From 7573ce2e4128d5a866ed3a0adb71b5115428359a Mon Sep 17 00:00:00 2001
From: Lisa Julia Nebel <lisa.nebel@dr-blatt.de>
Date: Wed, 28 Aug 2024 15:03:02 +0200
Subject: [PATCH] Add globalToLocal and localToGlobal functions to the
 ParallelWellInfo class

---
 opm/simulators/wells/ParallelWellInfo.cpp | 61 +++++++++++++++++++++++
 opm/simulators/wells/ParallelWellInfo.hpp | 10 ++++
 2 files changed, 71 insertions(+)

diff --git a/opm/simulators/wells/ParallelWellInfo.cpp b/opm/simulators/wells/ParallelWellInfo.cpp
index 97640292e..d77963448 100644
--- a/opm/simulators/wells/ParallelWellInfo.cpp
+++ b/opm/simulators/wells/ParallelWellInfo.cpp
@@ -23,6 +23,7 @@
 #include <opm/input/eclipse/Schedule/Well/Well.hpp>
 #include <opm/input/eclipse/Schedule/Well/WellConnections.hpp>
 
+#include <fmt/format.h>
 #include <cassert>
 #include <iterator>
 #include <numeric>
@@ -119,6 +120,50 @@ GlobalPerfContainerFactory(const IndexSet& local_indices,
     }
 }
 
+template<class Scalar>
+void GlobalPerfContainerFactory<Scalar>::buildLocalToGlobalMap() const {
+    local_to_global_map_.clear();
+    for (const auto& index : local_indices_) {
+        local_to_global_map_[index.local()] = index.global();
+    }
+    l2g_map_built_ = true;
+}
+
+
+template<class Scalar>
+int GlobalPerfContainerFactory<Scalar>::localToGlobal(std::size_t localIndex) const {
+    if (local_indices_.size() == 0)
+        return localIndex;
+    if (!l2g_map_built_)
+        buildLocalToGlobalMap();
+    auto it = local_to_global_map_.find(localIndex);
+    if (it == local_to_global_map_.end())
+        OPM_THROW(std::logic_error, fmt::format("There is no global index for the localIndex {}.", localIndex));
+    return it->second;
+}
+
+template<class Scalar>
+void GlobalPerfContainerFactory<Scalar>::buildGlobalToLocalMap() const {
+    global_to_local_map_.clear();
+    for (const auto& index : local_indices_) {
+        global_to_local_map_[index.global()] = index.local().local();
+    }
+    g2l_map_built_ = true;
+}
+
+template<class Scalar>
+int GlobalPerfContainerFactory<Scalar>::globalToLocal(const int globalIndex) const {
+    if (local_indices_.size() == 0)
+        return globalIndex;
+    if (!g2l_map_built_) {
+        buildGlobalToLocalMap();
+    }
+    auto it = global_to_local_map_.find(globalIndex);
+    if (it == global_to_local_map_.end())
+        return -1; // Global index not found
+    return it->second;
+}
+
 template<class Scalar>
 std::vector<Scalar> GlobalPerfContainerFactory<Scalar>::
 createGlobal(const std::vector<Scalar>& local_perf_container,
@@ -477,6 +522,22 @@ ParallelWellInfo<Scalar>::ParallelWellInfo(const std::pair<std::string, bool>& w
     isOwner_ = (comm_->rank() == 0);
 }
 
+template<class Scalar>
+int ParallelWellInfo<Scalar>::localToGlobal(std::size_t localIndex) const {
+    if(globalPerfCont_)
+        return globalPerfCont_->localToGlobal(localIndex);
+    else // If globalPerfCont_ is not set up, then this is a sequential run and local and global indices are the same.
+        return localIndex;
+}
+
+template<class Scalar>
+int ParallelWellInfo<Scalar>::globalToLocal(const int globalIndex) const {
+    if(globalPerfCont_)
+        return globalPerfCont_->globalToLocal(globalIndex);
+    else // If globalPerfCont_ is not set up, then this is a sequential run and local and global indices are the same.
+        return globalIndex;
+}
+
 template<class Scalar>
 void ParallelWellInfo<Scalar>::communicateFirstPerforation(bool hasFirst)
 {
diff --git a/opm/simulators/wells/ParallelWellInfo.hpp b/opm/simulators/wells/ParallelWellInfo.hpp
index 4439ff9bb..3eeac1b9e 100644
--- a/opm/simulators/wells/ParallelWellInfo.hpp
+++ b/opm/simulators/wells/ParallelWellInfo.hpp
@@ -161,8 +161,16 @@ public:
                            std::size_t num_components) const;
 
     int numGlobalPerfs() const;
+    int globalToLocal(const int globalIndex) const;
+    int localToGlobal(std::size_t localIndex) const;
 
 private:
+    void buildLocalToGlobalMap() const;
+    void buildGlobalToLocalMap() const;
+    mutable std::unordered_map<std::size_t, int> local_to_global_map_; // Cache for L2G mapping
+    mutable std::unordered_map<int, std::size_t> global_to_local_map_; // Cache for G2L mapping
+    mutable bool l2g_map_built_ = false;
+    mutable bool g2l_map_built_ = false;
     const IndexSet& local_indices_;
     Parallel::Communication comm_;
     int num_global_perfs_;
@@ -208,6 +216,8 @@ public:
     /// \brief Collectively decide which rank has first perforation.
     void communicateFirstPerforation(bool hasFirst);
 
+    int globalToLocal(const int globalIndex) const;
+    int localToGlobal(std::size_t localIndex) const;
 
     /// If the well does not have any open connections the member rankWithFirstPerf
     /// is not initialized, and no broadcast is performed. In this case the argument