Allow rerouting in standard network

opm/input/eclipse/Schedule/Network/ExtNetwork.hpp

@@ -38,6 +38,7 @@ public:
     ExtNetwork() = default;
     bool active() const;
     void add_branch(Branch branch);
+    void add_or_replace_branch(Branch branch);
     void drop_branch(const std::string& uptree_node, const std::string& downtree_node);
     bool has_node(const std::string& name) const;
     void update_node(Node node);

src/opm/input/eclipse/Schedule/KeywordHandlers.cpp

@@ -873,9 +873,9 @@ File {} line {}.)", wname, location.keyword, location.filename, location.lineno)
                                 const auto alq_eq = Network::Branch::AlqEqfromString(record.getItem<ParserKeywords::GRUPNET::ALQ_SURFACE_DENSITY>().get<std::string>(0));
                                 if (alq_eq == Network::Branch::AlqEQ::ALQ_INPUT) {
                                     const double alq_value = record.getItem<ParserKeywords::GRUPNET::ALQ>().get<double>(0);
-                                    network.add_branch(Network::Branch(downtree_node, uptree_node, vfp_table, alq_value));
+                                    network.add_or_replace_branch(Network::Branch(downtree_node, uptree_node, vfp_table, alq_value));
                                 } else {
-                                     network.add_branch(Network::Branch(downtree_node, uptree_node, vfp_table, alq_eq));
+                                     network.add_or_replace_branch(Network::Branch(downtree_node, uptree_node, vfp_table, alq_eq));
                                 }
                             }
                             nodes.push_back(node);

src/opm/input/eclipse/Schedule/Network/ExtNetwork.cpp

@@ -86,6 +86,42 @@ void ExtNetwork::add_branch(Branch branch)
     this->m_branches.push_back( std::move(branch) );
 }
 
+void ExtNetwork::add_or_replace_branch(Branch branch)
+{
+    const std::string& uptree_node = branch.uptree_node();
+    const std::string& downtree_node = branch.downtree_node();
+
+    // Add any missing nodes
+    for (const std::string& nodename : { downtree_node, uptree_node }) {
+        if (!this->has_node(nodename)) {
+            this->m_nodes.insert_or_assign(nodename, Node{nodename});
+        }
+        if (!this->has_indexed_node_name(nodename)) {
+            this->add_indexed_node_name(nodename);
+        }
+    }
+    
+    // Remote any other branch uptree from downtree_node
+    auto uptree_link = this->uptree_branch( downtree_node );
+    if (uptree_link.has_value()){
+        const auto& old_uptree_node = uptree_link.value().uptree_node();
+        this->drop_branch(old_uptree_node, downtree_node);
+    }
+    
+    // Update existing branch
+    auto downtree_branches = this->downtree_branches( uptree_node );
+    if (!downtree_branches.empty()) {
+        auto branch_iter = std::find_if(this->m_branches.begin(), this->m_branches.end(), [&uptree_node, &downtree_node](const Branch& b) { return (b.uptree_node() == uptree_node && b.downtree_node() == downtree_node); });
+        if (branch_iter != this->m_branches.end()) {
+            *branch_iter = branch;
+            return;
+        }
+    }
+    
+    this->m_branches.push_back( std::move(branch) );
+}
+
+
 void ExtNetwork::drop_branch(const std::string& uptree_node, const std::string& downtree_node) {
     auto downtree_branches = this->downtree_branches( downtree_node );
     if (downtree_branches.empty()) {