Move factory implementation out of header

include/backend.hpp

@@ -1,17 +1,14 @@
 #pragma once
 
-#include <cstddef>
-#include <stdexcept>
+#include <memory>
 
 #include "shape.hpp"
-#ifdef USE_CUDA
-#include "backend/cuda/cuda.cuh"
-#endif
 
 namespace CUDANet {
 
 // Forward declaration
 class Tensor;
+class Backend;
 
 enum BackendType { CUDA_BACKEND, CPU_BACKEND };
 
@@ -21,33 +18,7 @@ struct BackendConfig {
 
 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;
-    }
+    static std::unique_ptr<Backend> create(BackendType backend_type, const BackendConfig& config);
 };
 
 class Backend {

src/backend_factory.cpp

@@ -0,0 +1,40 @@
+#include <stdexcept>
+#include <memory>
+
+#ifdef USE_CUDA
+#include "backend/cuda/cuda.cuh"
+#endif
+
+#include "backend.hpp"
+
+namespace CUDANet {    
+    
+std::unique_ptr<Backend> BackendFactory::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;
+}
+
+} // namespace CUDANet