Problem In parfor loop

Question

Amit 2023-12-24

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2063697-problem-in-parfor-loop

评论： Matt J 2023-12-24

Hello All.

Here, k is image matrix with size of 2920x3756x501; 501= frame number. I want to get the intensity profile for all of these frames from the the specific X and Y co-ordinates value. In 2nd for loop, I was trying to align signals. I was trying the computation in parfor lop for both of the for loop. Getting continoulsy error , sometimw showing warning of broadcast variable, or sometime I am getting empty matrix D.

Assistance is genuinely appreciated !!!

Thank you

function [D] = ReducedData_DelayShift_Calculate(x_coordinates, y_coordinates,c_ref,num_frames)
% Initialize a matrix to store improfile data
improfile_data_matrix = [];
D  = zeros(1,num_frames);
k = load("reduced_data.mat");
for i = 1:num_frames
    % Extract the i-th frame from the image matrix
    current_frame = k.images_resized(:, :, i);
    % Compute the improfile
    improfile_data = squeeze(improfile(current_frame, x_coordinates, y_coordinates));
    % Append the improfile data to the matrix
    improfile_data_matrix = [improfile_data_matrix improfile_data(:,1)];
end
for i = 1:num_frames
    current_frame = improfile_data_matrix(:, i);
    [~ ,~ ,D(i)] = alignsignals((c_ref(:)),(current_frame(:)),Method="xcorr");
end
end

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Matt J 2023-12-24

sometime I am getting empty matrix D.

That most likely means that num_frames=0.

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Answer 1

Matt J 2023-12-24

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2063697-problem-in-parfor-loop#answer_1377037

编辑：Matt J 2023-12-24

在 MATLAB Online 中打开

I would get rid of the first for-loop and use interp3

function [D] = ReducedData_DelayShift_Calculate(x_coordinates, y_coordinates,c_ref,num_frames)
 
k = load("reduced_data.mat");
[xq,zq]=ndgrid(  linspace( x_coordinates(1), x_coordinates(2),2000 ), 1:num_frames  );
yq=repmat( linspace( y_coordinates(1), y_coordinates(2),2000 )'    ,1,width(xq));
improfile_data_matrix = ...
    reshape( interp3(k.images_resized, xq(:),yq(:),zq(:))   ,[],num_frames);
 D  = zeros(1,num_frames);
 parfor i = 1:num_frames
    current_frame = improfile_data_matrix(:, i);
    [~ ,~ ,D(i)] = alignsignals(  c_ref(:), current_frame(:) ,Method="xcorr");
 end
 
end