关于人工智能:MindSpore报TypeError-Cannot-joined-the-return-values

1 报错形容
MindSpore 报 TypeError: Cannot joined the return values of different branches, perhaps you need to make them equal.

1.1 零碎环境
*Hardware Environment(Ascend/GPU/CPU): Ascend/GPU/CPU

Software Environment:

– MindSpore version (source or binary): 1.6.0

– Python version (e.g., Python 3.7.5): 3.7.6

– OS platform and distribution (e.g., Linux Ubuntu 16.04): Ubuntu 4.15.0-74-generic

– GCC/Compiler version (if compiled from source):

1.2 根本信息
1.2.1 脚本
在控制流场景中，对同一个变量在不同分支赋不同类型的数据。

import mindspore as ms
import mindspore.nn as nn
from mindspore import ms_function, context

context.set_context(mode=context.GRAPH_MODE)

def test_join():
class JoinNet(nn.Cell):

def construct(self, x):
  out = [1, 2, 3]
  if x > 0:
    out = x
  return out

x = ms.Tensor([1])
net = JoinNet()
res = net(x)
print(“res:”, res)
1.2.2 报错
这里报错信息如下：

TypeError: mindspre/ccsrc/pipeline/jit/static_analysis/static_analysis.cc:780 ProcessEvalResults] Cannot join the return values of different branches, perhaps you need to make them equal.
Type Join Failed: Abstract type AbstractTensor cannot join with AbstractList.
In file ../test.py(11)
if x > 0:
^
起因剖析:

咱们看报错信息，在 TypeError 中，写到 Cannot join the return values of different branches，意思是不反对两个不同分支的 join 操作，out 在 true 分支被赋值为 Tensor 类型，在 false 分支被赋值为 list 类型，条件 x > y 为变量，因而在 return out 语句中无奈确定 out 的数据类型，会导致图模式下的编译出现异常。

2 解决办法
基于下面已知的起因，很容易做出如下批改：

import mindspore as ms
import mindspore.nn as nn
from mindspore import ms_function, context

context.set_context(mode=context.GRAPH_MODE)

def test_join():
class JoinNet(nn.Cell):

def construct(self, x):
  out = Tensor([1, 2, 3])
  if x > 0:
    out = x
  return out

x = ms.Tensor([1])
net = JoinNet()
res = net(x)
print(“res:”, res)
此时执行胜利，输入如下：

res: [1]
3 总结
定位报错问题的步骤：

1、找到报错的用户代码行：if x > 0:
2、剖析控制流的两个分支的 out 数据类型，将其调整成雷同类型。关注变量定义、初始化的正确性。

4 参考文档
https://www.mindspore.cn/docs…