Use tfest within parallel loop

I am trying to use the function tfest to estimate a transfer function from frequency response data (frd) within a parlor loop. I am running into transparency violation issues within the tfest function and am getting the following error:

 Error using tfest (line 94)
    Transparency violation error. See Parallel Computing Toolbox documentation about Transparency

To the best of my knowledge the variables I am using are defined correctly as the tfestimate function does not have any transparency issues a few lines earlier in the code.

Thank you for any advice. The relevant code snippet is shown below:

 parfor i = 1:128
    len = LENGTH(i,k);
    Input = reshape(INPUT(i,k,1:len),[len,1]);
    exp_data = reshape(OUTPUT(i,k,1:len),[len,1]);
    time = reshape(TIME(i,k,1:len),[len,1]);

    fs = 50;  % Hz
    minFreq = 0.1;  % The minimum frequency that the fit is performed from
    maxFreq = 3.5;  % The maximum frequency that the fit is performed to
    np = 2;  % Force number of poles in the estimated transfer function
    iodelay = NaN;  % Initialize estimated pure delay in the system

    f = linspace(minFreq,maxFreq,1024);
    Txy = tfestimate(Input,exp_data,[],[],f,fs);
    measSysPhase = (180/pi)*phase(Txy);
    measSysMag = mag2db(abs(Txy));

    % Estimated transfer function fit to frequency data
    TxyData = frd(Txy,2*pi*f);
    estSys = tfest(TxyData,np,[],iodelay);
end

[Roman Schlieper]

put tfest into a function

Answer 1

[Sean de Wolski]

assign the output back to a cell array

estSys{i} = tfest(...)