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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
i have excel sheet 31 coulmn,, the first coulmn is time and in the other coulmns the signals names , what i need from the code is that at spefic time to tell me for examplk
Given a particular scalar row index (calculated from the time, perhaps): VarNames = YourTable.Properties.VariableNames; Valu...

5 hours ago | 0

| accepted

Answered
How to delete all Files not listed in "FileName" variable?
Use arrayfun(@delete, F)

5 hours ago | 0

| accepted

Answered
error because "pkg load symbolic"
That code is not MATLAB code; it is Octave code. For MATLAB comment out pkg load symbolic Note: Fww0=round(eval(Fw(w0))*1000)...

6 hours ago | 0

Answered
Issue using fmincon, using code not written by my group and updating it to work now
For debugging, call aerospike_main(x0, at, pinf, p0, gamma, numsteps) and examine the results. See if there is an error messag...

6 hours ago | 0

Answered
How to store intermediate values of solution in ode45
Doing that would be a mistake. Runge-Kutta methods such as ode45 always have a "current" state, and a current step size. They e...

7 hours ago | 0

Answered
Printing special characters in an axis label
Temp = -19.6 ylabel(sprintf('T at %.0f \\circF',Temp), 'Interpreter', 'tex')

7 hours ago | 0

Answered
How to set the result output format of the matlab software to be the same as that in the webpage?
You cannot do that. The format you see on web pages is only available if you use LiveScript, and is not available from the comm...

7 hours ago | 0

Answered
drawing a point in the graph
x = 0:0.5:10; t = (x/2).^2; abs(x-2*sqrt(t)) %cross-check weether x == 2*sqrt(t) plot(x, t, '*-')

8 hours ago | 0

Answered
Location of a value in a matrix
x = 0:0.5:20 find(x == 9.5) However... x = 0:0.1:20 find(x == 0.3) [found, idx] = ismembertol(0.3, x) It is typically (muc...

8 hours ago | 1

Answered
two while loops running at same time
In order to run two loops independently of each other, you will need to use one of: parfeval and backgroundPool -- part of basi...

10 hours ago | 0

Answered
How to increase line width of a comet plot
Unfortunately there is no provision for that. The code creates graphics objects with Tag 'head' (line object), 'tail' (animated...

10 hours ago | 0

Answered
Clear Plot without clearing UI elements
UI controls are never the children of axes, so deleting or clearing the axes will not affect ui controls. If you want to remove...

11 hours ago | 0

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Answered
Combining different font styles while using latex interpretor
Unfortunately, MATLAB does not permit including the amsfont package, or any other font package. The only font control you get wi...

12 hours ago | 0

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Answered
Find minimum value of a function with 4 parameters
only change is your lower bound and upper bound need to be length 4

19 hours ago | 0

Answered
Hi, Im trying to generate the C code for my matlab code using Matlab Coder. I got a lot of errors and one of them is Function 'imshow' not supported for code generation.
You do not fix it. Or you fix it by telling matlab Coder that imshow is an external function and then provide your own imshow th...

1 day ago | 0

Answered
Using subs on list of symbols
name = sprintf('means%d_',m); sym_means(:,m) = sym(name,[1,p]); When you sym() a name and give a size, you generate a ...

1 day ago | 0

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Answered
how does matrix division work in matlab?
Mathematically (but not in practice) if you have a column vector b and a square array A, then A*x = b is the same as saying that...

1 day ago | 0

Answered
Saved MAT file in the computer is greater than raw .mf4 file
Check whether you have set your preferences to save to v7.3 mat files. v7.3 can be efficient for plain numeric arrays but they h...

1 day ago | 0

Answered
How can I add a custom compact display in a way that does not produce errors in MATLAB versions prior to 2021b?
Have a class that has a property. In the code that initializes the property, use verlessthan to test whether you are running ...

2 days ago | 0

Answered
Is there a MATLAB function similar to 'Spectrum0.ar()' from R?
https://www.mathworks.com/help/signal/ref/pyulear.html maybe ? There is also https://www.mathworks.com/help/signal/ref/periodog...

2 days ago | 0

Answered
/tmp/.e6fa-d450-cf2c-87f9.tmp Invalid cross-device link
See https://www.mathworks.com/matlabcentral/answers/1798895-invalid-cross-device-link-18-when-saving-a-file-on-arch-linux#commen...

2 days ago | 0

Answered
Populate a column vector with values from another column vector
A = randi(9, 1, 50); zeros_at = [0,1,2,5,7,8,11]; B = zeros(1, numel(A) + length(zeros_at)); mask = ismember((0 : length(B)-1...

2 days ago | 1

| accepted

Answered
I could not find Longitudinal driver block in trial version R2022b. How to download
That driver is part of the Powertrain Blockset product; https://www.mathworks.com/help/autoblks/index.html I do not know if th...

2 days ago | 0

Answered
How to split WAV files which have grown larger than file size limit
You could try the code at https://gist.github.com/phenyque/0137d70cad0ccababfd9b7629ae1b5aa However, depending on how the data...

2 days ago | 0

Answered
Indez in position 1 exceeds array bounds. Index must not exceed 2.
R=[-2436.45; -2436.45; 6891.0379]; V=[5.088611; -5.088611; 0]; x0=[R;V]; x0=x0*1000; dt=1; tVector=linspace(0,86400,2); xf...

2 days ago | 1

| accepted

Answered
too many output arguments, ploting loop function
We do not have your functions. What we do have is your line of code [a,b]=H2MSA_conversion(lifetime(j),efficiency(i), m...

2 days ago | 0

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Answered
Vertcat, I think I need to have consistent rows and columns, erroring out on B matrix creation. Can anyone show me how to make this correct?
clear all a=3; b=13; c=0; rG2a=a/2; rG3a=b/2; omega2=2000*2*pi/60; %rad/s alpha2=0; W2=1; W3=.5; W4=.2; I2=.002; I3=...

2 days ago | 0

Answered
Triple integral with absolute value limits
lambda1=25/(1000)^2; lambda2=100/(1000)^2 fun =integral3(@(l0,l2,l1) (l1.^-3).*exp(-pi*(lambda2.*l2.^(2)+lambda1.*l0.^(2)))./(...

2 days ago | 0

Answered
How to load multiple txt files with many rows and 4 columns and get mean of 3rd and 4th columns
projectdir = '.'; %absolute path would be even better dinfo = dir( fullfile(projectdir, '*.txt')); filenames = fullfile({din...

2 days ago | 1

| accepted

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