diff --git a/CMakeLists.txt b/CMakeLists.txt
index 028d451..4ae412d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,7 +11,6 @@ if(CUDAToolkit_FOUND)
     option(USE_CUDA "Use CUDA implementation" ON)
 else()
     option(USE_CUDA "Use CUDA implementation" OFF)
-    message(STATUS "CUDA not found. Defaulting to CPU implementation.")
 endif()
 
 if(USE_CUDA)
@@ -19,7 +18,7 @@ if(USE_CUDA)
     add_definitions(-DUSE_CUDA)
     message(STATUS "Building library with CUDA support")
 else()
-    message(STATUS "Building library without CUDA support")
+    message(STATUS "CUDA not found or disabled. Defaulting to CPU implementation.")
 endif()
 
 
diff --git a/include/layers/activation.cuh b/include/layers/activation.hpp
similarity index 87%
rename from include/layers/activation.cuh
rename to include/layers/activation.hpp
index 0496f7b..5c8f28b 100644
--- a/include/layers/activation.cuh
+++ b/include/layers/activation.hpp
@@ -47,11 +47,21 @@ class Activation {
   private:
     ActivationType activationType;
     int length;
+
+#ifdef USE_CUDA
     int gridSize;
 
     float* d_softmax_sum;
     float* d_max;
 
+    void activateCUDA(float* d_input);
+
+    void initCUDA();
+    void delCUDA();
+#else
+    void activateCPU(float* input);
+#endif
+
 };
 
 
diff --git a/src/layers/activation.cu b/src/backends/cuda/layers/activation.cu
similarity index 89%
rename from src/layers/activation.cu
rename to src/backends/cuda/layers/activation.cu
index 6d14e78..9b9dbca 100644
--- a/src/layers/activation.cu
+++ b/src/backends/cuda/layers/activation.cu
@@ -1,7 +1,6 @@
-#include <iostream>
 #include <vector>
 
-#include "activation.cuh"
+#include "activation.hpp"
 #include "activation_functions.cuh"
 #include "cuda_helper.cuh"
 #include "matmul.cuh"
@@ -9,8 +8,7 @@
 
 using namespace CUDANet::Layers;
 
-Activation::Activation(ActivationType activation, const int length)
-    : activationType(activation), length(length) {
+void Activation::initCUDA() {
     if (activationType == SOFTMAX) {
         d_softmax_sum = nullptr;
         CUDA_CHECK(cudaMalloc((void**)&d_softmax_sum, sizeof(float) * length));
@@ -22,14 +20,14 @@ Activation::Activation(ActivationType activation, const int length)
     gridSize = (length + BLOCK_SIZE - 1) / BLOCK_SIZE;
 }
 
-Activation::~Activation() {
+void Activation::delCUDA() {
     if (activationType == SOFTMAX) {
         CUDA_CHECK(cudaFree(d_softmax_sum));
         CUDA_CHECK(cudaFree(d_max));
     }
 }
 
-void Activation::activate(float* d_input) {
+void Activation::activateCUDA(float* d_input) {
 
     // float sum = 0.0f;
 
diff --git a/src/layers/activation.cpp b/src/layers/activation.cpp
new file mode 100644
index 0000000..08a864d
--- /dev/null
+++ b/src/layers/activation.cpp
@@ -0,0 +1,31 @@
+#include <stdexcept>
+#include <vector>
+
+#include "activation.hpp"
+
+using namespace CUDANet::Layers;
+
+Activation::Activation(ActivationType activation, const int length)
+    : activationType(activation), length(length) {
+#ifdef USE_CUDA
+    initCUDA();
+#endif
+}
+
+Activation::~Activation() {
+#ifdef USE_CUDA
+    delCUDA();
+#endif
+}
+
+void Activation::activateCPU(float* input) {
+    throw std::logic_error("Not implemented");
+}
+
+void Activation::activate(float* input) {
+#ifdef USE_CUDA
+    activateCUDA(input);
+#else
+    activateCPU(input);
+#endif
+}
\ No newline at end of file