How to 'load' data inside a parfor loop in an effective way?

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Merse Gaspar
Merse Gaspar 2019-9-25
评论： Edric Ellis 2019-9-26
Let suppose the following general code structure.
parfor i = 1:10000
result(i) = myfunc(data(i));
end
or
parfor i = 1:10000
result(i) = myfunc(data(i).relevantpart);
end
I think, in both case all the data are copied into memory within each loop, and not just data(i) for loop i.
Am I right?
So I want to avoid this.
As far as I see, the only way to do this, if I have separate data variables, like data1, data2, data3, ..., data10000.
But this is very ugly, and to automatically genarate them outside the loop and use them inside the loop, you have to use the function 'eval', which is not recommended in general.
So what is the solution for this general data 'loading/using' problem?
  1 个评论
Stephen23
Stephen23 2019-9-25
"...you have to use the function 'eval', which is not recommended in general."
Not only is it a bad way to write code, eval doesn't really work inside parfor loops:
https://www.mathworks.com/help/parallel-computing/transparency.html

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回答（1 个）

Matt J
Matt J 2019-9-25
编辑：Matt J 2019-9-25
Am I right?
No. In the code you have shown, the struct array data will be sliced,
https://www.mathworks.com/help/parallel-computing/sliced-variable.html;jsessionid=84aac55b1cc24a4fe4b489b5ae20
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显示 1更早的评论
Matt J
Matt J 2019-9-25
编辑：Matt J 2019-9-25
The Code Analyzer should warn you if you are broadcasting a non-sliced variable.
Edric Ellis
Edric Ellis 2019-9-26
You can also view the amount of data sent to/from a parfor loop using ticBytes and tocBytes.

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