Undefined function or variable using parfor in matlab - matlab

Question

I'm unable to execute the following code:
parallel_mode = true; %To process multiple images at the same time
parallel_degree = 4; %Number of threads that will be created
if parallel_mode
if matlabpool('size') == 0
matlabpool(parallel_degree);
elseif matlabpool('size') ~= parallel_degree
matlabpool close;
matlabpool(parallel_degree);
end
end
%Loading dictionary
try
load(dictionary_path);
catch
error(['Was impossible to load the dictionary in path: ' dictionary_path ', Please, check the path. ' ...
'Maybe you should use dictionary_training function to create it.'])
end
%% Processing test images
test_images = dir([test_im_path, pattern]);
num_test_images = size(test_images,1);
%Pre-allocating memory to speed-up
estimated_count = zeros(1,num_test_images);
true_count = zeros(1,num_test_images);
estimated_upper_count = zeros(1,num_test_images);
estimated_lower_count = zeros(1,num_test_images);
true_upper_count = zeros(1,num_test_images);
true_lower_count = zeros(1,num_test_images);
%Calculating dimensions of the image subregion where we can count
im_test = imread([test_im_path test_images(1).name]);
dis = round(patch_size/2);
dim_x = dis:size(im_test,2)-dis+1;
dim_y = dis:size(im_test,1)-dis+1;
toGaussian = fspecial('gaussian', hsize, sigma);
parfor a=1:num_test_images
disp(['Processing image #' num2str(a) ' of ' num2str(num_test_images) '...']);
im_test = imread([test_im_path test_images(a).name]);
[~, name, extension] = fileparts(test_images(a).name);
im_ground_truth = imread([ground_truth_path name 'dots' extension]);
disp('Extracting features...');
features = extract_features(im_test, features_type, dic_signal, sparsity, patch_size, mean_rem_flag);
features = full(features); %ND-sparse arrays are not supported.
%Re-arranging features
features = reshape(features', size(dim_y,2), size(dim_x,2), dic_size);
%Normalizing features
max_factors_3D = repmat(max_factors_depth, [size(features,1), size(features,2)]);
max_offset_3D = repmat(max_offset_depth, [size(features,1), size(features,2)]);
features = (features-max_offset_3D)./max_factors_3D;
%%Some stuff
....
end
When i execute it i get:
Undefined function or variable 'dic_signal'.
when it arrives to the extract_features function. However, in the single thread version (with for instead of parfor) it works correctly.
Someone can give me any hint?.
Thank you.
EDIT:
dic_signal is defined and correctly loaded in load(dictionary_path);

Answer 1

I suspect the load command doesn't load the variables in the workers workspace, only on your MATLAB instance workspace, which is why it works in a normal for loop, but not with a parfor loop. You might want to try instead:
pctRunOnAll load(dictionary_path)
to ensure the correct data is loaded into the workspace of each of the workers.