my code inside a parfor loop is getting longer and longer and I would like to split it up. Having parts of the code saved in different script files seems logical and very attractive and since it doesn't change anything except where the code is saved it seems like it should work. But it doesn't.
I get the usual "Transparency violation error".
The problem seems typical but I did not find this question asked or answered anywhere.
Below is a small working example.
(Yes, this could be made as a function. But in case of many more Input and Output variables this becomes really ugly imo and probably also slower due to communicating the arguments)
C = NaN(10,1); %Result vector
parfor loop = 1:10
a = 1;
b = 2;
MFile_Test %Run the m-file which contains only one line:
% c = a + b;
C(loop)=c;
end
the MFile_Test is a script just containing the line one line c = a + b.
I am beginning to understand why parallel computing has an issue here but not how to solve it. Since this would be possible without any problem if I just had the line c = a + b inside the parfor file I cannot belief there is no simple way to solve this (e.g. in the worst case something like tell matlab to load the text from another file and run it as code here and now).
If there are alternative ways to structure my code without using the script files (and, if possible, without using only functions ;)) I would appreciate such comments as well, of course.
Many thanks, Daniel
parfor has various constraints that make using scripts inside the loop generally a bad option. The main constraint is that the text of the parfor loop must be analysable to see what new variables might be created - this is referred to as "transparency" in the doc. Try using a function instead.