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Walter Roberson


43,594 total contributions since 2011

I do not do free private consulting. If you want to bring my attention to something, send a link to the MATLAB Answers location.

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Answered
'.' is not an internal or external command, nor is it a runnable program or batch file
You are trying to run Linux code on ms windows. You will need to change the / in the system() command to \

7 hours ago | 1

Answered
how to open .mat file in matlab?
You are calling importfile1() without passing in a parameter. You cannot run importfile1() just by clicking the green Run butto...

8 hours ago | 1

| accepted

Answered
Using strfind to find character index in word
Guess1 = 'e'; HangWord = "each"; index = strfind(HangWord, Guess1);

8 hours ago | 0

Answered
Is vaderSentimentScores available in R2019a
No, it was introduced in R2019b. See https://github.com/cjhutto/vaderSentiment for python library and https://github.com/nunoac...

9 hours ago | 0

Answered
Index Exceeds Number of Array Elements (1)? Line(5)
Line 5 is fid=fopen('Lab1_Problem1.txt'); In order to receive an index out of range in that line, you would have to have a var...

11 hours ago | 0

Answered
How to crop multiple images?
Yes, imageSet requires the Computer Vision Toolbox. imageDir = 'D:\Masters Thesis\ssss'; dinfo = dir(imageDir); dinfo([dinfo....

12 hours ago | 0

Answered
How put a gif on GUIDE
GUIDE does not directly support playing GIFs. What you can do is read the frames of the GIF and store them in an accessible pl...

12 hours ago | 0

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Answered
plotting graph and mark points
d = xlsread('FaceFour_TRAIN.xlsx'); plot(d); hold on idx = find(d>0.04); pointsize = 20; scatter(idx, d(idx), pointsize, 'b...

13 hours ago | 0

Answered
how plot only show the value which I selected
Location = menu('Please select a loaction',LocationID); assigns to a variable named Location with an upper-case L fprintf('On ...

13 hours ago | 0

Answered
How to compare two matrix?
nnz(A == 1 & B == 3)

13 hours ago | 0

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Answered
Optimisation of a filter knowing input and output
First order low pass filters only have a very small number of parameters. If you look at the discrete description at https://en....

15 hours ago | 0

Answered
How to avoid the user insert a number with a wrong value
Preventing the user from entering a number that is invalid for the currently selected base is complicated. It requires checking ...

15 hours ago | 0

Answered
Help I can't get my code to execute
xd = (-1)*(r)*(thd)*sin(theta)-(numer/(2*sqrt(denom))); where denom = ((c^2)-(r^2)*(theta)); but denom can be negative, and s...

17 hours ago | 1

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Answered
I'm using old matrix in given data and adding user data to add onto old matrix. Example Days(16x1), Location(16x5), LocationID(1x5) and when user inputs a day its supposed to add onto Days, Same with new location and LocationID.
Days2(D2) D2 contains day numbers such as 52 and 60, but there are only 16 (before additional data) or 21 (after additional dat...

18 hours ago | 0

Answered
Install new info.
LocationID(6) = "some new string" Days(17:21) = vector of 5 day numbers Ice(17:21,6) = vector of 5 numeric values

18 hours ago | 0

Answered
I wanna save text as txt file in my desktop or any location I choose
Text='hello'; [file, pathdir] = uiputfile('text. Txt'); if isempty(file); return; end %user cancel fullname = fullfile(pat...

19 hours ago | 0

Answered
How to display all decimal numbers for floating numbers?
There are an infinite number of decimal 0's at the end of any floating point number, so it is not possible to make it display al...

19 hours ago | 0

Answered
Saving an audio file in .wav format
https://www.mathworks.com/help/matlab/ref/audiowrite.html https://www.mathworks.com/help/dsp/ref/dsp.audiofilewriter-system-ob...

19 hours ago | 0

Answered
create matrix with integral
P = 5; for m = 1:P; for n = 1:P; L(n,m) = integral( @(x) fun(x,n).*fun(x,n)), -1, 1); end end function ...

19 hours ago | 0

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Answered
Can someone expalin the if statement and the code below it and what does taggedCars doing?
If no blobs are detected then regionprops() would return an empty struct, and [stats.Area] would be empty. In such a case you do...

20 hours ago | 1

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Answered
Opening R2018b .m files in R2019b
Quick Access gives you access to paths that were either used "recently" or that you marked as favourite. It does not, however, c...

21 hours ago | 1

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Answered
How to send large numbers via UDP?
What is coding them as utf16 ? In any case, use native2unicode() to convert raw bytes that are UTF8 or UTF16 into MATLAB charac...

21 hours ago | 0

Answered
Can't connect blocks in simulink
The AC source you have used is https://www.mathworks.com/help/physmod/sps/powersys/ref/acvoltagesource.html from Simscape Electr...

1 day ago | 0

Answered
Error using accumarray First input SUBS must contain positive integer subscripts.
You also posted this in https://www.mathworks.com/matlabcentral/answers/480253-how-to-change-axis-of-a-matix#comment_745999 a...

1 day ago | 0

Answered
Relationship between Sigma and grid size in imgaussfilt3
If "number of grid cells" refers to the size of the filter, then according to the documentation, % 'FilterSize' - Scalar...

1 day ago | 0

Answered
Reference to non-existent field 'NIQE'.
When there are no .png images in the subdirectory your_results of the current directory, then scores will be returned as an empt...

1 day ago | 0

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Answered
Equality and inequality constraint
When you have an equality constraint, it is common to be able to get further by solving the equality for one of the variables an...

1 day ago | 0

| accepted

Answered
add the value of column from text file to the value to matrix
data = load('u.data'); [uni_user, ~, uni_user_idx] = unique(data(:,1)); [uni_item, ~, uni_item_idx] = unique(data(:,2)); rati...

1 day ago | 0

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Answered
How to choose only certain values my matrix answer
A=[400,563,674,904,789]; idx1 = find(A>=563, 1, 'first'); idx2 = find(A>=904, 1, 'first'); A(idx1:idx2) but I suspect what y...

2 days ago | 0

Answered
Activating MatLab on non-administrator Windows account?
Yes. However, you will have to install matlab to a directory that you have full write access to, as normally you need to run as ...

2 days ago | 0

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