Function GetBndryCells

Src/Base/AMReX_BoxArray.cpp:1841–1896

}

BoxList
GetBndryCells (const BoxArray& ba,
               int             ngrow)
{
    BL_ASSERT(ba.ok());
    BL_ASSERT(!ba.empty());
    //
    // First get list of all ghost cells.
    //
    const IndexType btype = ba.ixType();

    BoxList bcells = ba.boxList();
    bcells.simplify();

    BoxArray tba(bcells);

    BoxList gcells(btype);
    BoxList bl_diff(btype);
    for (int i = 0, N = static_cast<int>(tba.size()); i < N; ++i)
    {
        const Box& bx = tba[i];
        amrex::boxDiff(bl_diff, amrex::grow(bx,ngrow), bx);
        gcells.join(bl_diff);
    }
    //
    // Now strip out intersections with original BoxArray.
    //
    std::vector< std::pair<int,Box> > isects;

    bcells.clear();
    BoxList pieces(btype);
    BoxList bl_tmp(btype);

    for (const Box& gbx : gcells)
    {
        tba.intersections(gbx, isects);
        if (isects.empty())
        {
            bcells.push_back(gbx);
        }
        else
        {
            pieces.clear();
            for (const auto& isec : isects) {
                pieces.push_back(isec.second);
            }
            bl_tmp.complementIn(gbx,pieces);
            bcells.join(bl_tmp);
        }
    }

    gcells = amrex::removeOverlap(bcells);
    gcells.simplify();

    return gcells;
}