the temporary variable uses a value set outside of the PARFOR loop

Question

ha ha 2018-8-13

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/414612-the-temporary-variable-uses-a-value-set-outside-of-the-parfor-loop

编辑： ha ha 2018-8-13

Let' say I have the code like this:

gcp;
a=zeros(1,3);%create the zeros matric 1x3
my_cell={[1 1 1;2 2 2],[3 3 3;4 4 4],[5 5 5;6 6 6;7 7 7]}; %this is the initial cell
parfor I=1:3
    input_data=my_cell{I};%get data coordinate(x,y,z) from my_cell
    [ result ] = my_function( input_data );% The result will be generated from function named "my_function". The result is kx3 matric
    [a,~,~] = union(a,result,'rows');% add the result to the initial matrix a
end

In my code informed this warning: the temporary variable "a" uses a value set outside of the parfor loop. How can I fix this error for "parfor"

Thanks.

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

Walter Roberson 2018-8-13

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/414612-the-temporary-variable-uses-a-value-set-outside-of-the-parfor-loop#answer_332521

在 MATLAB Online 中打开

You cannot do that. You are trying to use|a| as a reduction variable, but union() is not one of the supported reduction operations. You will need to do something like

my_cell={[1 1 1;2 2 2],[3 3 3;4 4 4],[5 5 5;6 6 6;7 7 7]}; %this is the initial cell
N = size(my_cell,2);
a = cell(N,1);
parfor I = 1 : N
  input_data=my_cell{I};%get data coordinate(x,y,z) from my_cell
  [ result ] = my_function( input_data );% The result will be generated from function named "my_function". The result is kx3 matric
  a{I} = result;
end
a = unique(vertcat(a{:}), 'row');