From 4c59df55941ae5c6aa004fa569725e508a78e621 Mon Sep 17 00:00:00 2001
From: Lisa Julia Nebel <lisa.nebel@dr-blatt.de>
Date: Tue, 12 Nov 2024 15:16:11 +0100
Subject: [PATCH] Add function sumDistributed to MultisegmentWellEquations

This functions sums all contributions of a multisegment well for the diagonal of D and the residual.
---
 opm/simulators/wells/MultisegmentWellEquations.cpp | 11 +++++++++++
 opm/simulators/wells/MultisegmentWellEquations.hpp |  4 ++++
 2 files changed, 15 insertions(+)

diff --git a/opm/simulators/wells/MultisegmentWellEquations.cpp b/opm/simulators/wells/MultisegmentWellEquations.cpp
index a8ca05a43..d229c7191 100644
--- a/opm/simulators/wells/MultisegmentWellEquations.cpp
+++ b/opm/simulators/wells/MultisegmentWellEquations.cpp
@@ -37,6 +37,7 @@
 #include <opm/simulators/linalg/matrixblock.hh>
 #include <opm/simulators/linalg/SmallDenseMatrixUtils.hpp>
 
+#include <opm/simulators/wells/WellHelpers.hpp>
 #include <opm/simulators/wells/MSWellHelpers.hpp>
 #include <opm/simulators/wells/MultisegmentWellGeneric.hpp>
 #include <opm/simulators/wells/WellInterfaceGeneric.hpp>
@@ -409,6 +410,16 @@ extractCPRPressureMatrix(PressureMatrix& jacobian,
     }
 }
 
+template<class Scalar, int numWellEq, int numEq>
+void MultisegmentWellEquations<Scalar,numWellEq,numEq>::
+sumDistributed(Parallel::Communication comm)
+{
+    // accumulate resWell_ and duneD_ in parallel to get effects of all perforations (might be distributed)
+    // we need to do this for all segments in the residual and on the diagonal of D 
+    for (int seg = 0; seg < well_.numberOfSegments(); ++seg)
+        Opm::wellhelpers::sumDistributedWellEntries(duneD_[seg][seg], resWell_[seg], comm);
+}
+
 #define INSTANTIATE(T, numWellEq, numEq)                                                       \
     template class MultisegmentWellEquations<T,numWellEq,numEq>;                               \
     template void MultisegmentWellEquations<T,numWellEq,numEq>::                               \
diff --git a/opm/simulators/wells/MultisegmentWellEquations.hpp b/opm/simulators/wells/MultisegmentWellEquations.hpp
index fbc50469d..ebbe69942 100644
--- a/opm/simulators/wells/MultisegmentWellEquations.hpp
+++ b/opm/simulators/wells/MultisegmentWellEquations.hpp
@@ -22,6 +22,7 @@
 #ifndef OPM_MULTISEGMENTWELL_EQUATIONS_HEADER_INCLUDED
 #define OPM_MULTISEGMENTWELL_EQUATIONS_HEADER_INCLUDED
 
+#include <opm/simulators/utils/ParallelCommunication.hpp>
 #include <opm/simulators/wells/ParallelWellInfo.hpp>
 #include <dune/common/fmatrix.hh>
 #include <dune/common/fvector.hh>
@@ -121,6 +122,9 @@ public:
                                   const int seg_pressure_var_ind,
                                   const WellState<Scalar>& well_state) const;
 
+    //! \brief Sum with off-process contribution.
+    void sumDistributed(Parallel::Communication comm);
+
     //! \brief Returns a const reference to the residual.
     const BVectorWell& residual() const
     {