I encountered an 'invalid use of operator' error message.

I encountered an 'invalid use of operator' error message when excuted this below.

load(fullfile(E:\charite\Data\EGCG_Round3\MRE\MouseAtlasReg\ProcessedShort\20241024_sl_MRE_Day18_Cage1_3505_MRE\mreCubes1,'ventricles.mat'));

Answer 1

[Harald]

Hi,

you need to place single or double quotes around the path. With single quotes:

load(fullfile('E:\charite\Data\EGCG_Round3\MRE\MouseAtlasReg\ProcessedShort\20241024_sl_MRE_Day18_Cage1_3505_MRE\mreCubes1','ventricles.mat'));

If you are just getting started with MATLAB, you may find the MATLAB Onramp helpful.

Best wishes,

Harald

[Shiyue]

Thanks!!!! It works, I will take the course of MATLAB Onramp later!!

[Shiyue]

Hi, I’ve run into another issue: 'Arrays have incompatible sizes for this operation' when I execute the code below. Thanks again for your assistance!

load(fullfile('E:\mreCubes1','ventricles.mat'));

load(fullfile('E:\mreCubes1\rois','WholeBrain_115cut.mat'));

WholeBrain_115cut_noVentricle = and(WholeBrain_115cut, ~ventricles);

save(fullfile('E:\mreCubes1','WholeBrain_115cut_noVentricle'),'WholeBrain_115cut_noVentricle')

[Steven Lord]

I assume the line where you call and is where the error occurs. If that's not correct, or if you ask about other errors in the future, please show the full and exact text of the error message (all the text displayed in red in the Command Window, and if there are any warning messages displayed in orange, please show us those too.) The exact text may be useful and/or necessary to determine what's going on and how to avoid the warning and/or error.

If that assumption is correct, please show us the sizes of the two variables you're using as inputs to and. You can do so using the whos function immediately before the line that throws the error. If the variables have more dimensions than whos can show in its output (if one of the variables has 5 or more dimensions, like z in the example below) please show the size of that variable as well.

clear all
x = 1;
y = rand(2);
z = ones(2,3,4,5,6);
whos

  Name      Size            Bytes  Class     Attributes

  x         1x1                 8  double              
  y         2x2                32  double              
  z         5-D              5760  double              

size(z)

ans = 1×5

2 3 4 5 6

<mw-icon class=""></mw-icon>

<mw-icon class=""></mw-icon>

The and function requires its inputs to be compatibly sized.

and([-1 0 1], [2;3;4;5])

ans = 4x3 logical array
   1   0   1
   1   0   1
   1   0   1
   1   0   1

If they're not:

and(ones(2), ones(3)) % What does it mean to and together a 2-by-2 and a 3-by-3?

Error using &
Arrays have incompatible sizes for this operation.

[Shiyue]

Hi, here is the full and exact text of the error message, now it shows "Dot indexing is not supported for variables of this type." o(╥﹏╥)o

>> GenerateMasksWithoutVentricles

E:\charite\Data\EGCG_Round3\MRE\MouseAtlasReg\ProcessedShort\20241024_170015_20241024_sl_MRE_Day18_Cage1_3505_MRE_1_1\mreCubes1\TransformParameters.0_Par0025affine.txt\rois

Dot indexing is not supported for variables of this type.

Error in GenerateMasksWithoutVentricles (line 53)

WholeBrain_115cut_noVentricle = and(WholeBrain_115cut.mat, ~ventricles.mat);

[Shiyue]

Here is the full text

pathDefault = 'E:\charite\Data\EGCG_Round3\MRE\MouseAtlasReg\ProcessedShort\20241024_170015_20241024_sl_MRE_Day18_Cage1_3505_MRE_1_1\mreCubes1';

listing = dir(pathDefault);

listing(1:2) = [];

for iFolder = 1 : length(listing)

currentPath = fullfile(listing(iFolder).folder, listing(iFolder).name);

path = fullfile(currentPath,'rois'); %change back to rois

disp(path);

if strcmp(listing(iFolder).name,'results')%doesnt run the loop for this folder

continue;

end

load(fullfile('E:\mreCubes1', 'ventricles.mat'));

ventricles_dilated1pix=imdilate(ventricles,strel('disk', 1));

save(fullfile ('E:\mreCubes1', 'ventricles_dilated1pix'),'ventricles_dilated1pix');

load(fullfile('E:\mreCubes1','ventricles.mat'));

load(fullfile('E:\mreCubes1\rois','WholeBrain_115cut.mat'));

WholeBrain_115cut_noVentricle = and(WholeBrain_115cut.mat, ~ventricles.mat);

save(fullfile ('E:\mreCubes1', 'WholeBrain_115cut_noVentricle'),'WholeBrain_115cut_noVentricle')

[Harald]

Hi,

you should not work with the .mat files in that line, but with the variables that you have imported from them:

If the variables are named the same as the .mat files, this would be

WholeBrain_115cut_noVentricle = and(WholeBrain_115cut, ~ventricles);

like you have shown in an earlier version.

In general, it will be

varC = and(varA, ~varB);

Best wishes,

Harald

Answer 2

[dpb]

load(fullfile('E:\charite\Data\EGCG_Round3\MRE\MouseAtlasReg\ProcessedShort\20241024_sl_MRE_Day18_Cage1_3505_MRE\mreCubes1','ventricles.mat'));

You forgot the tic marks around the folder string; MATLAB tried to evaluate the \ as the ldivide, .\ operator.

[Harald]

Strictly speaking, mldivide (\) rather than ldivide (.\).

Answer 3

[Image Analyst]

You forgot quotes. Corrected:

load(fullfile('E:\charite\Data\EGCG_Round3\MRE\MouseAtlasReg\ProcessedShort\20241024_sl_MRE_Day18_Cage1_3505_MRE\mreCubes1','ventricles.mat'));

or simply don't use fullfile(), unless you need to change the folder or basefilename and are using variables for that:

load('E:\charite\Data\EGCG_Round3\MRE\MouseAtlasReg\ProcessedShort\20241024_sl_MRE_Day18_Cage1_3505_MRE\mreCubes1\ventricles.mat');

[Shiyue]

Thanks for your answer; it worked!