Ones function printing out

Can anyone tell me why my ones function is causeing my code to print even though it has a semi colon? I commented everything else out to narrow it down to the ones function. I already reinstalled matlab but nothing seems to be working

getX1();

Error using load
Unable to find file or directory 'mnist.mat'.

Error in solution>getX1 (line 7)
load('mnist.mat', 'images'); % Load 'images' variable from 'mnist.mat'

function X1 = getX1()
clc;
close;
clear;
load('mnist.mat', 'images'); % Load 'images' variable from 'mnist.mat'

num_images = size(images, 1);
image_size = 26 * 26; % Adjusted image size

X1 = ones(num_images, image_size + 1); % Initialize X matrix with bias column

for i = 1:num_images
    %Crop 1-pixel border
    image_cropped = images(i, 2:end-1, 2:end-1);
    %Flatten image, normalize, and append 1
    image_flat = double(reshape(image_cropped, 1, [])) / 255;
    image_with_bias = [image_flat, 1];
    % Update X matrix
    X1(i, :) = image_with_bias;
end

% size of X matrix
fprintf('Size of X matrix: %d rows x %d columns\n', size(X1, 1), size(X1, 2));
end

[Walter Roberson]

We need the .mat file to test with.

[Walter Roberson]

It would be interesting to see the output of

which -all ones

[Zachary David]

sorry it says its too large

[Zachary David]

[Walter Roberson]

which -all ones

please.

It is a little suspect that images is uint32 but that you are dividing by 255

[Zachary David]

im assuming you are asking which ones function? X1 = ones(num_images, image_size + 1);

we were told we needed to normalize the data and we were told to use 255

[Walter Roberson]

At the MATLAB command line, please give the command

which -all ones

and tell us the result.

This will give us information about whether possibly a different ones function is being invoked.

[Stephen23]

"im assuming you are asking which ones function?"

Yes. Please run this code:

which -all ones

and show us exactly what it displays.

[Zachary David]

built-in (C:\Program Files\MATLAB\R2023b\toolbox\matlab\elmat\ones)

-this is what it gives me

[VBBV]

It seems you are running the script file getX1.m from a wierd location. Change its location to a different folder and run again

The path from the screenshot shows something like this

C:\users\zach1\OneDrive\...\Project1\mnist.mat\getX1.m

mnist.mat >> change this to a different name without a dot and check whether you still get that issue

[Walter Roberson]

@VBBV

That will not make any difference. mnist.mat is a valid directory name.

Answer 1

[Walter Roberson]

The ones is the output of your function. You are running the function by pressing the green Run button, which executes the function which returns X1 which then gets printed out automatically.

[Zachary David]

I know it is the output but why would it be printed out automatically when im not asking for that to happen. How do i stop it from printing out?

[Walter Roberson]

At the end of the code, insert

if nargout == 0
    clear X1;
end

Answer 2

[Star Strider]

The fprintf call will execute and print even if there is a semicolon at the end of that call.

X1 = rand(3,5);
fprintf('Size of X matrix: %d rows x %d columns\n', size(X1, 1), size(X1, 2));

Size of X matrix: 3 rows x 5 columns

Are you seeing that or something else?

.

[Star Strider]

The ‘Workspace’ window reports a (677 x 60000) double matrix called ‘ans’, the default variable name MATLAB uses. I suspect that it’s not being generated by the function, and it may be coming from somewhere else, althoough I can’t determine that from here.

What results if you preallocate ‘X1’ with zeros instead? You’re overwriting it in the loop, so the sort pf preallocation might not matter.

[Zachary David]

oddly the same thing

[Star Strider]

Do you mean a matrix of zeros now, or still a matrix of ones?

[Zachary David]

still a matrix of ones

[Zachary David]

i was thinking it might be coming from somewhere else too. Maybe my recycling bin

[Star Strider]

It’s coming from somewhere else in your code. I doubt if anything in the recycling bin is in any way active.

I don’t know how long your code is, however in the past when I needed to isolate something like that, I inserted:

fprintf('Stopped on line %d\n', line_nr)

return

and then moved those lines to various points in my code and then looked to see if the problem recurred. (I inserted the line number manually.) That helped me find the problem.

There are a collection of debugging tools available, however they might not be helpful in tracking down a line that prints a matrix, and that’s all you want to do at the moment.