Using static_cast to make more robust.

paddle/operators/huber_loss_op.h

@@ -32,9 +32,9 @@ struct HuberLossForward {
   HOSTDEVICE T operator()(const T& val) const {
     T abs_val = std::abs(val);
     if (abs_val <= delta) {
-      return 0.5 * val * val;
+      return static_cast<T>(0.5) * val * val;
     } else {
-      return delta * (abs_val - 0.5 * delta);
+      return delta * (abs_val - static_cast<T>(0.5) * delta);
     }
   }