What is the for loop that I can use to do the following then save the results as .mat file?

What is the for loop that I can use to do the following then save the results as .mat file?

I have 30 iterations and in each iteration I want to save the following:

Image with size 120*120 *1* 6000

Labels with size: 1*6000

E= 1*6000

and I will repeat the 30 iterations for 12 experiments (12 run).

Which means in each run will get the above files 30 times

[Dyuman Joshi]

Do you want to save them in an excel file? If so, do you want separate files for each data-set - image, labels and E?

If not, then please specify.

How do you obtain this data and what is the data type of each object?

[Torsten]

Maybe a 12 x 30 x 120 x 120 x 1 x 6000 matrix for the images, a 12 x 30 x 6000 matrix for the labels and a 12 x 30 x 1 x 6000 matrix for E ?

[M]

@Torsten, Correct, E Variable (double) I need to save

[M]

@Dyuman Joshi, I want save them as .mat files for further analysis.

Answer 1

[Dyuman Joshi]

Preallocate arrays according to the final size and the data type and modify the arrays iteratively.

Use indexing to obtain the corresponding data.

[M]

@Dyuman Joshi I tried to use the indexing but if failed, there is a mistake but I can't figure, Then I tried to save each iteration for each run separately, But it was too slow process and not efficient at all.

Can you please suggest a code for the above variable with the a random dimensions

Thanks

[Dyuman Joshi]

@M, How are you running the 12*30 iterations? A double for loop?

[M]

@Dyuman Joshi

The 12 run will be run individually,

each run contains 30 iterations

Suggest for me (for loop) only for one run which contains 30 iteration, the result of each iteration:

Image with size 120*120 *1* 6000 4D double

Labels with size: 1*6000 double

E= 1*6000 double

The final image, Labels and E, should contain the all results of 30 iterations for one run

[Dyuman Joshi]

For loop for only 1 single run -

%number of iterations
iter = 30;

%preallocation
data_image = zeros(iter,120,120,1,600);
Labels = zeros(iter,1,600);
E = zeros(iter,1,600);

for k = 1:iter
    data_image(k,:,:,:,:) = newImage;
    Labels(k,:,:) = newLabels;
    E(k,:,:) = newE;
end

[M]

@Dyuman Joshi Thanks, But I have question please

If we don't know the number of image and we put initially 1000 like the following

data_image = zeros(iter,120,120,1,1000);

Then after run it was 5000, will the other 4000 be saved and the data_image will be updated or not?

[Dyuman Joshi]

Yes, the other 4000 will be saved, however, the process will be a bit slower as MATLAB will have to find continous memory to store new data from iteration 1001 onwards.

If you don't know the final size of the output, you can pre-allocate a cell array instead -

iter = 30;

C = cell(iter,1);

for k=1:iter
    C{k} = store_data;
end

And concatenate the data after the for loop (assuming data is compatible for concatenation)

[M]

@Dyuman Joshi Thanks the 2nd solution worked but when I tried to save the results I got the following:

Warning: Variable 'Images' was not saved. For variables larger than 2GB use

MAT-file version 7.3 or later.

What can I do in this case?

[Dyuman Joshi]

@M - Does your PC have a 64 bit processor?

Also, check the setting of version of MAT-Files in your MATLAB - https://in.mathworks.com/help/matlab/import_export/mat-file-versions.html

Make sure the selected version is MAT-File Version 7.3