parfor code can not run after wrapping into a function

Question

Yulin 2022-11-23

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1860713-parfor-code-can-not-run-after-wrapping-into-a-function

回答： Raymond Norris 2022-11-24

I have a very simple code snippet with parfor that runs alright：

c = cell(1, 10);

parfor ii = 1:10

c{ii} = 1;

end

but after wrapping it into a function by adding just one code line 'function tempFcn()', Matlab reports a syntax error: the output variable 'c' should not be used after the PARFOR loop(I'm using the chinese version, so may not be the exact words in english)：

function tempFcn()

c = cell(1, 10);

parfor ii = 1:10

c{ii} = 1;

end

why is this? As I have to use a similar code snipnet in a function, how to solve this problem？

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Raymond Norris 2022-11-24

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1860713-parfor-code-can-not-run-after-wrapping-into-a-function#answer_1110718

在 MATLAB Online 中打开

Hi @Yulin, when you write your code without the function prototype

function tempFcn()

then as a script, MATLAB doesn't know if the variable c will be used in other functions/scripts or used at your command line. When you convert your script to a function, then MATLAB knows that, in your simple example, the variable c is not being used. In this case, the Code Analyzer will provide the following warning

The output variable 'c' might not be used after the PARFOR loop.

But keep in mind, this is just a warning -- this has no bearing on your code and ought to work fine.