Merge pull request #690 from zhangyang0701/develop

add const attribute. close #689

src/framework/tensor.h

@@ -257,12 +257,10 @@ class Tensor {
   struct FPGAArgs {
     float scale;
 
-    inline float *scale_pointer() { return &scale; }
+    inline float *scale_pointer() const { return &scale; }
   };
 
-  struct FPGAArgs &fpga_args() {
-    return fpgaArgs_;
-  }
+  const struct FPGAArgs &fpga_args() const { return fpgaArgs_; }
 #endif
 
  private: