From c2479bc7c75cb9d7fdf80d3c22e9fb6b9c525c8c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ricardo=20Monta=C3=B1ana=20G=C3=B3mez?=
 <rmontanana@gmail.com>
Date: Tue, 24 Jun 2025 12:57:15 +0200
Subject: [PATCH] Fix Regularization error

---
 .gitignore                                |  3 +-
 include/svm_classifier/data_converter.hpp |  1 +
 src/data_converter.cpp                    |  2 +-
 src/multiclass_strategy.cpp               |  6 ++--
 test_param_change.cpp                     | 36 +++++++++++++++++++++++
 5 files changed, 44 insertions(+), 4 deletions(-)
 create mode 100644 test_param_change.cpp

diff --git a/.gitignore b/.gitignore
index 6cb333e..347f8f9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -35,4 +35,5 @@
 build_Release
 build_Debug
 build
-libtorch
\ No newline at end of file
+libtorch
+Testing
diff --git a/include/svm_classifier/data_converter.hpp b/include/svm_classifier/data_converter.hpp
index 3306fdc..9696c73 100644
--- a/include/svm_classifier/data_converter.hpp
+++ b/include/svm_classifier/data_converter.hpp
@@ -138,6 +138,7 @@ namespace svm_classifier {
         std::vector<double> linear_y_space_;
 
         // Single sample storage (for prediction)
+        // Thread-local storage for single sample conversions
         std::vector<svm_node> single_svm_nodes_;
         std::vector<feature_node> single_linear_nodes_;
 
diff --git a/src/data_converter.cpp b/src/data_converter.cpp
index 596354b..7fb7255 100644
--- a/src/data_converter.cpp
+++ b/src/data_converter.cpp
@@ -92,7 +92,7 @@ namespace svm_classifier {
         linear_problem->n = n_features_;
         linear_problem->x = linear_x_space_.data();
         linear_problem->y = linear_y_space_.data();
-        linear_problem->bias = -1; // No bias term by default
+        linear_problem->bias = 1.0; // Add bias term with value 1.0
 
         return linear_problem;
     }
diff --git a/src/multiclass_strategy.cpp b/src/multiclass_strategy.cpp
index baee468..9424062 100644
--- a/src/multiclass_strategy.cpp
+++ b/src/multiclass_strategy.cpp
@@ -321,7 +321,8 @@ namespace svm_classifier {
             linear_params.p = 0.1;
             linear_params.nu = 0.5;
             linear_params.init_sol = nullptr;
-            linear_params.regularize_bias = 0;
+            linear_params.regularize_bias = 1;
+            linear_params.w_recalc = false;
 
             // Check parameters
             const char* error_msg = check_parameter(problem.get(), &linear_params);
@@ -628,7 +629,8 @@ namespace svm_classifier {
             linear_params.p = 0.1;
             linear_params.nu = 0.5;
             linear_params.init_sol = nullptr;
-            linear_params.regularize_bias = 0;
+            linear_params.regularize_bias = 1;
+            linear_params.w_recalc = false;
 
             // Check parameters
             const char* error_msg = check_parameter(problem.get(), &linear_params);
diff --git a/test_param_change.cpp b/test_param_change.cpp
new file mode 100644
index 0000000..8fb7a41
--- /dev/null
+++ b/test_param_change.cpp
@@ -0,0 +1,36 @@
+#include <svm_classifier/svm_classifier.hpp>
+#include <torch/torch.h>
+#include <iostream>
+
+using namespace svm_classifier;
+
+int main() {
+    try {
+        std::cout << "Creating linear SVM..." << std::endl;
+        SVMClassifier svm(KernelType::LINEAR, 1.0);
+        
+        std::cout << "Generating data..." << std::endl;
+        torch::manual_seed(42);
+        auto X = torch::randn({50, 3});
+        auto y = torch::randint(0, 2, {50});
+        
+        std::cout << "Training SVM..." << std::endl;
+        auto metrics = svm.fit(X, y);
+        std::cout << "Training completed successfully!" << std::endl;
+        std::cout << "Is fitted: " << svm.is_fitted() << std::endl;
+        
+        std::cout << "\nChanging to RBF kernel..." << std::endl;
+        nlohmann::json new_params = {{"kernel", "rbf"}};
+        svm.set_parameters(new_params);
+        std::cout << "Parameters changed successfully!" << std::endl;
+        std::cout << "Is fitted after param change: " << svm.is_fitted() << std::endl;
+        
+        std::cout << "\nAll operations completed successfully!" << std::endl;
+        
+    } catch (const std::exception& e) {
+        std::cerr << "Error: " << e.what() << std::endl;
+        return 1;
+    }
+    
+    return 0;
+}
\ No newline at end of file