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
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...

1 hour 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...

2 hours 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...

2 hours ago | 0

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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...

5 hours 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...

5 hours 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...

5 hours ago | 1

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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...

6 hours ago | 0

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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...

6 hours 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 =...

6 hours 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); [...

17 hours 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 ...

18 hours 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...

18 hours 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...

19 hours 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...

20 hours 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 day ago | 0

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

1 day 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 ...

1 day ago | 0

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....

1 day 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...

1 day 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, [])

1 day 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.

1 day ago | 0

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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...

1 day ago | 0

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()...

1 day ago | 0

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

2 days 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...

2 days 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...

2 days 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...

2 days 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...

2 days ago | 0

Answered
Splitting a String in a table once
I can tell from the way that the table displays that the entries are categorical() not character or string(). You would need to ...

3 days ago | 0

Answered
How can I limit the argument in coding the roots of a fraction?
root1 = solve(fp,x)

3 days ago | 0