Method buildTileArray

Src/Base/AMReX_FabArrayBase.cpp:2376–2466

}

void
FabArrayBase::buildTileArray (const IntVect& tileSize, TileArray& ta) const
{
    // Note that we store Tiles always as cell-centered boxes, even if the boxarray is nodal.
    const int N = static_cast<int>(indexArray.size());

    if (tileSize == IntVect::TheZeroVector())
    {
        for (int i = 0; i < N; ++i)
        {
            if (isOwner(i))
            {
                const int K = indexArray[i];
                const Box& bx = boxarray.getCellCenteredBox(K);
                ta.indexMap.push_back(K);
                ta.localIndexMap.push_back(i);
                ta.localTileIndexMap.push_back(0);
                ta.numLocalTiles.push_back(1);
                ta.tileArray.push_back(bx);
            }
        }
    }
    else
    {
        std::vector<int> local_idxs(N);
        std::iota(std::begin(local_idxs), std::end(local_idxs), 0);

#if defined(BL_USE_TEAM)
        const int nworkers = ParallelDescriptor::TeamSize();
        if (nworkers > 1) {
            // reorder it so that each worker will be more likely to work on their own fabs
            std::ranges::stable_sort(local_idxs, [this](int i, int j)
                                     { return  this->distributionMap[this->indexArray[i]]
                                             < this->distributionMap[this->indexArray[j]]; });
        }
#endif

        for (int const i : local_idxs)
        {
            const int K = indexArray[i]; // global index
            const Box& bx = boxarray.getCellCenteredBox(K);

            //
            //  This must be consistent with ParticleContainer::getTileIndex function!!!
            //

            IntVect nt_in_fab, tsize, nleft;
            int ntiles = 1;
            for (int d=0; d<AMREX_SPACEDIM; d++) {
                int ncells = bx.length(d);
                nt_in_fab[d] = std::max(ncells/tileSize[d], 1);
                tsize    [d] = ncells/nt_in_fab[d];
                nleft    [d] = ncells - nt_in_fab[d]*tsize[d];
                ntiles *= nt_in_fab[d];
            }

            IntVect sml, big, ijk;  // note that the initial values are all zero.
            ijk[0] = -1;