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Walter Roberson


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46,768 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 write this pseudocode in matlab?
https://www.mathworks.com/help/matlab/ref/graph.shortestpathtree.html

3 hours ago | 0

Answered
preallocate memory for a struct in a for loop
for i = size(filename,1) : -1 : 1 spectra(i).name = filename(i,1:end-4); spectra(i).value = readmatrix(filename(i,:));...

3 hours ago | 0

| accepted

Answered
Error matlab r2017b
You do not have read access to C:\Program Files\MATLAB\R2017b\toolbox\local\pathdef.m and possibly to other MATLAB files as well...

6 hours ago | 0

Answered
If I have to perform arithmetic encoding on a sequence such as "222101" where one of the digits is 0 , how do I solve the error "The symbol sequence parameter must be a vector of positive finite integers"?
In R2020a, you need to edit line 173 of arithenco to change if ~all(seq > 0) || ~all(isfinite(seq)) || ~isequal(seq, round(seq)...

6 hours ago | 0

Answered
I can't find the mistakes
desen_cercuri_Callback assigns to x01, y01 and so on, but tries to plot(x1,y1,z1,x2,y2,z2) -- notice the x01 vs x1. Note that y...

20 hours ago | 0

Answered
Adding two linear inequality constraints in Optimization toolbox
I refer you to https://www.mathworks.com/matlabcentral/answers/557419-constraint-function-in-optimization-toolbox#answer_459217...

20 hours ago | 0

Answered
Bit xor of row with the next row and the output is again xored with the next row
c = 245; A = [23 2 13;34 56 70;12 18 90]; a = []; [m, n] = size(A); a(1,:) = bitxor(c,A(1,:)); %Xor c with each element of...

20 hours ago | 0

Answered
If I change the folder names in the popup menu and i need to get the files in that folder to the list box and similar if i change to other folder , that folders files should come
ph = handles.YourPopup; lh = handles.YourListbox; selection_index = ph.Value; if ~isempty(selection_index) user_chosen_f...

21 hours ago | 0

Answered
How to numerically solve a differential equation with a dirac delta function ?
Use ode45 to solve the equation over the start time to time 1 (the place the dirac delta is located.) Do not use the if statemen...

21 hours ago | 0

Answered
Data String unreadable in uitable matlab
Your use of 'Nama' as a header suggets that you expect the column you are selecting to be character vectors -- names. However wh...

23 hours ago | 0

Answered
How to generate random numbers between min and max value with gevrnd?I
https://www.mathworks.com/help/stats/prob.normaldistribution.truncate.html truncate() the distribution. That will automatically...

1 day ago | 0

| accepted

Answered
Resampling Data using Interp1
load('BNI_processed.mat') input_forces = Force_arr(:,2); time_matrix = Force_arr(:,1); Fs = 100; last_time = ceil(time_matri...

1 day ago | 0

Answered
No appropriate method, property, or field 'Files' for class 'augmentedImageDatastore'.
Hack way: old_warning_state = warning('off', 'MATLAB:structOnObject'); temp = struct(augimdsValidation); warning(old_warning_...

1 day ago | 0

Answered
Understanding Precision in Matlab
You cannot do that with double precision. If you have the symbolic toolbox then: r = linspace(sym('5.047639467288342e+4'), sym...

1 day ago | 0

Answered
Identifying identical vectors within a cell array and then grouping/moving them into a different cell arrays
data = {[5]; [1,2,3,5,6]; [1,2,3,5]; [3,5,6]; [1,2,3,4,5,6]; [3,5,6]; [3,4,6]; [5,6]; [1,2,3,6]; [5,6]; [5,6]; [5,6]; [1,2,3,4,5...

1 day ago | 1

| accepted

Answered
2D array interpolation
Assuming that array is stored in data vals_to_find = [120 140]; nvals = length(vals_to_find); D = data(2:end,2:end); X = d...

1 day ago | 0

Answered
Extract each value from rows of excel sheet for 40 iterations
values = xlsread('Filename.xlsx'); for iteration = 1 : length(values) K = values(iteration); do something with K e...

1 day ago | 0

| accepted

Answered
Creat a big matrix by adding elements from smaller matrices
part1 = blkdiag(a,c,e,g, zeros(7,7)); part2 = blkdiag(zeros(7,7),b,d,f,h); K = part1 + part2;

1 day ago | 1

| accepted

Answered
Index exceeds the number of array elements (1).
If you subs in a particular value for lambda then after the subs() d2L contains only dy, and since you did not specify a variabl...

1 day ago | 1

| accepted

Answered
Running the Same code for Multiple Files in a Folder
indir = '.'; %path to input directory outdir = 'results'; %path to where to put the results if ~exist(outdir, '...

1 day ago | 0

| accepted

Answered
Can I keep the text of my delimiter or LineEnding when using readcell, readtable, etc.?
That is not possible using readtable() or readmatrix() or readcell() . You can pre-process the file: S = fileread(filename); ...

1 day ago | 1

| accepted

Answered
How to use histogram equalization for a given image, without including the black background ?
However, Matlab keeps (automatically) adding a black background to my images. I am not aware of even one image file format that...

1 day ago | 0

| accepted

Answered
breakpoints specification does not supported in lookup table matlab2014b
https://web.archive.org/web/20150212023953/http://www.mathworks.com/help/simulink/slref/ndlookuptable.html The n-D lookup tabl...

1 day ago | 0

Answered
Constraint function in optimization toolbox
function [c,ceq] = csp_advisor(TotalmassFlow) The constraint function is passed the current value of all of the variables -- wh...

1 day ago | 0

Answered
How to upgrade MATLAB R2020a
You cannot "upgrade" between releases, in the sense that there is no program that will take your r2019b matlab and modify some l...

2 days ago | 0

Answered
Why do I get this xlswrite error?
Either remove the keyword 'sheet' or else before the last input add the keyword 'range'. You can use positional arguments but as...

2 days ago | 0

| accepted

Answered
What is missing from MATLAB?
Ability to use a multidimensional logical array to substitute for multiple dimensions while still specifying other dimensions. ...

2 days ago | 0

Answered
Saveas Invalid Handle Error
edge() does not return a figure or any other type of graphic object. edge() returns a logical() array, and does not display the ...

2 days ago | 0

| accepted

Answered
Extract only numbers from a text file with Matlab
I recommend using regexp with named tokens and the 'names' option. For example parts = regexp(S, 'x="(?<x>[^"])"\s+y="(?<y>...

2 days ago | 2

| accepted

Answered
How to sub in multiple vectors into a structure
vars = num2cell([o2; o5; o6; x5; dx; Fs]); Sol_struct.Ax = double(subs(Sol_struct.Ax, vars, Cell_matrix)); Cell_matrix would h...

2 days ago | 1

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