text: /*
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  /*! \file
   * \internal \brief
   * Declares gmx::internal::LocalAtomSetDataData.
   *
   * \author Christian Blau <cblau@gwdg.de>
   * \ingroup module_domdec
   */
  #include "gmxpre.h"
  
  #include "localatomsetdata.h"
  
  #include <algorithm>
  #include <numeric>
  
  #include "gromacs/domdec/ga2la.h"
  
  namespace gmx
  {
  
  namespace internal
  {
  
  /********************************************************************
   * LocalAtomSetData
   */
  
  LocalAtomSetData::LocalAtomSetData(ArrayRef<const index> globalIndex) :
      globalIndex_(globalIndex.begin(), globalIndex.end()),
      localIndex_(globalIndex.begin(), globalIndex.end())
  {
      collectiveIndex_.resize(localIndex_.size());
      std::iota(collectiveIndex_.begin(), collectiveIndex_.end(), 0);
  }
  
  void LocalAtomSetData::setLocalAndCollectiveIndices(const gmx_ga2la_t& ga2la)
  {
      /* Loop over all the atom indices of the set to check which ones are local.
       * cf. dd_make_local_group_indices in groupcoord.cpp
       */
      int numAtomsGlobal = globalIndex_.size();
  
      /* Clear vector without changing capacity,
       * because we expect the size of the vectors to vary little. */
      localIndex_.resize(0);
      collectiveIndex_.resize(0);
  
      for (int iCollective = 0; iCollective < numAtomsGlobal; iCollective++)
      {
          if (const int* iLocal = ga2la.findHome(globalIndex_[iCollective]))
          {
              /* Save the atoms index in the local atom numbers array */
              /* The atom with this index is a home atom. */
              localIndex_.push_back(*iLocal);
  
              /* Keep track of where this local atom belongs in the collective index array.
               * This is needed when reducing the local arrays to a collective/global array
               * in communicate_group_positions */
              collectiveIndex_.push_back(iCollective);
          }
      }
  }
  
  } // namespace internal
  
  } // namespace gmx
  