[PL/CT] Provide information whether linear solver needs to compute

ProcessLib/ComponentTransport/ComponentTransportProcess.cpp

@@ -44,15 +44,37 @@ ComponentTransportProcess::ComponentTransportProcess(
     std::unique_ptr<ProcessLib::SurfaceFluxData>&& surfaceflux,
     std::unique_ptr<ChemistryLib::ChemicalSolverInterface>&&
         chemical_solver_interface,
-    bool const is_linear)
+    bool const is_linear,
+    bool const ls_compute_only_upon_timestep_change)
     : Process(std::move(name), mesh, std::move(jacobian_assembler), parameters,
               integration_order, std::move(process_variables),
               std::move(secondary_variables), use_monolithic_scheme),
       _process_data(std::move(process_data)),
       _surfaceflux(std::move(surfaceflux)),
       _chemical_solver_interface(std::move(chemical_solver_interface)),
-      _asm_mat_cache{is_linear, use_monolithic_scheme}
+      _asm_mat_cache{is_linear, use_monolithic_scheme},
+      _ls_compute_only_upon_timestep_change{
+          ls_compute_only_upon_timestep_change}
 {
+    if (ls_compute_only_upon_timestep_change)
+    {
+        if (!is_linear)
+        {
+            OGS_FATAL(
+                "Using the linear solver compute() method only upon timestep "
+                "change only makes sense for linear model equations.");
+        }
+
+        WARN(
+            "You specified that the ComponentTransport linear solver will do "
+            "the compute() step only upon timestep change. This is an expert "
+            "option. It is your responsibility to ensure that "
+            "the conditions for the correct use of this feature are met! "
+            "Otherwise OGS might compute garbage without being recognized. "
+            "There is no "
+            "safety net!");
+    }
+
     _residua.push_back(MeshLib::getOrCreateMeshProperty<double>(
         mesh, "LiquidMassFlowRate", MeshLib::MeshItemType::Node, 1));
 

ProcessLib/ComponentTransport/ComponentTransportProcess.h

@@ -111,7 +111,8 @@ public:
         std::unique_ptr<ProcessLib::SurfaceFluxData>&& surfaceflux,
         std::unique_ptr<ChemistryLib::ChemicalSolverInterface>&&
             chemical_solver_interface,
-        bool const is_linear);
+        bool const is_linear,
+        bool const ls_compute_only_upon_timestep_change);
 
     //! \name ODESystem interface
     //! @{
@@ -141,6 +142,11 @@ public:
                                      const double dt,
                                      int const process_id) override;
 
+    bool shouldLinearSolverComputeOnlyUponTimestepChange() const override
+    {
+        return _ls_compute_only_upon_timestep_change;
+    }
+
 private:
     void initializeConcreteProcess(
         NumLib::LocalToGlobalIndexMap const& dof_table,
@@ -176,6 +182,8 @@ private:
     std::vector<MeshLib::PropertyVector<double>*> _residua;
 
     AssembledMatrixCache _asm_mat_cache;
+
+    bool const _ls_compute_only_upon_timestep_change;
 };
 
 }  // namespace ComponentTransport

ProcessLib/ComponentTransport/CreateComponentTransportProcess.cpp

@@ -256,6 +256,11 @@ std::unique_ptr<Process> createComponentTransportProcess(
         //! \ogs_file_param{prj__processes__process__ComponentTransport__is_linear}
         config.getConfigParameter("is_linear", false);
 
+    auto const ls_compute_only_upon_timestep_change =
+        //! \ogs_file_param{prj__processes__process__ComponentTransport__linear_solver_compute_only_upon_timestep_change}
+        config.getConfigParameter(
+            "linear_solver_compute_only_upon_timestep_change", false);
+
     auto const rotation_matrices = MeshLib::getElementRotationMatrices(
         mesh_space_dimension, mesh.getDimension(), mesh.getElements());
     std::vector<Eigen::VectorXd> projected_specific_body_force_vectors;
@@ -298,7 +303,8 @@ std::unique_ptr<Process> createComponentTransportProcess(
         integration_order, std::move(process_variables),
         std::move(process_data), std::move(secondary_variables),
         use_monolithic_scheme, std::move(surfaceflux),
-        std::move(chemical_solver_interface), is_linear);
+        std::move(chemical_solver_interface), is_linear,
+        ls_compute_only_upon_timestep_change);
 }
 
 }  // namespace ComponentTransport