diff --git a/include/Layer.h b/include/Layer.h
index 9ec37d4..7059695 100644
--- a/include/Layer.h
+++ b/include/Layer.h
@@ -43,7 +43,7 @@ public:
     Layer(Network *net, dataDim_t input_dim);
     virtual ~Layer();
 
-    value_type* infer(dataDim_t &dim, value_type* srcData) {
+    virtual value_type* infer(dataDim_t &dim, value_type* srcData) {
         std::cout<<"No infer action for this layer\n";
         return NULL;
     }
@@ -86,7 +86,7 @@ public:
           const char* fname_weights, const char* fname_bias); 
     virtual ~Dense();
 
-    value_type* infer(dataDim_t &dim, value_type* srcData);
+    virtual value_type* infer(dataDim_t &dim, value_type* srcData);
 
 protected:
     value_type *dstData;  //where results will be putted
@@ -111,7 +111,7 @@ public:
     Activation(Network *net, dataDim_t input_dim, tkdnnActivationMode_t act_mode); 
     virtual ~Activation();
 
-    value_type* infer(dataDim_t &dim, value_type* srcData);
+    virtual value_type* infer(dataDim_t &dim, value_type* srcData);
 
 protected:
     tkdnnActivationMode_t act_mode;
@@ -130,7 +130,7 @@ public:
             const char* fname_weights, const char* fname_bias); 
     virtual ~Conv2d();
 
-    value_type* infer(dataDim_t &dim, value_type* srcData);
+    virtual value_type* infer(dataDim_t &dim, value_type* srcData);
 
 protected:
     value_type *dstData;  //where results will be putted
@@ -157,7 +157,7 @@ public:
             const char* fname_weights, const char* fname_bias); 
     virtual ~Conv3d();
 
-    value_type* infer(dataDim_t &dim, value_type* srcData);
+    virtual value_type* infer(dataDim_t &dim, value_type* srcData);
 
 protected:
     value_type *dstData;  //where results will be putted
@@ -185,7 +185,7 @@ public:
     Flatten(Network *net, dataDim_t input_dim); 
     virtual ~Flatten();
 
-    value_type* infer(dataDim_t &dim, value_type* srcData);
+    virtual value_type* infer(dataDim_t &dim, value_type* srcData);
 
 protected:
     value_type *dstData;  //where results will be putted
@@ -202,7 +202,7 @@ public:
     MulAdd(Network *net, dataDim_t input_dim, value_type mul, value_type add); 
     virtual ~MulAdd();
 
-    value_type* infer(dataDim_t &dim, value_type* srcData);
+    virtual value_type* infer(dataDim_t &dim, value_type* srcData);
 
 protected:
     value_type mul, add;
@@ -231,7 +231,7 @@ public:
             int strideH, int strideW, tkdnnPoolingMode_t pool_mode); 
     virtual ~Pooling();
 
-    value_type* infer(dataDim_t &dim, value_type* srcData);
+    virtual value_type* infer(dataDim_t &dim, value_type* srcData);
 
 protected: