fix tensor usage in sgd-op

paddle/operators/sgd_op.h

@@ -14,6 +14,7 @@ limitations under the License. */
 
 #pragma once
 #include "glog/logging.h"
+#include "paddle/framework/eigen.h"
 #include "paddle/framework/operator.h"
 
 namespace paddle {
@@ -30,8 +31,10 @@ public:
 
     param_out->mutable_data<T>(ctx.GetPlace());
 
-    param_out->flat<T>().device(*(ctx.GetEigenDevice<Place>())) =
-        param.flat<T>() - lr * grad.flat<T>();
+    framework::EigenVector<T>::Flatten(*param_out)
+        .device(*(ctx.GetEigenDevice<Place>())) =
+        framework::EigenVector<T>::Flatten(param) -
+        lr * framework::EigenVector<T>::Flatten(grad);
   }
 };