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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.

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Answered
Assignment between unlike types is not allowed for two function in a loop
It looks like your function is returning struct variables. When you have code of the form struct1(index) = struct2 wh...

alrededor de 2 horas ago | 0

Answered
Error while evaluating UIControl Callback.
You need to contact your company to have them authorize you to use that toolbox.

alrededor de 8 horas ago | 0

Answered
Using linspace outside of field data areas?
Use scatteredInterpolant() with the Extrapolation Method set to 'none'

alrededor de 9 horas ago | 0

| accepted

Answered
How to remove an unwanted horizontal line at a specific domain on the x-axis?
Your size variable is not in sorted order, but you are using it as the independent variable for the plot, so MATLAB has to draw ...

alrededor de 9 horas ago | 0

| accepted

Answered
Constraints used but not applied (beginner)
E_pv = npv * Apv * Iir(1 - 0:005(Ta((t) - 25)); %all the varibles have scalar values That is invalid syntax. 0:005(Ta((t) - 25)...

alrededor de 9 horas ago | 0

Answered
Reistall matlab with the same license
Yes. Unless the details of the license changed in R2021a (I have not checked the wording for that release), then students are n...

alrededor de 10 horas ago | 0

Answered
error Unbalanced or unexpected parenthesis or bracket
c1 = 1000*Q1*e./(4*pi*(xx1>0).*xx1*sqrt(Dy*Dz)*v).*exp(-v*yy1.*yy1./(4*Dy*(xx1>0.*(exp(-v*(z-H1)*e./(4*Dz*(xx1>0).*xx1)).*(exp(-...

alrededor de 10 horas ago | 0

Answered
Auction Algorithm is not converging due to round off error in dell 7820
min() never does rounding. min() of a single parameter uses bit-for-bit comparisons (since the entire array is always the same d...

alrededor de 10 horas ago | 1

Answered
Can I install a unit of MATLAB for PC to the server?
Mathworks has available several related licenses for that purpose: Networked Named User: the license is made available through ...

alrededor de 11 horas ago | 0

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Answered
Why is x(:) so much slower than reshape(x,N,1) with complex arrays?
Nx = 256; Ny = 256; Nz = 128; N = Nx*Ny*Nz; A0 = rand(Nx, Ny, Nz); timeit(@() use_colon(A0, N), 0) timeit(@() use_resh...

alrededor de 12 horas ago | 0

Answered
openmp options changed by MATLAB?
Roberto, did you deliberately configure your cluster profile (which might be profile named 'default') to provide more than one t...

alrededor de 13 horas ago | 0

Answered
What functions should be moved to basic MATLAB?
wrapToPi() has obvious uses outside the Mapping Toolbox https://www.mathworks.com/help/map/ref/wraptopi.html

alrededor de 18 horas ago | 0

Answered
How to plot curve instead of straight line in MATLAB?
The MATLAB routines for plotting curves instead of straight lines are: viscircles() (Image Processing Toolbox) rectangle() (ba...

alrededor de 19 horas ago | 0

Answered
Program architecture for handling large .csv files
In some cases, depending on the format of the file, you have some options of how to proceed: readtable() and readmatrix() and r...

alrededor de 20 horas ago | 0

Answered
How can I create a mat file which changes the values of a column in excel table into the mat file's column headers?
findgroups() on the IDs. splitapply() to split into groups -- you can use for example splitapply(@(x) {x}, Variables, Group) O...

alrededor de 20 horas ago | 0

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Answered
Matlab r2020a becomes extremely laggy after several hours
If you are using any window management program such as Magnet, then disable that or configure MATLAB to be excluded. If you h...

1 día ago | 3

| accepted

Answered
why do I get a strange result with griddata cubic?
This is expected behavior when there are sharp edges, especially with a surrounding flat area. B-- | -A- Es...

1 día ago | 0

Answered
How to create a structure array?
findgroups(), and use the group numbers to splitapply() where the work function is @(x){x} . The results should be a cell array....

1 día ago | 0

Answered
append rows of a table
The general solution is to vertcat or [;] a cell array that has the same number of columns that as the table has variables. This...

1 día ago | 0

Answered
gui size problem on another computer
https://www.mathworks.com/help/matlab/ref/matlab.ui.control.uicontrol-properties.html#d123e1411378 The default Units for uicon...

2 días ago | 0

Answered
How to change the default range of hyperparameters in fitcecoc function?
In the section https://www.mathworks.com/help/stats/fitcecoc.html#d123e297982 Set nondefault parameters by passing a vector of...

2 días ago | 0

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Answered
how to calculate the gamma function when the variables are the complex numbers?
The Symbolic Toolbox can calculate it. format long g a = sym(complex(randn, randn)) g1 = gamma(1/4 + 1/2*1i*a) double(g1)

3 días ago | 0

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Answered
how to use setvartype on a table that is already existing
Can someone tell me how to set all the variable types to one uniform type using setvartype function? That is not possible. setv...

3 días ago | 0

Answered
I want to shorten a string.
If it is a string() object then see extractAfter()

3 días ago | 1

| accepted

Answered
Which Processor and how much RAM is required?
https://www.notebookcheck.net/AMD-Ryzen-7-5700U-Processor-Benchmarks-and-Specs.510416.0.html That Ryzen does support AVX2. If...

3 días ago | 0

Answered
Support vector machine for multi-class
https://www.mathworks.com/help/stats/classificationecoc.html#bue3o6e-12 So use one row for each sample, and the columns are th...

3 días ago | 0

| accepted

Answered
how to create a variable without assigning a value to it and also the variables shouldnt be symbolic variables
syms e d m = [27.5084 -10.7668 -9.7727;-20.6533 15.8060 14.8502]; k1 = m * e; %not used k2c = arrayfun(@(V) tf(V,[1 ...

4 días ago | 0

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Answered
storing loop values in a matrix
N = 10; iters = 5; column = randi(9,N,1) results_of_loop = zeros(N, iters); for K = 1 : iters results_of_loop(:,K) = co...

4 días ago | 0

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Answered
i need help writing code in matlab that will plot data of 4 different variables onto one graph
format long g data = { 'earth', 14.3145, 2756.22, 228.060 'venus', 15.0717, 3580.80, 224.65 'mars', 13.7819, 27...

4 días ago | 0

Answered
Efficient way to implement this UDP protocol for loopback IP
udp does not synchronize: is is completely happy to send of 1000 packets from a source in the time before the first of them is p...

5 días ago | 0

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