src/gromacs/domdec/localatomset.h

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  35 /*! \file
  36  * \libinternal \brief
  37  * Declares gmx::LocalAtomSet.
  38  *
  39  * \author Christian Blau <cblau@gwdg.de>
  40  * \inlibraryapi
  41  * \ingroup module_domdec
  42  */
  43 #ifndef GMX_DOMDEC_LOCALATOMSET_H
  44 #define GMX_DOMDEC_LOCALATOMSET_H
  45
  46 #include "gromacs/utility/arrayref.h"
  47
  48 namespace gmx
  49 {
  50
  51 namespace internal
  52 {
  53 class LocalAtomSetData;
  54 }   // namespace internal
  55 /*! \libinternal \brief
  56  * A local atom set collects local, global and collective indices of
  57  * the home atoms on a rank. The indices of the home atoms are automatically
  58  * updated during domain decomposition, thus gmx::LocalAtomSet::localIndex
  59  * enables iteration over local atoms properties like coordinates or forces.
  60  * TODO: add a LocalAtomSet iterator.
  61  *
  62  * To generate a LocalAtomSet call gmx::LocalAtomSetManger::add and keep the
  63  * handle to the LocalAtomSet returned from this call.
  64  *
  65  * \inlibraryapi
  66  * \ingroup module_domdec
  67  */
  68 class LocalAtomSet
  69 {
  70     public:
  71         friend class LocalAtomSetManager;
  72         /*! \brief Maps indices on rank [0..numAtomsLocal_) to global atom indicices.
  73          *
  74          * \returns the collective index.
  75          */
  76         ArrayRef<const int> collectiveIndex() const;
  77         /*! \brief Global indices of the atoms in this set.
  78          *
  79          * \note For best performance, store and use a local copy of the arrayref.
  80          *
  81          * \returns the global index.
  82          */
  83         ArrayRef<const int> globalIndex() const;
  84         /*! \brief Local indices of the atoms.
  85          *
  86          * For example, the i-th local atom coordinate of this set is
  87          * x[atomSet.localIndex()[i]].
  88          *
  89          * When using in a loop other than a range-based for loop,
  90          * performance may improve if the ArrayRef is stored in
  91          * a local variable before the loop is entered.
  92          * Updated within domain-decomposition.
  93          *
  94          * \note For best performance, store and use a local copy of the ArrayRef.
  95          *
  96          * \returns the local index.
  97          */
  98         ArrayRef<const int> localIndex() const;
  99         /*! \brief The number of atoms from this group index on this rank.
 100          *
 101          * \note For best performance, store and use a local copy of the ArrayRef.
 102          */
 103         std::size_t numAtomsLocal() const;
 104         /*! \brief The number of all atoms from this group index on all ranks together.
 105          *
 106          * \note For best performance, store and use a local copy.
 107          */
 108         std::size_t numAtomsGlobal() const;
 109     private:
 110         /*! \brief Constructs a new atom set by setting a reference to its
 111          * internal data.
 112          * \param[in] data The data for the atom set is stored
 113          * in LocalAtomSetData, which is manged by \ref gmx::LocalAtomSetManager.
 114          */
 115         explicit LocalAtomSet(const internal::LocalAtomSetData &data);
 116
 117         const internal::LocalAtomSetData * data_;
 118
 119 };
 120
 121 } // namespace gmx
 122
 123 #endif