for new experimental branch

src/polysolve/nonlinear/Solver.cpp

@@ -481,6 +481,12 @@ namespace polysolve::nonlinear
 
             m_current.fDeltaCount = (m_current.fDelta < m_stop.fDelta) ? (m_current.fDeltaCount + 1) : 0;
 
+            if (m_iteration_callback && m_iteration_callback(m_current))
+            {
+                m_status = Status::ObjectiveCustomStop;
+                m_logger.debug("[{}][{}] Iteration callback decided to stop", descent_strategy_name(), m_line_search->name());
+            }
+
             m_logger.debug(
                 "[{}][{}] {} (stopping criteria: {})",
                 descent_strategy_name(), m_line_search->name(), m_current.print_message(), m_stop.print_message());

src/polysolve/nonlinear/Solver.hpp

@@ -79,6 +79,8 @@ namespace polysolve::nonlinear
         void set_line_search(const json &params);
         const json &info() const { return solver_info; }
 
+        void set_iteration_callback(std::function<bool(const Criteria &)> callback) { m_iteration_callback = callback; }
+
         /// @brief If true the solver will not throw an error if the maximum number of iterations is reached
         bool allow_out_of_iterations = false;
 
@@ -87,7 +89,7 @@ namespace polysolve::nonlinear
         const std::shared_ptr<line_search::LineSearch> &line_search() const { return m_line_search; };
 
     protected:
-        /// @brief Compute direction in which the argument should be updated 
+        /// @brief Compute direction in which the argument should be updated
         /// @param objFunc Problem to be minimized
         /// @param x Current input (n x 1)
         /// @param grad Gradient at current step (n x 1)
@@ -139,7 +141,7 @@ namespace polysolve::nonlinear
         // ====================================================================
         //                           Solver state
         // ====================================================================
-        
+
         /// @brief Reset the solver at the start of a minimization
         /// @param ndof number of degrees of freedom
         void reset(const int ndof);
@@ -151,6 +153,8 @@ namespace polysolve::nonlinear
 
         std::vector<int> m_iter_per_strategy;
 
+        std::function<bool(const Criteria &)> m_iteration_callback = nullptr;
+
         // ====================================================================
         //                            Solver info
         // ====================================================================

src/polysolve/nonlinear/line_search/LineSearch.cpp

@@ -111,6 +111,23 @@ namespace polysolve::nonlinear::line_search
         }
 
         const double nan_free_step_size = step_size;
+
+        // TODO: Fix this
+        const bool use_grad_norm = initial_grad.norm() < use_grad_norm_tol;
+        const double starting_step_size = step_size;
+
+        // ----------------------
+        // Find descent step size 1
+        // ----------------------
+        {
+            POLYSOLVE_SCOPED_STOPWATCH("energy min in LS", classical_line_search_time, m_logger);
+            step_size = compute_descent_step_size(x, delta_x, objFunc, use_grad_norm, initial_energy, initial_grad, step_size);
+            if (std::isnan(step_size))
+            {
+                // Superclass::save_sampled_values("failed-line-search-values.csv", x, delta_x, objFunc);
+                return NaN;
+            }
+        }
         // -----------------------------
         // Find collision-free step size
         // -----------------------------
@@ -133,12 +150,10 @@ namespace polysolve::nonlinear::line_search
         if (initial_grad.norm() < 1e-30)
             return step_size;
 
-        // TODO: Fix this
-        const bool use_grad_norm = initial_grad.norm() < use_grad_norm_tol;
-        const double starting_step_size = step_size;
+
 
         // ----------------------
-        // Find descent step size
+        // Find descent step size 2
         // ----------------------
         {
             POLYSOLVE_SCOPED_STOPWATCH("energy min in LS", classical_line_search_time, m_logger);