Implement concat layer

include/layers/concat.cuh

@@ -0,0 +1,45 @@
+#ifndef CUDANET_CONCAT_LAYER_H
+#define CUDANET_CONCAT_LAYER_H
+
+#include <ilayer.cuh>
+
+namespace CUDANet::Layers {
+
+/**
+ * @brief Concatenate layers
+ *
+ */
+class Concat {
+  public:
+    /**
+     * @brief Create a new Concat layer
+     * 
+     * @param layers Layers to concatenate
+     */
+    Concat(const unsigned int inputASize, const unsigned int inputBSize);
+
+    /**
+     * @brief Destroy the Concat layer
+     * 
+     */
+    ~Concat();
+
+    /**
+     * @brief Forward pass of the concat layer
+     *
+     * @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);
+
+  private:
+    unsigned int inputASize;
+    unsigned int inputBSize;
+
+    float* d_output;
+};
+
+}  // namespace CUDANet::Layers
+
+#endif  // CUDANET_CONCAT_LAYER_H