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.

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C, MATLAB, Shell, Perl, Fortran
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English

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Answered
Which optimisation technique is the best and what is difference between metaheuristics and machine learning?
Suppose that you have a nonlinear function with multiple local minima, and you want to optimize it to find the global optimum. ...

environ 8 heures ago | 0

Answered
Constraint problem in Problem-based optimization live task
Notice that when you assign to problem.Constraints, you are asking to execute constraintFcn with those parameters, and the const...

environ 17 heures ago | 0

Answered
I have troubles in for loop with 2 variables.
"Therefore I think it should be 29 values but it has 30 values." But you said that when n = 30, x=1,2,3,...,30 -- which is 30 v...

environ 17 heures ago | 0

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Answered
How to read Excel files with unknown number of header rows?
I notice you are using R2019b. Starting with R2019a, you can use readcell . Then you would ask isnumeric(T{2,1}) to determine wh...

environ 17 heures ago | 0

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Answered
Newer Matlab versions assign sequence of plot handle double-values in a code-dependent way
I am not clear on why you would do this, instead of relying on the Children order of the axes? Are you re-ordering the Children ...

environ 20 heures ago | 0

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Answered
Is there a way to solve a system of nonlinear equations without the optimization toolbox (fsolve) or symbolic math toolbox (sym)?
Systems of equations can often be turned into a minimization. A = 4*kappa B = 2*alpha/(rho*c*A) D = -(r^2) % Equations eqn...

environ 20 heures ago | 0

Answered
How can I force a MATLAB plot with two y-axes to have 0 at the same height for both axes?
To have the plots have a common origin, you need to adjust the ylim() for one or both plots such that the first value for the se...

environ 20 heures ago | 0

Answered
is it possible for if/ else if statements to accept multiple string inputs?
if ismember(solid, {'yes', 'YES'}) but consider instead if strcmpi(solid, 'yes') the i in strcmpi means case-insensitive -- s...

environ 21 heures ago | 1

Answered
How to work variables outside function
People often ask to be able to get a copy outside the ode function of all of the values they computed inside the ode function. I...

environ 21 heures ago | 0

Answered
I have a .txt file that I need to turn into a vector
filename = 'Grades.txt'; %first create an example file example_data = "2 4 3 4"; writelines(example_data, filename); dbtyp...

environ 22 heures ago | 0

Answered
How can I add a letter to a column of strings. For example i want all names in the column one to change to this Name T.
%build an example table sourceletters = 'A':'P'; FirstColumn = string( sourceletters(randi(numel(sourceletters), 5, 7))); T =...

environ 22 heures ago | 1

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Answered
linear inequality constrains based on absolute values
x = linspace(-0.005, 0.005, 100); y = linspace(-0.005, 0.005, 101).'; M1 = x + y <= 0.1*abs(x); M2 = x + y >= -0.1*abs(x); [...

1 jour ago | 0

Answered
Neural network (NN)
net=newff(minmax(pn),[20,10,1],{'logsig','logsig','purelin'},'trainlm'); You are missing a parameter. The {'logsig'} and so on ...

1 jour ago | 0

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Answered
Im trying to use the integral function without any success...
In the symbolic toolbox, int() and solve() attempt to give indefinitely precise closed-form solutions. If int() is not able to f...

1 jour ago | 0

Answered
how can I plot the fourier series of this function by calculating the coeffcients and for different n?
an = zeros(1,n); i = 1 : n; mask = mod(4,i) == 3; an(1,mask) = -2./i(mask) * pi; mask = mod(4,i) == 1; an(1,mask) = +2./i...

1 jour ago | 0

Answered
How to open External Program by MATLAB?
system('"C:\Program Files\Bentley\Offshore\MAXSURF CONNECT Edition V23\MaxsurfModeler64.exe" &'); That is, if you put an & at t...

1 jour ago | 0

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Answered
trying to select multiple files to use in multiple s-parameter plots. I can see the file name when I manually use file1{1,2} but sparameters doesn't like it.
DefPath = 'C:\tmp\new anenna stuff\*.s4p'; [FileNames, PathName] = uigetfile(DefPath,'MultiSelect','on'); if...

1 jour ago | 0

Answered
Trying to integrate for drag
I suspect Integrate = u_wake .* (20-u_wake);

2 jours ago | 1

Answered
Find longest pattern of [1 0] in array.
The below code will find all of the subsets of maximum length (I do not assume that it will be unique) The union() are present ...

2 jours ago | 1

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Answered
How to code for summation?
Your sin(x) term is constant in n, so you can move it outside the summation. x = -pi:0.01:pi; sx = sin(x); factor = cumsum(2....

2 jours ago | 2

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Answered
MATLAB R2017a does not recognize a Visual Studio 2015 redistributable Compiler
https://www.mathworks.com/content/dam/mathworks/mathworks-dot-com/support/sysreq/files/SystemRequirements-Release2017a_Supported...

2 jours ago | 1

Answered
All Combination of Matrices from two single values
values = [1 2]; N = 3; outputs = reshape(values(dec2bin(0:2^(N^2)-1).' - '0' + 1), N, N, [])

2 jours ago | 0

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Answered
imread slower with huge tif files
Use the Tiff() class to work more directly with the tiff structure.

2 jours ago | 0

Answered
My shifting algorithm does not work at all cases. Could someone please give me feedback what's wrong at my code?
shift = shift_max * (shift/shift_max - round(shift/shift_max)); shift_max is not a power of 2. When you divide by something...

2 jours ago | 1

Answered
Solution of radical equation
We would not know if the code is correct as you did not show us the equations. We would, for example, not know whether the sin()...

2 jours ago | 1

Answered
Can you use the whos command to identify classes
numeric_classes = {'int8', 'uint8', 'int16', 'uint16', 'int32', 'uint32', 'int64', 'uint64', 'single', 'double'}; num_classes...

3 jours ago | 1

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Answered
How to create TCP IP Server in MATLAB R2020b without using tcpip command as it states it is not recommended.
tcpserver was introduced in R2021a . You appear to be asking what should have been used in R2020b -- the release before tcpserv...

3 jours ago | 0

Answered
plotting this program is causing a problem how to fix it?
[y(4),y(5),y(6)] = meshgrid(-4:0.25:4,-4:0.25:4,-4:0.25:4); You want y(4), y(5), y(6) to each represent a matrix of values. You...

3 jours ago | 0

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Answered
Fit a line and integration
You are asking for normalization. When you do that, coeffvalues are the coefficients for the normalized independent variable, no...

3 jours ago | 0

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Answered
How to assign column headings to .mat file?
It is not possible to add column headings to a mat file. However you can create a table() object and store it in the mat file...

3 jours ago | 0

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