Is it possible to use use `parfor` for parallel computing in Matlab in these codes?

Question

I am using parfor for parallel computing in Matlab. I am not familiar with this command. If that is possible, please look at my code below and tell me if I can write it with parfor. These errors and warnings are appear in Matlab Editor:

• The parfor loop cannot be run due to the way variable Dat is used. (when I comment line Dat.normXpj = normXpj(pj,:); This error is solved and other errors similar to the following error is appeared.

• The entire array or structure Bound is broadcast variable. This
  might result in unnecessary communication overhead.

  parfor pj = 1:size(normXpj,1)
  Dat.normXpj = normXpj(pj,:);
  
  if size(Dat.InitialGuess)==0
      X = (Bound(:,1)+(Bound(:,2)-Bound(:,1)).*rand(Nvar,1))';
  else
      X = Dat.InitialGuess;
  end
  
  [Xsqp, ~, FLAG,Options] = mopOPT(X,Dat);
  FEVALS = Options.funcCount;
  
  FES = FES+FEVALS;
  
  PSet(pj,:) = Xsqp;
  PFront(pj,:) = mop(Xsqp,Dat,0);
          if FLAG==-2
      disp('.......... Algo paso...');
  else
    F = PFront(pj,:);
    if Nobj==2
        plot(F(1,1),F(1,2),'*r'); grid on; hold on;
    elseif Nobj==3
  
     end
  end 
  end
  

Answer 1

The problem here is that it we can see that you're not using Dat in a way that is order-dependent, but the static analysis machinery of parfor cannot deduce that because of the way you're assigning into it. I think you can work around this by instead creating a whole new Dat for each iteration of the loop, like so:

Dat = struct('normXpj', rand(10,1), 'InitialGuess', 3);
normXpj = rand(10);
parfor idx = 1:10
    tmpDat = struct('normXpj', normXpj(:,idx), 'InitialGuess', Dat.InitialGuess);
    % use 'tmpDat'
    disp(tmpDat);
end

Answer 2

The answer is no, unfortunately. At line:

Dat.normXpj = normXpj(pj,:);

you assign a value to Dat.normXpj, but you have to know that in a parfor loop there can be multiple iterations executing at the same time. So what value should be used for Dat.normXpj ? Matlab cannot decide, hence your error.

More generally, your code looks quite messy. I suppose you want to use parfor to increase execution speed. Probably a more efficient option would be to use the profiler (see profile) to detect the bottlenecks in your code, and apply a correction if that's possible.

Best,