# 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 T0099000; if you are waiting on a reply from me for an older issue, please send me a reminder.

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**Content Feed**

How do you define a structure array?

Possibly procPar already exists but is not a struct or table already. Possibly Dsifile exists but is not a struct or table.

11 hours ago | 0

Looping through 4 Images that have fixed names

IMList = {app.IM1, app.IM2, app.IM3, app.IM4}; nimg = length(IMList); for K = 1 : nimg IM = IMList{K}; app.ROI_C = ...

11 hours ago | 0

Result for solve( ) with minimized number of parameters

No. You asked to solve in terms of u and x2, so the results always have to have u and x2 expressed in terms of constants or inde...

13 hours ago | 0

I get wrong value

omega_p-(Nr/Np)*omega_r== omega_c *( 1- (Nr/Np)); omega_s-omega_c * ( 1+ (Np/Ns))==-(Np/Ns)*omega_p ; Those statements con...

15 hours ago | 0

Issue accessing external functions with matlab on linux

Look at all those mex files. They are compiled implementation for windows 32, windows 64, and mac, but none for Linux. A lot of ...

15 hours ago | 1

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Is this combination of parfor and global variables prone to errors?

That should work, as long as the principal function sets the global variables on every call, or at least tests whether they alre...

21 hours ago | 1

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The beginning of my graph is getting the wrong values. values for x=20,25 and 30 are correct. can someone help?

x=0:5:30; y = (110) .* x ./ (5+x) .* exp((-0.8*x)/8); plot(x,y)

1 day ago | 0

use cell items in the conv

conv() will never be able to process cell arrays . You need to use ab = conv(a{u,1}, b{v,})

1 day ago | 0

How would I put this into a graph?

syms x y = randi(256) ./ (x ./ randi(10) + x) .* exp(-rand() .* x ./ randi(10)) fplot(y)

1 day ago | 0

Array indices must be positive integers or logical values.

t = linspace(0,2,1000); t is a (real) vector of length 1000 if t(1i) <= 1 That asks to index the vector t at location 1i...

1 day ago | 1

How to find the common dates between two different variables that are not the same size or format?

dtdt = datetime(dt, 'ConvertFrom', 'datenum', 'Format', 'dd-MMM-yyyy HH'); dtday = dateshift(dtdt, 'start', 'day'); %change...

1 day ago | 0

How to insert variables (string) in MATLAB function

rotmatx('y', 'p') rotmatx('z', pi/6) function R=rotmatx(axis,q) Q = sym(q); if axis=='x' R=[1 0 0;0 c...

1 day ago | 1

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for文とif 文

rng(1,'philox') X = randi([0 1], 3, 3, 100); a = tril(ones(3), -1) == 1; a = repmat(a, 1, 1, 100); X(a) = 0; X = X + permut...

2 days ago | 0

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How to avoid duplication of random numbers?

node_sequence = randperm(n, t-reply_timer); Now use the elements of node_sequence, in that order. You will quickly get an erro...

2 days ago | 0

Vpa Solve solving for B

M1 = 3; P1 = 1; theta2 = 15; thetha3 = 20; gamma = 1.4; syms beta tantheta = tand(theta2); x = 2*cotd(beta)*((M1^2*...

2 days ago | 0

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Can I use the MEX function and compiler with a student license?

mex() is part of basic MATLAB. It relies upon third-party compilers to generate binary code from C or C++ (or fortran) code that...

2 days ago | 0

Extract first non-NaN of each row without loop

A=[NaN,444,NaN,NaN,41; NaN,NaN,NaN,222,NaN; NaN,NaN,554,554,NaN; 125,747,21,NaN,4; NaN,NaN,NaN,43,NaN; ...

2 days ago | 0

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Plot not updating even after changing plot data

You are not plotting into the axes you think you are plotting into. https://www.mathworks.com/matlabcentral/answers/22208-show-...

2 days ago | 0

having trouble writing a code that produce this graph.

Hint: plot([-3 0 0], [0 0 -4]); xlim([-5 5]); ylim([-5 5])

2 days ago | 0

Displaying values of x, ode45 and real y in a fprintf command

Yes and no. Yes, you can include an fprintf() statement inside your ode function, and that fprintf() statement will display wha...

3 days ago | 0

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Find Command not working.

T = [NaN 0.1:0.1:0.9] a = 0.3; Visually, it looks like 0.3 is in T find(T == a) But find() says it is not there. Is it the...

3 days ago | 0

Sum of previous 5 numbers

A=[2 3 4 5 6 7 8 9 10 8 5]; B=[0 2 5 9 14 20 25 30 35 40 42 ]; N = 5; C = movsum([0 A(1:end-1)], [(N-1) 0]) isequal(C, B)

3 days ago | 0

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lla2ecef is not supported for code generation

https://www.mathworks.com/matlabcentral/mlc-downloads/downloads/submissions/7942/versions/1/previews/lla2ecef.m/index.html

3 days ago | 0

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how to make Cubesat fixed

You need a geosynchronous orbit, which is about 42164 km from the centre of the Earth. (Careful, orbits are also often specified...

3 days ago | 0

How can we know whether the current execution of command is conducting inside a function or not?

The functions nargin and nargout will error if executed at the base. So you can use try/catch inbase = false; try; nargin; cat...

4 days ago | 0

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My codes won't show in the plots.

for i =0:n; vo1 = readVoltage(A,'A0'); vo2 = readVoltage(A,'A1'); vo3 = readVoltage(A,'A2'); end Every time thr...

4 days ago | 0

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If I upload a MATLAB video to YouTube, I wonder if there are any legal issues.

Academic licenses may be used for the education purposes and internal purposes of the university, including non-commercial resea...

4 days ago | 0

Avoid overlapping of node labels in graph

Not using the plot() call. Changing the layout might help https://www.mathworks.com/help/matlab/ref/matlab.graphics.chart.primi...

4 days ago | 0

Genetic Algorithm Plotter does not display

opts=optimoptions('ga', 'FunctionTolerance', 1E-9, 'MaxGenerations', 5000000, 'MaxStallGenerations', 500000, 'HybridFcn', 'patte...

4 days ago | 0

Defining a function for a vector of values, while keeping two variables unknown

So I must achieve the function, EV(x,i), and then replace by the values of x and i If you must achieve the function first, and ...

4 days ago | 0

| accepted