Question on a simple "parfor loop"

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harry wang 2015-11-23

0
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关闭： MATLAB Answer Bot 2021-8-20

Hi There,

I have a simple parfor loop as belows

c=1;
a=0;
parfor i=-90:90
c=i+91;
a(c)=3;
end

I thought in this way, each iteration is independent and satisfy the rule of parallel computing, but i still get an error message " The variable a in a parfor cannot be classified". Any one could let me know the reason and how to fix the code?

Thanks.

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Answer 1

Walter Roberson 2015-11-24

1
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parfor i=-90:90
  a(i+91)=3;
end

The parfor index variable must appear directly in the indexing expression, not as a variable computed based upon the indexing expression. This is a limitation on parfor to allow it to do static analysis.