Method sum_unique

Src/Base/AMReX_MultiFab.cpp:1270–1321

}

Real
MultiFab::sum_unique (int comp,
                      bool local,
                      const Periodicity& period) const
{
    BL_PROFILE("MultiFab::sum_unique()");

    // no duplicately distributed points if cell centered
    if (ixType().cellCentered()) {
        return this->sum(comp, local);
    }

    // Owner is the grid with the lowest grid number containing the data
    std::unique_ptr<iMultiFab> owner_mask = OwnerMask(period);

    Real sm = Real(0.0);
#ifdef AMREX_USE_GPU
    if (Gpu::inLaunchRegion()) {
        auto const& ma = this->const_arrays();
        auto const& msk = owner_mask->const_arrays();
        sm = ParReduce(TypeList<ReduceOpSum>{}, TypeList<Real>{}, *this, IntVect(0),
        [=] AMREX_GPU_DEVICE (int box_no, int i, int j, int k) noexcept
                       -> GpuTuple<Real>
        {
            return msk[box_no](i,j,k) ? ma[box_no](i,j,k,comp) : 0.0_rt;
        });
    } else
#endif
    {
#ifdef AMREX_USE_OMP
#pragma omp parallel if (!system::regtest_reduction) reduction(+:sm)
#endif
        for (MFIter mfi(*this,true); mfi.isValid(); ++mfi)
        {
            Box const& bx = mfi.tilebox();
            Array4<Real const> const& a = this->const_array(mfi);
            Array4<int const> const& msk = owner_mask->const_array(mfi);
            Real tmp = 0.0_rt;
            AMREX_LOOP_3D(bx, i, j, k,
            {
                tmp += msk(i,j,k) ? a(i,j,k,comp) : 0.0_rt;
            });
            sm += tmp; // Do it this way so that it does not break regression tests.
        }
    }

    if (!local) {
        ParallelAllReduce::Sum(sm, ParallelContext::CommunicatorSub());
    }

    return sm;
}

Real
MultiFab::sum_unique (Box const& region, int comp, bool local) const