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Walter Roberson


41,685 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
Matrix Randomize with order
There cannot be any solution to this problem. Consider that you have 21 columns. Each "line" (including columns) can have a ma...

1 hour ago | 0

Answered
distance between randomly selected nodes
xt = [CC.xd]; yt = [CC.yd]; distances = squareform( pdist([xt(:), yt(:)]) );

2 hours ago | 0

Answered
Functions: converting Fahrenheit to Celsius
When you define a function inside a script, the function cannot have the same name as the script .m file.

2 hours ago | 1

Answered
Plot different functions in the same graph?
plot first function hold on plot second function h3 = plot third function for t = 1 : whatever calculate new X and Y to...

2 hours ago | 0

Answered
Matrix dimensions must agree error when converting from jg2 to tiff
fileparts returns character vectors, not string objects. baseFileNameYeet is a character vector. You are trying to do arithmetic...

2 hours ago | 0

Answered
How to integrate within a loop with an interpolating function?
You have x=(-4:0.05:4); y=(-4:0.05:4); [X,Y]=meshgrid(x,y); those put specific numeric arrays into X and Y. Z1=3*(1-X).^2.*...

2 hours ago | 0

Answered
Plot won't show up for plotting error for SOR method
err = zeros(1,m); for w = 1 : m x = sor1_fn(A,b,w,X0,n_iter); err(w) = norm(x_true - x); end plot(1:m, err);

20 hours ago | 0

Answered
Importing data from a file in a specific way
fileID = fopen(file, 'r'); formatSPec = '%f %f %f'; sizeA = [3 Inf]; %notice not [Inf 3] A = fscanf(fileID, formatSpec, siz...

20 hours ago | 0

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Answered
Not enough memory to open .nii file
.nii files are binary files. You should not be trying to edit them in MATLAB. You should use https://www.mathworks.com/help/imag...

22 hours ago | 0

Answered
Extract certain rows of matrix if they have a certain number
mask = ismember(M(:,4), 17:21); afternoon_M = M(mask,:); There are other ways to write the test, such as mask = M(:,4) >= 17...

23 hours ago | 1

Answered
Unable to perform assignment because the left and right sides have a different number of elements, Fisheriris
gscatter() returns a number of handles equal to the number of groups it detects. Since you appear to have 8 groups, it will prob...

24 hours ago | 0

Answered
How to write binary numbers in a txt file?
The result of dec2bin is a char array. A char array is a single parameter as far as %s is concerned. If you are using R2016b or...

1 day ago | 0

Answered
How to define a variable form a value in for loop?
This is really not recommended If you insist on doing this not-recommended thing

1 day ago | 0

Answered
Can I specify C matrix with tf2ss?
You cannot specify the C matrix in a tf2ss() call. It always calculates the C matrix based upon the numerator and denominator. L...

1 day ago | 1

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Answered
How to plot function part by part?
duration = 10; Fs = 20; %samples per second secs_per_plot = 2; data = randi([-5 5], 1, duration*Fs); %example data fo...

1 day ago | 0

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Answered
How does the operation take place for, b (2:6, 2:6) = b(1:5, 2:6) + b(3:7, 2:6) + b(2:6, 1:5) + b(2:6, 3:7); , row-wise manner ?
The first code extracts all the various subsets of the b array before doing any assignments. For example b(3,4) is part of each ...

1 day ago | 1

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Answered
Undefined function 'initializeParameters' for input arguments of type 'double'. This is what i get when i run. Please help
https://www.mathworks.com/matlabcentral/fileexchange/69238-hyperspectral-image-classification You need to install that. If you ...

1 day ago | 0

Answered
Index in position 2 exceeds array bounds (must not exceed 3).
Because g includes 4, at some point you are going to try to access l(1,4) . However you only initialize l to (3,3) so l(4,:) and...

1 day ago | 0

| accepted

Answered
how to append a mat file
You cannot do that with save() Have a look at https://www.mathworks.com/help/matlab/ref/matfile.html

1 day ago | 0

Answered
Passing values to Bash script
Example: cmd = sprintf('alpha=%d beta=%d ls | head -$beta | tail -$alpha', alpha, beta); system(cmd)

1 day ago | 0

| accepted

Answered
UiTable HTML not working
uitable for app designer is not based upon the same underlying technology, and does not support html for coloring. I do not kn...

1 day ago | 0

Answered
Array indices must be positive integers or logical values error
You initialize nT to 0. You access wk(nT) but nT is still 0. You need to move the increments of nT to before you use nT as ind...

2 days ago | 0

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Answered
Finding value of x using integral
The right hand side is a constant. Compute it first. Suppose I refer to that as RHS. Then you can fsolve(@(Xa) integral(@(XA...

2 days ago | 0

Answered
How to convert 1x21 array to table
lambda_table = table(labmda(:), 'VariableNames', {'lambda'});;

2 days ago | 0

Answered
How to calculate monthly data from daily rainfall data in a time-seris 3-dimensional matrix?
mat2cell() to break the 17 x 22 x 332 up into cell arrays 17 x 22 x number_of_days_in_month . Then you can cellfun(@(M) sum(M,3)...

2 days ago | 0

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Answered
fsolve problem
It is not possible to set bounds for fsolve() . You can set the FunValCheck option for fsolve() to tell it to check each iterati...

2 days ago | 0

Answered
Can I divide a linear array by a number which larger than its size ?
Next20 = @(V) ceil(length(V)/20) * 20; Interp20 = @(V) interp1(V, linspace(1, length(V), Next20(V))); Split20 = @(V) mat2cell(...

2 days ago | 0

Answered
Sending <ESC> T over Serial port to Scale
fprintf(s, '%cT', 27) you might also need to send a terminator

3 days ago | 0

Answered
MATLAB code that execute exp function without using the exp inbuilt function
See https://www.mathworks.com/help/fixedpoint/ref/cordiccexp.html

4 days ago | 0

Answered
Index exceeds the number of array elements (2) Error
Your assignment to h(i) after the if expects vt(i) to have been assigned to. However, if the if condition was false, then the as...

5 days ago | 0

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