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Walter Roberson


44,628 total contributions 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
Chaotic bit stream cipher
Logicists maps can be used for this purposes, as they only need to know the current state. "cat map" on the other hand requires...

2 hours ago | 0

Answered
Which interpolation method is best?
Use https://www.mathworks.com/help/matlab/ref/fillmissing.html#bva1z1c-method fillmissing() -- it supports all of the methods yo...

2 hours ago | 0

Answered
How to read and process a text file?
S = fileread('sample.txt'); S = regexprep(S, {'^\$.*?\n', '\r'}, {'', ''}, 'lineanchors'); all_ids = string(regexp(S, '^\S*', ...

2 hours ago | 0

Answered
Every time during the starting of MATLAB these two warnings pop up?
https://www.mathworks.com/matlabcentral/answers/472134-gtk-message-10-32-31-466-failed-to-load-module-canberra-gtk-module

14 hours ago | 0

Answered
jetson function package not found
https://www.mathworks.com/help/supportpkg/nvidia/ref/jetson.jetson.html GPU Coder Support For Nvidia GPU is the required supp...

14 hours ago | 0

Answered
Multiple print outside of loop
Your c is a vector because of the rand(100, 1) None of the code is expecting a vector for c. Note that if you are trying t...

15 hours ago | 0

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Answered
my code doesnt show a graph even if i use the plot command
sinoaz=-23.45*(pi/180)*cos(((2*pi)/365)*(10+n)); Should use n_days instead of n A=asind(sinAz); Should be A(...

15 hours ago | 0

Answered
Image Write in Excel
https://answers.microsoft.com/en-us/msoffice/forum/all/what-is-the-maximum-number-of-columns-in-a/5a053135-4865-e011-8dfc-68b599...

16 hours ago | 0

Answered
coswm should have a 1x365 dimension, but its dimension is 1x1, what am i doing wrong?
The / operator is Matrix Right Divide, which is least squares fitting effectively. If you did not intend to do fitting at that p...

18 hours ago | 0

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Answered
How can I know if my laptop is plugged into AC power via Matlab?
<https://stackoverflow.com/questions/21249419/how-do-i-programatically-detect-if-my-laptop-is-plugged-in-or-not-osx> You can ...

19 hours ago | 0

Answered
I have MatlabR2019b and I am trying to do a simple plot. I am not able to plot anything unless I use scatter(x,y) or area(x,y). How could I get plot(x,y) to work? I am using a Mac.
You need to rename plot.m in the untitled folder directory as it is overriding the Mathworks plot call

1 day ago | 1

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Answered
Error Message Using ODE45
The part starting from [t,y] = ode45(@vdp1,[0 20],[2; 0]); plot(t,y(:,1),'-o',t,y(:,2),'-o') Should be in a differen...

2 days ago | 0

Answered
fsolve to solve 5th order polynomial
You have an equation of the form A=B. Subtract B from both sides giving an equation of the form (A) - (B) = 0. Now you can fsolv...

2 days ago | 1

Answered
How to convert a grey-scale image into a reverse binary image
Rbin = YourImage <= 42;

2 days ago | 0

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Answered
Using timer, How can I cleanly exit a function execution, when the timer fires in MATLAB?
There are only four ways in MATLAB to force a function to stop executing without its cooperation: quit MATLAB force an out-of-...

2 days ago | 0

Answered
Getting a empty sym 0x1 error when I run this code
[dP,dVg,dVf,dTf,dTg] = solve([eq1,eq2,eq3,eq4,eq5],[dP,dVg,dVf,dTf,dTg])

2 days ago | 0

Answered
Treating input arguments (not paying attention to order of number)
Use name/value pairs, unless there is something inside of the structs that identifies which kind of object it is for, or some ot...

2 days ago | 0

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Answered
Problem in text to plot ....
for i = 1:cycles i starts at 1 normal = -[Mf{i}(round(cutoff*length(Mf{i-1})):round((1-cutoff)*length(Mf{i-1})),3); Mf...

2 days ago | 0

| accepted

Answered
Matrix Dimensions Must agree
t=(0:tsd:4); t is a vector for j=1:length(t) taking length(t) again implies t is a vector. S(i,j) = exp...

3 days ago | 0

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Answered
Remove variables not shared by 4 tables
Create a cell array of the tables. For the moment I will call this tab_cell . Then shared_vars = tab_cell{1}.Properties.Variabl...

3 days ago | 0

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Answered
trasfer function to work space
You appear to have a simulink model named stepinfo somewhere on your path that is interfering with calling the Control Systems T...

3 days ago | 0

Answered
Integer check with a symbolic variable
if mod(p,1) == 0

3 days ago | 1

| accepted

Answered
What is the difference between structure and table?
table has a nicer output presentation, and should be more efficient in memory. It also has some useful operations especially whe...

3 days ago | 0

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Answered
year command does not work properly
It looks to me as if you are trying to read an excel numeric date. Excel uses Jan 1 1990 as its time base. If you have an exc...

3 days ago | 0

Answered
Trouble with DICOM values
You should be using the dicom RescaleSlope and RescaleIntercept. Convert the data to double, multiply by the slope, add the inte...

4 days ago | 0

Answered
Calling PSCAD to Matlab
https://hvdc.ca/pscad/automationlibrary You can have MATLAB call Python to use the pscad automation libraries This tends t...

4 days ago | 0

Answered
how to fill color outside of a map plot in matlab like an example given below
poly2mask() and repmat() [1 1 3], and set those locations in the RGB array to the maximum for your color range (typically 255 fo...

4 days ago | 0

Answered
Attempting to Plot Multiple Answers from a Loop
You do not define a variable V in your code, but you use it in the line xn=(V*T(i))+xn and you attempt to plot it several time...

4 days ago | 0

Answered
How to interface pscad with matlab?
http://www.ipstconf.org/papers/Proc_IPST1997/97IPST023.pdf https://www.researchgate.net/post/How_to_make_an_interface_between_M...

4 days ago | 0

Answered
Solving Numerical Differential Equation
Use v0 = 0; you tried to use an equation as an intial condition, but that can be done only for symbolic differential equations...

4 days ago | 0

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