Option to set error thrown at maximum iterations reached to warning

.github/workflows/gui.yml

@@ -14,12 +14,12 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Set up Node.js
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@v4
         with:
-          node-version: '20'
+          node-version: '22'
 
       - name: Install dependencies
         working-directory: tests/cypress
@@ -43,7 +43,7 @@ jobs:
           FLASK_ENV: development
 
       - name: Run Cypress tests
-        uses: cypress-io/github-action@v5
+        uses: cypress-io/github-action@v6
         with:
           start: npm start
           working-directory: tests/cypress

src/algebra/Integrator.cpp

@@ -4,7 +4,7 @@
 #include "Integrator.h"
 
 Integrator::Integrator(Model* model, double time_step_size, double rho,
-                       double atol, int max_iter) {
+                       double atol, int max_iter, bool max_iter_warning) {
   this->model = model;
   alpha_m = 0.5 * (3.0 - rho) / (1.0 + rho);
   alpha_f = 1.0 / (1.0 + rho);
@@ -19,6 +19,7 @@ Integrator::Integrator(Model* model, double time_step_size, double rho,
   this->time_step_size = time_step_size;
   this->atol = atol;
   this->max_iter = max_iter;
+  this->max_iter_warning = max_iter_warning;
 
   y_af = Eigen::Matrix<double, Eigen::Dynamic, 1>(size);
   ydot_am = Eigen::Matrix<double, Eigen::Dynamic, 1>(size);
@@ -82,9 +83,13 @@ State Integrator::step(const State& old_state, double time) {
 
     // Abort if maximum number of non-linear iterations is reached
     else if (i == max_iter - 1) {
-      throw std::runtime_error(
+      if (max_iter_warning) {
+        std::cout << "Warning: Maximum number of non-linear iterations reached at time " << time << std::endl;
+      } else {
+        throw std::runtime_error(
           "Maximum number of non-linear iterations reached at time " +
           std::to_string(time));
+      }
     }
 
     // Evaluate Jacobian

src/algebra/Integrator.h

@@ -34,6 +34,7 @@ class Integrator {
   double y_coeff_jacobian{0.0};
   double atol{0.0};
   int max_iter{0};
+  bool max_iter_warning{false};
   int size{0};
   int n_iter{0};
   int n_nonlin_iter{0};
@@ -51,9 +52,11 @@ class Integrator {
    * @param rho Spectral radius for generalized-alpha step
    * @param atol Absolut tolerance for non-linear iteration termination
    * @param max_iter Maximum number of non-linear iterations
+   * @param max_iter_warning If true, print a warning instead of throwing error
+   * when maximum iterations is reached
    */
   Integrator(Model* model, double time_step_size, double rho, double atol,
-             int max_iter);
+             int max_iter, bool max_iter_warning = false);
 
   /**
    * @brief Construct a new Integrator object

src/solve/SimulationParameters.cpp

@@ -237,6 +237,8 @@ SimulationParameters load_simulation_params(const nlohmann::json& config) {
   }
   sim_params.sim_abs_tol = sim_config.value("absolute_tolerance", 1e-8);
   sim_params.sim_nliter = sim_config.value("maximum_nonlinear_iterations", 30);
+  sim_params.sim_max_iter_warning =
+      sim_config.value("max_iter_warning", false);
   sim_params.sim_steady_initial = sim_config.value("steady_initial", true);
   sim_params.sim_rho_infty = sim_config.value("rho_infty", 0.5);
   sim_params.output_variable_based =

src/solve/SimulationParameters.h

@@ -67,6 +67,9 @@ struct SimulationParameters {
       false};  ///< Running 0D simulation coupled with external solver
   double sim_external_step_size{0.0};  ///< Step size of external solver if
                                        ///< running coupled
+  bool sim_max_iter_warning{
+      false};  ///< If true, warn instead of throwing when max nonlinear
+               ///< iterations is reached
 };
 
 /// @brief Wrapper class for nlohmann:json with error checking

src/solve/Solver.cpp

@@ -87,7 +87,8 @@ void Solver::setup_integrator() {
   DEBUG_MSG("Setup time integration");
   integrator = Integrator(this->model.get(), simparams.sim_time_step_size,
                           simparams.sim_rho_infty, simparams.sim_abs_tol,
-                          simparams.sim_nliter);
+                          simparams.sim_nliter,
+                          simparams.sim_max_iter_warning);
 
   // Initialize loop
   states = std::vector<State>();

tests/cases/chamber_sphere.json

@@ -26,7 +26,8 @@
     "steady_initial": false,
     "output_variable_based": true,
     "absolute_tolerance": 1e-9,
-    "output_all_cycles": true
+    "output_all_cycles": true,
+    "max_iter_warning": false
   },
   "vessels": [
     {