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Walter Roberson


Last seen: Today |  Active since 2011

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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 reduce the usage of "broadcast variables" when using parfor
"Is there a way to avoid this "unnecessary communication overhead", so that this parfor loop can run faster please?" No. You ...

alrededor de 4 horas ago | 0

Answered
Question about the fminsearch Algorithm
"So, first I wanted to know if my thoughts are correct?" Yes. "Intuitively I would say that it would be more effective if ...

alrededor de 4 horas ago | 0

Answered
Writing to .mat simultaneously with parfor loop
This is a valid concern. save() does not promise to be thread-safe If I recall correctly, a few weeks ago there was a post fr...

alrededor de 4 horas ago | 1

Answered
I'm trying to save a sequence of images generated in MATLAB individually
"Firstly, is there a different way to save them individually, despite the fact they're in a cell?" No. Some of the image writ...

alrededor de 4 horas ago | 0

Answered
How to increase the resolution of a list of images
You have a series of images that all happen to be bright in certain areas. Because they are all bright there, the variance betwe...

alrededor de 5 horas ago | 0

Answered
Can I share my standalone desktop application to be used freely by end product users?
No, with the Academic license, you can share the executable "for internal purposes" within your organization, or with your resea...

alrededor de 6 horas ago | 0

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 17 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 18 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 18 horas ago | 0

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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 19 horas ago | 0

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

alrededor de 19 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...

1 día ago | 0

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

1 día 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 = ...

1 día 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 ...

1 día ago | 0

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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)...

1 día ago | 0

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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...

1 día 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...

1 día 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 ...

1 día ago | 1

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

1 día 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

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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

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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...

2 días 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...

2 días 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 ...

2 días ago | 0

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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.

2 días ago | 0

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