add infer code

recommend-model-produce/src/main/python/models/dssm/static_model.py

@@ -106,7 +106,8 @@ class StaticModel():
             import paddle.distributed.fleet as fleet
             optimizer = fleet.distributed_optimizer(optimizer, strategy)
         if is_infer:
-            optimizer.minimize(paddle.mean(0))
+            zero_var = paddle.zeros(shape=[1], dtype='float32')
+            optimizer.minimize(paddle.mean(zero_var))
         else:
             optimizer.minimize(self._cost)