Variable in PARFOR

Hi

I have a loop in my code for calculating a matrix that index of matrix, determined in loop. for example:

 for ii=1:100
   pos=find(A==ii);
  .
  .
  .
  Z(:,pos)=Z(:,pos)+...
  .
  .
  .
 end

which A is another matrix. When I try to use PARFOR, an error occured for variable pos. I read PARFOR help in matlab, but I didn't get any idea how can I correct that. can anyone help me to write correct code for PARFOR?

Answer 1

[Walter Roberson]

Including the error message would help.

My speculation is that the analyzer is not able to determine that you are "slicing" Z in non-overlapping ways.

If so, then I do not know enough about PARFOR to be able to suggest a work-around.

[rahman]

Error: The variable Z in a parfor cannot be classified.

[Walter Roberson]

Are you initializing Z outside of the loop? Is the value of Z needed after the loop?

[rahman]

Yes. Befor loop started I initialized Z=zeros(N).

Yes. I use Z after loop

Answer 2

[Konrad Malkowski]

What are you trying to do with Z variable? Do you use it to accumulate some values (reduction variable) across all iterations? Or, do you update a single column of Z in each iteration? I would need more information on this loop and variable in order to help you.