# 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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C++, C, MATLAB, Shell, Perl, Fortran

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English

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**Content Feed**

Invalid use of operator error - GUI

You have % --- Executes on button press in Auto. function pushbutton_auto_Callback(hObject, eventdata, handles) % hObject ...

ungefär 2 timmar ago | 0

How to decide the number of workers by seeing computer specs like CPUS or Cores or threads?

By examination of your code, we can see that if any worker is scheduled for N iterations of the work, that it must take approxim...

ungefär 3 timmar ago | 0

Analyzing a Large Amount of Data in a CSV file

The line eval('cntry' string(j) '=A'); is the problem. You have a character vector, then a space, then a string scalar...

ungefär 4 timmar ago | 0

How to solve "File: first.m Line: 1 Column: 1 Invalid use of operator" error?

That is C code. It cannot be run directly from MATLAB. To call it from MATLAB, you would need to compile it, and then use loadl...

ungefär 4 timmar ago | 0

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'simulink' requires Simulink. Error

Your account is not licensed for Simulink. Note: the basic Student license (about $US50) does not include Simulink as part of t...

ungefär 15 timmar ago | 0

How can another person use my student licence?

You can only install MATLAB on a computer that you own or lease. You would only be permitted to install MATLAB on someone else's...

ungefär 15 timmar ago | 0

I would like to remove zeros from my matrix

a = [0 0 0; 0 0 0; 1 2 3; 4 5 6] b = rmmissing(standardizeMissing(a, 0))

ungefär 16 timmar ago | 0

How to read a txt file with comma, text and numbers in matlab, and export the data

http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F See also readtable()

ungefär 16 timmar ago | 0

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.

en dag 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 = ...

en dag 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...

en dag 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...

en dag 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 ...

en dag ago | 1

| accepted

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...

en dag 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)

2 dagar 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,})

2 dagar 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)

2 dagar 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...

2 dagar 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...

2 dagar 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...

2 dagar 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...

3 dagar 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...

3 dagar 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*...

3 dagar 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...

3 dagar 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; ...

3 dagar 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-...

3 dagar 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])

3 dagar 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...

4 dagar 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...

4 dagar 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)

4 dagar ago | 0

| accepted