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Walter Roberson


43 585 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
How to compare two matrix?
nnz(A == 1 & B == 3)

3 minuter ago | 0

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....

ungefär 2 timmar 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 ...

ungefär 2 timmar 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...

ungefär 5 timmar ago | 0

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...

ungefär 5 timmar 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

ungefär 5 timmar 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...

ungefär 6 timmar 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...

ungefär 6 timmar 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...

ungefär 6 timmar 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 ...

ungefär 6 timmar ago | 0

| accepted

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...

ungefär 7 timmar ago | 1

| accepted

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...

ungefär 8 timmar ago | 1

| accepted

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...

ungefär 8 timmar 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...

ungefär 15 timmar 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...

ungefär 18 timmar 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...

ungefär 19 timmar 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...

ungefär 23 timmar ago | 0

| accepted

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...

en dag 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...

en dag ago | 0

| accepted

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...

en dag 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 dagar ago | 0

Answered
how to change axis of a matix?
[X, Y, Z]=ndgrid(1:90,1:3:120,1:40); C = round(ceil(Y./Z)); N = accumarray([X(:), C(:)], M(:), [], @mean, nan); sur...

2 dagar ago | 0

Answered
Why do I have "License checkout failed" problem on MATLAB 2017b on Ubuntu 17.10 after I activate MATLAB?
error -8: corrupt license file, or license server hostid not same as license file https://www.mathworks.com/matlabcentral/answer...

2 dagar ago | 0

Answered
Writing matrix in text file to serial port
The reason is that those routines do not exist until R2018b and r2019a. Furthermore, readmatrix and writematrix are for deali...

2 dagar ago | 0

Answered
Return if No Solution
You can test rank(A) . If it is < n then no solution is possible. However, there are full rank matrices for which the matrix is...

2 dagar ago | 0

| accepted

Answered
How to show projct
You can use questdlg() or menu() to get the user to select between discrete choices. Or you can use uicontrol('style', 'popup')...

2 dagar ago | 0

Answered
Downsizing a struct with different data type fields
nfield = length(myfields); newStruct = cell2stuct(cell(nfield,1), myfields); for fieldCtr = 1 : nfield thisfield = myfiel...

2 dagar ago | 0

Answered
Max function working for a sample of images but not all
length(images) is defined as: if isempty(images) length <- 0 else length <- max(size(images)) end You can see that...

3 dagar ago | 0

Answered
How to create a single table that shows every iteration
f= @(x) 33.33-5/3*x^2; %function of shear force x1=0; %location of support A x2=6; %location of maximum linear distributed f...

3 dagar ago | 0

Answered
Loop overwriting previous file
for n = 1:total_images_binary binary_Images=fullfile(image_folder_binary, filenames_bin(n).name) ; % its will specify image...

3 dagar ago | 0

| accepted

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