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Walter Roberson


Last seen: Today Active 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. I am currently caught up to T0099119; if you are waiting on a reply from me for an older issue, please send me a reminder.

Programming Languages:
C, MATLAB, Shell, Perl, Fortran
Spoken Languages:
English

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Answered
how to load multiple files from directory into an array using matlab?
dinfo = dir('*.mat'); filenames = {dinfo.name}; for K = 1 : length(filenames) temp = load(filenames{i}); FN = fieldn...

alrededor de 5 horas ago | 0

Answered
HOW TO XOR NEGETIVE DECIMAL NUMBER?
for i=1:16 S = dec2bin(typecast(double(smod(i)), 'uint8'), 8) - '0'); F = dec2bin(typecast(double(finalkey(i)), 'uint8...

alrededor de 5 horas ago | 0

Answered
Unable to find explicit solution
That equation is much too complex to hope for a closed form solution. You will not be able to find a symbolic solution. For a...

alrededor de 6 horas ago | 0

Answered
Please How I can use meshgrid with x and y are the elements of the matrix A and plot a figure like in the picture
This does not look like a contour plot at first, but notice the upper right corner. syms P Q D = det([P, 2; 0, Q]); x = linsp...

alrededor de 6 horas ago | 0

| accepted

Answered
why am I getting this error ? Any help please
filename = file_list{i}; data_in = readtable( fullfile(path_n, filename) );

alrededor de 7 horas ago | 1

Answered
MATLAB doesn´t open after activation
See https://www.mathworks.com/matlabcentral/answers/106141-why-am-i-continuously-prompted-to-activate-when-i-try-to-launch-matla...

alrededor de 19 horas ago | 0

Answered
modifying an identity matrix
I = eye(7) r = size(I,1); newI = diag([ones(1,r-2), 0],-1) + I

alrededor de 19 horas ago | 0

| accepted

Answered
Help with neighbor function - inconsistent node connections
MaxNeigh = 3; neigh = zeros(MaxNeigh,1); coder.varsize('neigh', [MaxNeigh 1], [1 0]); %second dimension is fixed neigh = ...

alrededor de 19 horas ago | 0

Answered
How to convert an optimization variable to symbolic variable?
It does not appear to be documented, but use optimexpr2fcn() on the optimization expression, to get back a function handle to a ...

alrededor de 19 horas ago | 0

| accepted

Answered
Data dimensions must agree. Using surf
[pA, T] = meshgrid(7600000:100000:20000000, 313:1:373); mu = ((((-0.1146067)+(0.000000697838).*(pA/100000)+(0.0000000003976765)...

alrededor de 20 horas ago | 0

| accepted

Answered
Compiling CUDA files with mexcuda in matlab2021b report error
Look at https://www.mathworks.com/content/dam/mathworks/mathworks-dot-com/support/sysreq/files/system-requirements-release-2021...

alrededor de 20 horas ago | 0

Answered
How to use lsqnonlin command for solving a cost function minimization problem which consists of optimization variable?
C = [0 0 0 1 0 1 0 0]; D = [0;0]; x = [zeros(4,1)]; u = optimvar('U',2); f=0; % for loop here to create an object...

alrededor de 20 horas ago | 0

Answered
How would I detect gray/white pixels in a picture?
Convert for HSV, check for "high" V (near 1) and "small" (near 0) S. You will need to decide on the exact boundaries, depending ...

alrededor de 20 horas ago | 1

| accepted

Answered
Use workspace variable in equation solver
syms x y eqn = x + y == 25 y = 5 subs(eqn) y = 9 subs(eqn)

alrededor de 21 horas ago | 0

Answered
What does the warning "Integrand function outputs did not match to the required tolerance" mean?
Yes, it does mean the value is inaccurate. It means that the value is probably meaningless. You probably used / or * instead of...

1 día ago | 0

Answered
Send data from an array to NumericEditFields
app.Simul = sim(app.Calling.net_SOLD,app.D2); app.EditField_1.Value = app.Simul(1); app.EditField_2.Va...

1 día ago | 1

Answered
Can one of MATLAB's optimization algorithms (e.g. particle swarm optimization) take the place of this brute force parameter sweep iteration?
In theory, NO, none of those functions can take the place of a parameter sweep for a generalized calculation. There are calcula...

1 día ago | 0

Answered
Difficulties in Assembling an array from NumericEditFields in app designer
app.D1 = [app.Is.Value; app.Us.Value; app.Vs.Value; app.Es.Value]; Or... you could leave app.D1 as it is, and at the time you n...

1 día ago | 1

| accepted

Answered
Convert some Table Variables from Cell to Double
for i = 1 : length(holdNames) thisname = holdNames{i}; T.(thisname) = str2double(T.(thisname)); end

1 día ago | 0

| accepted

Answered
Add dates in x-axis of every graph
datetick() is not "sticky": it does a one-time conversion of the xlim range into formatted ticks, or (depending on the option) t...

1 día ago | 0

Answered
how to find specific string out of a list in an excel
data = readtable('FileNameGoesHere'); mask = data{:,ColumnNumberGoesHere} == 9; subset = data(mask,:); writetable(subset, 'sa...

1 día ago | 1

Answered
Two variables concatenation to one in Simulink
How do you want distinguish these cases: A = 1234 B = 567 A = 123 B = 4567 What do you want to do if the values are negative...

1 día ago | 0

Answered
How to compile MEX binary that only works on 64 bit Linux to use it on macOS?
It is not necessary to cross-compile; the GIT repository includes the .cpp source code (and the .c sources needed for different ...

1 día ago | 0

| accepted

Answered
Can I run MATLAB (R2017 or newer) on a Lenovo Chromebook with an AMD A4 processor?
No, the only supported operating systems are Windows, Linux, and MacOS. ChromeOS is not supported.

1 día ago | 0

Answered
how can I plot this figures
https://www.mathworks.com/help/matlab/ref/histcounts2.html can be used to calculate the counts for density plot purposes. images...

2 días ago | 0

Answered
How to concatenate/combine a list of images in one mat.file (convert picture 1 into picture 2)
What you are asking for is possible but not recommended. You are asking to open the variable browser on each field of the struct...

2 días ago | 0

Answered
Fmincon Error Message please help!
In order to get that error at that line of code, your function Obj_Complex had to have generated an error message when evaluated...

2 días ago | 0

Answered
OPEN(OPEN_COUNT,:)=insert_open(xNode,yNode,path_cost,goal_distance); how to solve this error please help fast
https://www.mathworks.com/matlabcentral/fileexchange/26248-a-a-star-search-for-path-planning-tutorial has the source code

2 días ago | 0

Answered
How can i reshape a matrix
reshape(permute(M1, [1 3 2]),[],size(M1,2))

3 días ago | 0

| accepted

Answered
How to show the cross cursor (instead of arrow) when clicking on the UIAxes in the App designer? How to save several coordinates when clicking for times via upButtonfunc?
https://www.mathworks.com/matlabcentral/answers/496366-how-do-i-change-the-pointer-property-on-a-ui-figure for information on...

3 días ago | 0

| accepted

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