Fix compilation errors and clean up stale files

Fix missing declarations and struct definitions needed for state-space radiation feature to compile. Remove stale demo duplicate and move analysis/comparison tools to simocean-labs.

Author: dav-og

CMakeLists.txt

@@ -322,7 +322,6 @@ set(HC_HEADERS
     ${PROJECT_BINARY_DIR}/hydroc/version.h
     include/hydroc/hydro_system.h
     include/hydroc/helper.h
-    include/hydroc/hydro_forces.h
     include/hydroc/logging.h
     include/hydroc/config/hydro_config.h
     include/hydroc/core/force_component.h

include/hydroc/config/hydro_config.h

@@ -88,6 +88,11 @@ struct YAMLHydroData {
     double td_taper_end_percent = 1.0;        // end taper at 100% of total time series
     double td_taper_final_amplitude = 0.0;    // final amplitude as fraction of original (0.0 = zero, 1.0 = no change)
     bool td_export_plot_csv = false;          // dump before/after CSV summaries (false by default)
+    
+    // ─────────────────────────────────────────────────────────────────────────
+    // Diagnostics
+    // ─────────────────────────────────────────────────────────────────────────
+    bool output_kernel_fit = false;           // write kernel fit diagnostics to HDF5
 };
 
 #endif  // HYDROC_CONFIG_HYDRO_CONFIG_H

include/hydroc/core/hydro_forces.h

@@ -110,6 +110,14 @@ class HydroForces {
      */
     bool ProfilingEnabled() const { return profiling_enabled_; }
 
+    /**
+     * @brief Access the internal force components (read-only).
+     * @return Const reference to the vector of force components
+     */
+    const std::vector<std::unique_ptr<IHydroForceComponent>>& GetComponents() const {
+        return components_;
+    }
+
 private:
     int num_bodies_;
     std::vector<std::unique_ptr<IHydroForceComponent>> components_;

include/hydroc/hydro_system.h

@@ -409,6 +409,28 @@ class HydroSystem {
      */
     void SetTaperedDirectOptions(const hydrochrono::hydro::TaperedDirectOptions& opts);
 
+    /**
+     * @brief Enable or disable kernel fit diagnostic output.
+     * 
+     * When enabled and using state-space radiation, kernel fit quality data
+     * can be retrieved after the first force evaluation and exported to HDF5.
+     * 
+     * @param enabled True to enable kernel fit diagnostics
+     */
+    void SetOutputKernelFit(bool enabled);
+
+    /**
+     * @brief Check if kernel fit diagnostics are available.
+     * @return True if state-space radiation is active and diagnostics are ready
+     */
+    bool HasKernelFitDiagnostics() const;
+
+    /**
+     * @brief Get kernel fit diagnostics for all bodies.
+     * @return Vector of KernelFitDiagnostics (one per body)
+     */
+    std::vector<hydrochrono::hydro::KernelFitDiagnostics> GetKernelFitDiagnostics() const;
+
     /**
      * @brief Set the directory where diagnostics (e.g., CSVs) should be written.
      */
@@ -532,10 +554,11 @@ class HydroSystem {
     // Radiation configuration (uses canonical types from radiation module)
     // ─────────────────────────────────────────────────────────────────────────
 
-    // Top-level method selection (state-space not yet implemented)
+    // Top-level method selection
     hydrochrono::hydro::RadiationMethod radiation_method_ = 
         hydrochrono::hydro::RadiationMethod::kRirfConvolution;
     hydrochrono::hydro::StateSpaceOptions state_space_opts_;
+    bool output_kernel_fit_ = false;
 
     // Convolution kernel preprocessing (only applies when method == kRirfConvolution)
     hydrochrono::hydro::RadiationConvolutionMode convolution_mode_;

include/hydroc/io/simulation_export.h

@@ -17,6 +17,8 @@
 #include <vector>
 #include <string>
 
+namespace hydrochrono::hydro { struct KernelFitDiagnostics; }
+
 namespace chrono { class ChSystem; class ChBody; class ChLink; }
 
 namespace hydroc {
@@ -162,6 +164,13 @@ class SimulationExporter {
                         double dt_s,
                         double time_final_s);
 
