UnableToRe​solveHidde​nFunction

I'm calling a function that I stored in a structure as a function handle. I get the following error

    Unable to find function @(p1)forwardsModel(params) within /media

/cogneuro/fit3.m

with identifier:

    identifier: 'MATLAB:dispatcher:UnableToResolveHiddenFunction'

The structure is created in file fit3.m:

    function result = fit3
    for i=1:N
      for j=1:M
          params = createParameters(i,j);
          result{i}(j).forwardsModel = @(p1)forwardsModel(params,p1)
          [result{i)(j).optimP, result{i}(j).optimNLL] = ...
              fmincon( result{i}(j).forwardsModel, zeros(1,NP) );
      end
    end
    return 
    
    function negloglikelihood = forwardsModel(p,u)
        ... % calculate likelihood of model
    return

I create the functions like this

    result = fit3;    % this works fine
    save fit3_functions  result   % this works fine

then later I retrieve the fits

    load fit3_functions   % this works fine too

The I call

    x = result{1}(1).forwardsModel(p0_actual);

and get the above error. I am not sure exactly what conditions reproduce this problem, as it sometimes works.

Any thoughts on

• what this error means,
• why it might be triggered in this situation, and
• how I might avoid it happening?

[Guillaume]

does loading with:

matcontent = load('fit3_functions');
result = matcontent.result;
x = result{1}(1).forwardsModel(p0_actual);

fix the problem?

If not, what is the output of

functions(result{1}(1).forwardsModel)