help, error message: Subscripted assignment dimension mismatch.

hi, I am a very new in MatLab, I am working in MatLab R2017a on Win 10, it's a CNN example, this is the code:

% working path
path( path, 'C:\Users\mlerma\Documents\MATLAB\thesis');
cd C:\Users\mlerma\Documents\MATLAB\thesis

%%prepare
% currentFolder = pwd ;
clear ; close all ; clc ;
%%Load image 
imsetTrain = imageSet('images','recursive');

%%Display Sampling of Image Data
numClasses = size(imsetTrain,2);
imagesPerClass = 20;
imagesInMontage = cell(imagesPerClass,numClasses);
for i = 1:size(imagesInMontage,2)
    imagesInMontage(:,i) = ...
        imsetTrain(i).ImageLocation(randi(imsetTrain(i).Count, 1, ...
        imagesPerClass));
end

montage({imagesInMontage{:}},'Size',[numClasses,imagesPerClass]);
title('Imagenes de Ejemplo')

%%Prepare the data for Training
% Read all images and store them in a 4D uint8 input array for training,
% with its corresponding class

trainNames = {imsetTrain.Description};
XTrain = zeros(720,480,3,sum([imsetTrain.Count]),'uint8');
TTrain = categorical(discretize((1:sum([imsetTrain.Count]))',...
    [0,cumsum([imsetTrain.Count])],'categorical',trainNames));

j = 0;
tic;
for c = 1:length(imsetTrain)
    for i = 1:imsetTrain(c).Count
        XTrain(:,:,:,i+j) = read(imsetTrain(c),i);
    end
    j = j + imsetTrain(c).Count;
end
toc;

the error is en line:

 XTrain(:,:,:,i+j) = read(imsetTrain(c),i);

the message error is:

"Subscripted assignment dimension mismatch."

someone can help me??

thks in advanced

Angel

Answer 1

[Jan]

Use the debugger to examine the problem. Type this in the command window:

dbstop if error

Now run your code again until it stops at the error. Now check this:

size(XTrain(:,:,:,i+j))
size(read(imsetTrain(c),i))

Are they equal? If not, the assignment cannot work.

Perhaps you want:

k = imsetTrain(c).Count
XTrain(:,:,:, j:j+k-1) = read(imsetTrain(c),i);
j = j + k;

? Due to the lack of comments the readers (and you in some month) can only guess, what is intented.

Answer 2

[angel lerma]

hello Jan: you are rigth the values were different, so I fix it and these part work fine.

A lot of thaks...... Best regards... Angel

[Szillat]

Sorry, but how do you fix it? I put:

    j = 0;
tic;
for c = 1:length(imsetTrain)
    for i = 1:imsetTrain(c).Count
        XTrain(:,:,i+j) = read(imsetTrain(c),i);
    end
    j = j + imsetTrain(c).Count;
end
toc;

but it doesn't work