Migrate concat layer

include/layers/concat.hpp

@@ -0,0 +1,57 @@
+#ifndef CUDANET_CONCAT_LAYER_H
+#define CUDANET_CONCAT_LAYER_H
+
+#include "layer.hpp"
+
+namespace CUDANet::Layers {
+
+/**
+ * @brief Concatenate layers
+ *
+ */
+class Concat {
+  public:
+    /**
+     * @brief Create a new Concat layer
+     *
+     * @param inputASize Size of the first input
+     * @param inputBSize Size of the second input
+     */
+    Concat(const int inputASize, const int inputBSize);
+
+    /**
+     * @brief Destroy the Concat layer
+     *
+     */
+    ~Concat();
+
+    /**
+     * @brief Concatenates the two inputs
+     *
+     * @param d_input_A Device pointer to the first input
+     * @param d_input_B Device pointer to the second input
+     *
+     * @return Device pointer to the output
+     */
+    float* forward(const float* d_input_A, const float* d_input_B);
+
+    int getOutputSize();
+
+  private:
+    int inputASize;
+    int inputBSize;
+
+    float* forwardCPU(const float* input_A, const float* input_B);
+
+#ifdef USE_CUDA
+    float* d_output;
+    float* forwardCUDA(const float* d_input_A, const float* d_input_B);
+
+    void initCUDA();
+    void delCUDA();
+#endif
+};
+
+}  // namespace CUDANet::Layers
+
+#endif  // CUDANET_CONCAT_LAYER_H