# Walter Roberson

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.

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Error message Error using mupadengine/feval_internal More equations than variables is only supported for polynomial systems. Error in sym/vpasolve (line 172) sol = eng.fe

Your T10 is a 4 dimensional array so your P becomes 4 dimensional. In order to vpasolve an expression involving that array, you ...

ongeveer 2 uur ago | 0

| accepted

How to add trip_sum to table without error?

You have an existing trip_table variable that was built with a different number of variables. I suggest you build your table on...

ongeveer 15 uur ago | 0

How to quickly view the variables in the mat file? My computer is poor, so it is slow to open matlab😭

https://comp.soft-sys.matlab.narkive.com/hkUdFzb0/quickly-list-variables-in-a-mat-file shows some C code that when compiled with...

ongeveer 20 uur ago | 0

vpasolve unable to find solution of 6 simultaneous equations

You need to arrayfun or loop over elements of V_i as vpasolve and solve try to solve all of the passed equations simultaneously ...

1 dag ago | 0

I need help to solve this problem, I don't understand why it's not working

configure the arduino and servos *once* in Classroom_security_OpeningFcn not in every callback. Also use try/catch in ca...

1 dag ago | 0

help to find error in this?

https://www.mathworks.com/help/matlab/math/parameterizing-functions.html global is not recommended

1 dag ago | 0

Dimension 1 is fixed on the left-hand side but varies on the right ([512 x 512] ~= [:? x :?]).

in the interface block you specified the signal size as 512 by 512. It is not marked as variable sized, and the 512 512 will *no...

1 dag ago | 0

conversation of (129x7 complex double) to an Image

you could use the tiff gateway and write the imaginary component as unassociated alpha. There is an example at https://www.ma...

1 dag ago | 0

I can not use log function in matlab

Your MATLAB installation is corrupted. You need to reinstall it.

1 dag ago | 1

Define a family of functions

If you *could* define a "family of functions" in MATLAB, what properties would you want such a thing to have? If there were clas...

1 dag ago | 0

Error using feval Function to evaluate must be represented as a string scalar, character vector, or function_handle object.

syms t f(t)=[-cos(t), -sin(t), 2*cos(t)^3 - 7*cos(t)*sin(t)^2] Then output = feval(f,3.14) %must "use" the output or f(3....

1 dag ago | 0

How to solve Multivariate equations

syms s phi theta; First you create symbolic variables. The MATLAB level variables s phi and theta will be assig...

1 dag ago | 0

The embedded function "allSimplePaths" in the allpaths.m

allSimplePaths is a built-in method % matlab.internal.graph.MLDigraph method It is an undocumented internal function.

2 dagen ago | 0

How to have legend coloured according to data

I suggest you consider using gscatter Otherwise, you have two possibilities: use one scatter() call for each different group, ...

2 dagen ago | 0

| accepted

Is it possible to select two points automatically from an image?

Information can only be automatically extracted if there is a programmable rule that describes how to distinguish the informatio...

2 dagen ago | 0

How do you ask the user to load a path from the .xlsx file, then store it in variables with some concerns when reading the .xlsx file using app designer?

I opened in the file in Excel. In the first sheet in the file, "AC No ESS", there are only 5 columns, and readtable() finds them...

2 dagen ago | 0

Why is my FFT diagram has a slope approaching to zero?

Fs=1000; T=1/Fs; t1 = readtable('t.xlsx'); L = width(t1); t = t1{1,:}; S = t1{2,:}; plot(t,S) f=Fs*(0:(L/2))/L; Y ...

2 dagen ago | 0

Is it possible to call parfeval from within a parfor loop

No, that is not possible. See https://www.mathworks.com/matlabcentral/answers/1904941-dual-parfor-from-different-scripts#answer...

3 dagen ago | 0

How can I make my 'x' matrix in scatterplot in 2 different colors??

scatter() can take information about color in the 4th parameter. The color information can be set per-point. xdata = repmat(Tem...

3 dagen ago | 1

How can I make my 'x' matrix in scatterplot in 2 different colors??

A different approach would be to use gscatter xdata = repmat(Temp, 5, 1); ydata = [Bin1; Bin2; Bin3; Bin4; Bin5]; g = 2 * one...

3 dagen ago | 1

Save each loop from getfield command

It is not clear to me why you are using that getfield instead of ffextract = fftrials{1,1}(1,n).df; You have for n=1:size(fft...

3 dagen ago | 0

combine the string and number

Are you referring to combine for augmented image data store? If so then each element you combine, such as bldsTrainT, must be a...

3 dagen ago | 1

| accepted

Efficient code for multiple string replace

If you are going to write something like that, then you should write it in the clearest way you can come up with, because you ar...

3 dagen ago | 0

How to encrypt compilation files for standalone?

https://www.mathworks.com/help/matlab/matlab_prog/protect-your-source-code.html Starting in R2021b, you can obscure the names ...

3 dagen ago | 1

is that really necessary to measure and put the weakness of the thesis if it is not scope of the work?

This is not a MATLAB question, so it isn't really appropriate here. In my opinion, the answer is Yes, you need to discuss perfo...

3 dagen ago | 0

| accepted

Is my mathematical problem to hard for single GPU computation?

You have one GPU. When you try to use that one GPU from multiple workers, then each time a different worker gets control, it has...

3 dagen ago | 0

| accepted

Is it possible to implement a GUI in a Matlab script?

see "App Designer" for a more modern interface, or see "GUIDE" for an older interface (that has much better performance)

3 dagen ago | 0

This can be solved

for x=value if x is in a certain range y = appropriate calculation elseif x is in a different range ...

3 dagen ago | 0

Isn't it dangerous to allow Comma-Separated-List functionality in indexed assignments?

Consider x = rand(1,10); y = power(max(x),2) %also known as y = max(x).^2 How many outputs does max(x) potentially have? Tw...

4 dagen ago | 0

solving a matrix equation

You have 13 equations that you are trying to solve for 12 variables. tic syms thdd1 thdd2 thdd3 q1 q2 q3 xdd ydd zdd thddo1 th...

4 dagen ago | 0