!1241 replace square and reducesum with squaresumall in lars

Merge pull request !1241 from gziyan/replace_op_in_lars

mindspore/nn/optim/lars.py

@@ -30,9 +30,8 @@ lars_opt = C.MultitypeFuncGraph("lars_opt")
 def _tensor_run_opt(lars, weight_decay, learning_rate, gradient, weight, decay_flag, lars_flag):
     """Apply lars optimizer to the weight parameter."""
     if lars_flag:
-        op_reduce = P.ReduceSum()
-        w_square_sum = op_reduce(F.square(weight))
-        grad_square_sum = op_reduce(F.square(gradient))
+        op_reduce_sum = P.SquareSumAll()
+        w_square_sum, grad_square_sum = op_reduce_sum(weight, gradient)
         if decay_flag:
             grad_t = lars(weight, gradient, w_square_sum, grad_square_sum, weight_decay, learning_rate)
         else: