From 802e73fe2864d716b4a918ac1d2e8b176887c1ca Mon Sep 17 00:00:00 2001
From: Vegard Kippe <vkip@equinor.com>
Date: Fri, 20 Dec 2024 10:46:14 +0100
Subject: [PATCH] Fix RFT output for shut distributed wells and permamently
 inactive wells split across processors (partition method 3 issue only).

---
 .../flow/GenericOutputBlackoilModule.cpp      | 28 +++++++++----------
 .../flow/GenericOutputBlackoilModule.hpp      |  2 +-
 2 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/opm/simulators/flow/GenericOutputBlackoilModule.cpp b/opm/simulators/flow/GenericOutputBlackoilModule.cpp
index 0a345e8ae..7647f8893 100644
--- a/opm/simulators/flow/GenericOutputBlackoilModule.cpp
+++ b/opm/simulators/flow/GenericOutputBlackoilModule.cpp
@@ -407,32 +407,30 @@ template<class FluidSystem>
 void GenericOutputBlackoilModule<FluidSystem>::
 accumulateRftDataParallel(const Parallel::Communication& comm) {
     if (comm.size() > 1) {
-        collectRftMapOnRoot(oilConnectionPressures_, comm);
-        collectRftMapOnRoot(waterConnectionSaturations_, comm);
-        collectRftMapOnRoot(gasConnectionSaturations_, comm);
+        gatherAndUpdateRftMap(oilConnectionPressures_, comm);
+        gatherAndUpdateRftMap(waterConnectionSaturations_, comm);
+        gatherAndUpdateRftMap(gasConnectionSaturations_, comm);
     }
 }
 
 template<class FluidSystem>
 void GenericOutputBlackoilModule<FluidSystem>::
-collectRftMapOnRoot(std::map<std::size_t, Scalar>& local_map, const Parallel::Communication& comm) {
+gatherAndUpdateRftMap(std::map<std::size_t, Scalar>& local_map, const Parallel::Communication& comm) {
 
     std::vector<std::pair<int, Scalar>> pairs(local_map.begin(), local_map.end());
     std::vector<std::pair<int, Scalar>> all_pairs;
     std::vector<int> offsets;
 
-    std::tie(all_pairs, offsets) = Opm::gatherv(pairs, comm, 0);
+    std::tie(all_pairs, offsets) = Opm::allGatherv(pairs, comm);
 
-    // Insert/update map values on root
-    if (comm.rank() == 0) {
-        for (auto i=static_cast<std::size_t>(offsets[1]); i<all_pairs.size(); ++i) {
-            const auto& key_value = all_pairs[i];
-            if (auto candidate = local_map.find(key_value.first); candidate != local_map.end()) {
-                const Scalar prev_value = candidate->second;
-                candidate->second = std::max(prev_value, key_value.second);
-            } else {
-                local_map[key_value.first] = key_value.second;
-            }
+    // Update maps on all ranks
+    for (auto i=static_cast<std::size_t>(offsets[0]); i<all_pairs.size(); ++i) {
+        const auto& key_value = all_pairs[i];
+        if (auto candidate = local_map.find(key_value.first); candidate != local_map.end()) {
+            const Scalar prev_value = candidate->second;
+            candidate->second = std::max(prev_value, key_value.second);
+        } else {
+            local_map[key_value.first] = key_value.second;
         }
     }
 }
diff --git a/opm/simulators/flow/GenericOutputBlackoilModule.hpp b/opm/simulators/flow/GenericOutputBlackoilModule.hpp
index b8f3afdcc..79fe86cd4 100644
--- a/opm/simulators/flow/GenericOutputBlackoilModule.hpp
+++ b/opm/simulators/flow/GenericOutputBlackoilModule.hpp
@@ -387,7 +387,7 @@ protected:
 
     virtual bool isDefunctParallelWell(std::string wname) const = 0;
 
-    void collectRftMapOnRoot(std::map<std::size_t, Scalar>& local_map, const Parallel::Communication& comm);
+    void gatherAndUpdateRftMap(std::map<std::size_t, Scalar>& local_map, const Parallel::Communication& comm);
 
     const EclipseState& eclState_;
     const Schedule& schedule_;