Implement backend factory

include/backend.hpp

@@ -1,14 +1,55 @@
 #pragma once
 
 #include <cstddef>
+#include <stdexcept>
 
 #include "shape.hpp"
+#ifdef USE_CUDA
+#include "backend/cuda/cuda.cuh"
+#endif
 
 namespace CUDANet {
 
 // Forward declaration
 class Tensor;
 
+enum BackendType { CUDA_BACKEND, CPU_BACKEND };
+
+struct BackendConfig {
+    int device_id = 0;
+};
+
+class BackendFactory {
+  public:
+    static std::unique_ptr<Backend> create(BackendType backend_type, const BackendConfig& config) {
+        switch (backend_type)
+        {
+        case BackendType::CUDA_BACKEND:
+            #ifdef USE_CUDA
+
+            if (!CUDANet::Backends::CUDA::is_cuda_available()) {
+                throw std::runtime_error("No CUDA devices found")
+            }
+
+            auto cuda = std::make_unique<CUDANet::Backends::CUDA>(config);
+            cuda.initialize();
+
+            return cuda;
+
+            #else
+            throw std::runtime_error("Library was compiled without CUDA support.");
+            #endif
+
+            break;
+        
+        default:
+            break;
+        }
+
+        return nullptr;
+    }
+};
+
 class Backend {
   public:
     // Memory management

include/backend/cuda/cuda.cuh

@@ -27,7 +27,14 @@ do { \
 namespace CUDANet::Backends {
 
 class CUDA : public Backend {
+  private:
+    int device_id;
   public:
+    CUDA(const BackendConfig& config);
+
+    static bool is_cuda_available();
+    void initialize();
+
     // Memory management
     void* allocate(size_t bytes) override;
     void  deallocate(void* ptr) override;

include/cudanet.hpp

@@ -41,15 +41,15 @@
 #include "layers/concat.hpp"
 
 // ============================================================================
-// Utilities
+// Dataset Labels
 // ============================================================================
 
-#include "utils/imagenet.hpp"
+#include "datasets/imagenet.hpp"
 
 // ============================================================================
 // Backend-Specific Includes (conditionally compiled)
 // ============================================================================
 
 #ifdef USE_CUDA
-#include "backend/cuda/cuda_backend.cuh"
+#include "backend/cuda/all.cuh"
 #endif

include/shape.hpp

@@ -9,6 +9,7 @@
 #endif
 
 #include <format>
+#include <stdexcept>
 #include <vector>
 
 namespace CUDANet {