::string GMSH_HomologyComputationPlugin::getHelp() const
{
  return "Plugin(HomologyComputation) computes representative chains "
         "of basis elements of (relative) homology and cohomology spaces.\n\n"
 
         "Define physical groups in order to specify the computation "
         "domain and the relative subdomain. Otherwise the whole mesh "
         "is the domain and the relative subdomain is empty. \n\n"
 
         "Plugin(HomologyComputation) creates new views, one for each "
         "basis element. The resulting basis chains of desired dimension "
         "together with the mesh are saved to the given file.";
}
 
int GMSH_HomologyComputationPlugin::getNbOptions() const
{
  return sizeof(HomologyComputationOptions_Number) / sizeof(StringXNumber);
}
 
StringXNumber *GMSH_HomologyComputationPlugin::getOption(int iopt)
{
  return &HomologyComputationOptions_Number[iopt];
}
 
int GMSH_HomologyComputationPlugin::getNbOptionsStr() const
{
  return sizeof(HomologyComputationOptions_String) / sizeof(StringXString);
}
 
StringXString *GMSH_HomologyComputationPlugin::getOptionStr(int iopt)
{
  return &HomologyComputationOptions_String[iopt];
}
 
bool GMSH_HomologyComputationPlugin::parseStringOpt(int stringOpt,
                                                    std::vector<int> &intList)
{
  std::string list = HomologyComputationOptions_String[stringOpt].def;
  intList.clear();
 
  int n;
  char a;
  std::istringstream ss(list);
  while(ss >> n) {
    intList.push_back(n);
    if(ss >> a) {
      if(a != ',') {
        Msg::Error("Unexpected character \'%c\' while parsing \'%s\'", a,
                   HomologyComputationOptions_String[stringOpt].str);
        return false;
      }
    }
  }
  return true;
}
 
PView *GMSH_HomologyComputationPlugin::execute(PView *v)
{
  std::string fileName = HomologyComputationOptions_String[4].def;
  int hom = (int)HomologyComputationOptions_Number[0].def;
  int coh = (int)HomologyComputationOptions_Number[1].def;
  int hompg = (int)HomologyComputationOptions_Number[2].def;
  int cohpg = (int)HomologyComputationOptions_Number[3].def;
  bool pviews = (bool)HomologyComputationOptions_Number[4].def;
  bool omit = (bool)HomologyComputationOptions_Number[5].def;
  int combine = (int)HomologyComputationOptions_Number[6].def;
  bool smoothen = (bool)HomologyComputationOptions_Number[7].def;
  int heuristic = (int)HomologyComputationOptions_Number[8].def;
 
  std::vector<int> domain;
  std::vector<int> subdomain;
  std::vector<int> imdomain;
  std::vector<int> dimsave;
  if(!parseStringOpt(0, domain)) return nullptr;
  if(!parseStringOpt(1, subdomain)) return nullptr;
  if(!parseStringOpt(2, imdomain)) return nullptr;
  if(!parseStringOpt(3, dimsave)) return nullptr;
 
  GModel *m = GModel::current();
 
  Homology *homology = new Homology(m, domain, subdomain, imdomain, true,
                                    combine, omit, smoothen, heuristic);
  homology->setFileName(fileName);
 
  if(hom != 0) homology->findHomologyBasis(dimsave);
  if(coh != 0) homology->findCohomologyBasis(dimsave);
 
  for(std::size_t i = 0; i < dimsave.size(); i++) {
    int dim = dimsave.at(i);
    if(dim > -1 && dim < 4 && hom != 0) {
      homology->addChainsToModel(dim, pviews, hompg);
      if(hompg != -1) hompg += homology->betti(dim);
    }
  }
  for(std::size_t i = 0; i < dimsave.size(); i++) {
    int dim = dimsave.at(i);
    if(dim > -1 && dim < 4 && coh != 0) {
      homology->addCochainsToModel(dim, pviews, cohpg);
      if(cohpg != -1) cohpg += homology->betti(dim);
    }
  }
 
  delete homology;
 
  return nullptr;
}
 
#endif