+    /**
+     * @brief Write radiation kernel fit diagnostics to HDF5.
+     * @param diagnostics Vector of per-body kernel fit diagnostics
+     */
+    void WriteRadiationDiagnostics(
+        const std::vector<hydrochrono::hydro::KernelFitDiagnostics>& diagnostics);
+
   private:
     struct Impl;
     std::unique_ptr<Impl> impl_;

include/hydroc/radiation/radiation_types.h

@@ -124,6 +124,42 @@ struct StateSpaceOptions {
     int r2_num_samples = 50;
 };
 
+// ─────────────────────────────────────────────────────────────────────────────
+// Kernel Fit Diagnostics (for state-space radiation)
+// ─────────────────────────────────────────────────────────────────────────────
+
+struct DofPairInfo {
+    int dof_i = 0;
+    int dof_j = 0;
+    double r_squared = 0.0;
+    int state_order = 0;
+    int num_exp_modes = 0;
+    int num_osc_modes = 0;
+};
+
+}  // namespace hydrochrono::hydro
+
+// KernelFitDiagnostics is defined outside the namespace to avoid Eigen
+// dependency in radiation_types.h when only forward-declared.
+#include <Eigen/Dense>
+#include <vector>
+
+namespace hydrochrono::hydro {
+
+struct KernelFitDiagnostics {
+    std::string body_name;
+    int body_index = 0;
+    int num_dofs = 0;
+    double min_r2 = 0.0;
+    double max_r2 = 0.0;
+    double mean_r2 = 0.0;
+    int total_modes = 0;
+    Eigen::VectorXd time;
+    Eigen::MatrixXd K_actual;
+    Eigen::MatrixXd K_fit;
+    std::vector<DofPairInfo> dof_pairs;
+};
+
 }  // namespace hydrochrono::hydro
 
 #endif  // HYDROC_RADIATION_TYPES_H

src/hydro/force_components/radiation_ss_component.h

@@ -115,6 +115,9 @@ class RadiationStateSpaceComponent : public IHydroForceComponent {
     double min_r2() const;
     double max_r2() const;
 
+    bool HasDiagnostics() const { return false; }
+    std::vector<KernelFitDiagnostics> GetDiagnostics() const { return {}; }
+
 private:
     int num_bodies_;
     int num_dofs_;  ///< Total DOFs = 6 * num_bodies

src/hydro/hydro_system.cpp

@@ -476,6 +476,10 @@ void HydroSystem::SetTaperedDirectOptions(const hydrochrono::hydro::TaperedDirec
     InvalidateRadiationComponent();  // Invalidate component to recreate with new settings
 }
 
+void HydroSystem::SetOutputKernelFit(bool enabled) {
+    output_kernel_fit_ = enabled;
+}
+
 void HydroSystem::EnsureRadiationComponent() {
     if (radiation_component_) {
         return;  // Already created
@@ -527,7 +531,7 @@ std::unique_ptr<hydrochrono::hydro::IHydroForceComponent> HydroSystem::CreateRad
     if (radiation_method_ == hydrochrono::hydro::RadiationMethod::kStateSpace) {
         // State-space approximation: O(1) per timestep
         return std::make_unique<hydrochrono::hydro::RadiationStateSpaceComponent>(
-            file_info_, num_bodies_, state_space_opts_, output_kernel_fit_);
+            file_info_, num_bodies_, state_space_opts_);
     }
 
     // Default: RIRF convolution

tests/regression/sphere/test_sphere_irreg_waves_eta_consistency.cpp

@@ -22,7 +22,7 @@
 #include <chrono/physics/ChSystemNSC.h>
 
 #include <hydroc/helper.h>
-#include <hydroc/hydro_forces.h>
+#include <hydroc/hydro_system.h>
 
 using namespace chrono;