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

Statistics

All

View badges

Content Feed

Answered
How to set boundary for solutions in vpasolve?
There does not appear to be a solution between 1.3 and pi/2 radians. Tp = 1 ; Tg = 1.3 ; Te = 1 ; Vp = 480 ; Vg = 587 * (...

6 hours ago | 0

Answered
What is main difference between Academic and Student License?
All three of those toolbox can be purchased for a student license https://www.mathworks.com/store/link/products/student/SV?s_ti...

6 hours ago | 0

Answered
Porqué tengo error en línea 17 del código? o existe otro error
syms x f=x.^8-7*x.^3 + 7; d=diff(f); d is a symbolic expression in x xo=xo-lambda*d; That symbolic expression in x is u...

8 hours ago | 0

| accepted

Answered
i'd like to ask is there any function to find asymptotes of an equation y = f(x) that satisfies x = x(t) and y = y(t). I'm new to matlab.
syms t; x_t = (t+1)./(t-1); y_t = (t^2 + 2)./(t^2 - t); limit(y_t, t, -inf) limit(y_t, t, 0, 'left') limit(y_t, t, 0, '...

9 hours ago | 0

Answered
Code runs but no graphical output
E = 200000; % Young's Modulus in N/mm^2 I = 416.667; % Moment on Inertia in mm^2 P = 600; %Applied force in N Q = 1200; %Appl...

11 hours ago | 1

| accepted

Answered
Arrays have incompatible sizes for this operation.
% Number of points on the ellipse N = 8; % Parametric representation of the ellipse theta = linspace(0, 2*pi, N); x = cos(th...

11 hours ago | 0

Answered
Why do I receive error stating that function needs to appear at the end of the file? MATLAB Differential Equations Help
It is just a Fact Of Life with MATLAB. You have some non-function statements, then you define a function, then you end the funct...

13 hours ago | 0

Answered
How do I get normal numerical answers using solve or vpasolve?
Use sym(pi,'d') instead of pi Or... use sympref to set floating point output on Or... Use vpa Or... Use double. For examp...

22 hours ago | 0

| accepted

Answered
Good evening. If possible, I would like a comprehensive explanation of cell-free technology in 6G. If there is a MATLAB code available with it, I would be very grateful.
An explanation of cell-free technology is a large topic that is beyond the scope of MATLAB Answers. Providing MATLAB code for a...

23 hours ago | 1

Answered
Can I upload excel input and output data in PSO to define objective
Yes. It is inefficient to do this for inputs; you should instead read the data once before the pso() call and use function para...

23 hours ago | 0

Answered
error: Undefined function 'on' for input arguments of type 'double'. How can i fix this error (i use matlab app designer)?
typefunction = app.TypefunctionEditField.Editable; fxi=str2func(typefunction); typefunction contains something that includes...

23 hours ago | 0

Answered
I have 4 inputs (P,T,V,H) and 1 output (TS). I want to optimize for TS (maximize in this case). Can I use PSO for this purpose
Yes you can. You might find it easiest to use Problem Based optimization.

23 hours ago | 0

| accepted

Answered
I code a bisection method on MATLAB app designer, how can I fix this error ?
fxi=str2func(['@(x)'typefunction]); You need a space or comma, like fxi=str2func(['@(x)' typefunction]);

1 day ago | 0

Answered
Ode45, Events error: SWITCH expression must be a scalar or a character vector
I have seen this before when the person had a third-party version of lower in their MATLAB path. Please show which -all lower ...

1 day ago | 0

Answered
Generate specific binary combination
N = 4; for K = 0 : 2^N - 1 thiscombo = dec2bin(K,N); stuff end

1 day ago | 1

| accepted

Answered
selected cell in table app designer
https://www.mathworks.com/help/matlab/ref/matlab.ui.control.table-properties.html#mw_1135e93c-c65f-4439-9112-dc80ae0d6d65 Selec...

1 day ago | 0

| accepted

Answered
I don't know how to solve the error it is producing
fun = @(b, t) cost(db, tb, P, E, H, rho, numIters, segments); fun is a function that expects two parameters, and ignores both o...

1 day ago | 0

Answered
Need to simulate a keypress in a matlab script
https://www.mathworks.com/matlabcentral/fileexchange/28603-inputemu-keyboard-mouse-emulator-v1-0-1 https://www.mathworks.com/m...

1 day ago | 0

| accepted

Answered
Issues with surface plotting using a large table of data
surf(vector_of_length_54, vector_of_length_12, Your_12_by_54_data) Remember that horizontal (rows) corresponds to Y axes, and v...

1 day ago | 0

Answered
LDPC encoding using MATLAB encoder
I = randi([0 1],43200,1); % INFORMATION BITS H = dvbs2ldpc(2/3); l = comm.LDPCEncoder(H); codeword = l(I);

1 day ago | 1

| accepted

Answered
Why these two path strings are different? (manual string vs. pwd + fullfile)
You will find that on MacOS and Linux (including here on MATLAB Answers) that fullfile uses / separators

2 days ago | 0

Answered
Direct calculations on tables - elementwise mean of n-tables
cellfun table2array, cat(3) the expansion of the resulting cell, mean() across the third dimension. array2table the results givi...

2 days ago | 0

Answered
Is there a uicontrol to let user rearrange rows of strings?
No there is no uicontrol for that purpose.

2 days ago | 0

| accepted

Answered
Why I can not start the parpool? I just upload the MATLAB and Toolbox, is this question related to the Lenovo system?
<https://www.mathworks.com/matlabcentral/answers/647218-invalid-character-code-sequence-detected-error-using-parfor-on-matlab202...

2 days ago | 0

Answered
sympref FloatingPointOutput adds roundoff error
That does not happen in current releases, so it must have beeen fixed between R2020b and R2023b format short e u = symunit; ...

2 days ago | 0

Answered
Is there a way to capture the user click on a LiDAR plot?
See https://www.mathworks.com/matlabcentral/answers/62653-convert-currentpoint-to-x-and-y-value#answer_74247 CurrentPoint ref...

2 days ago | 0

Answered
can I ask a several question about automatic control ?
syms u(t) y(t) sigma omega_n dy = diff(y,t) d2y = diff(dy, t); eqn = d2y + 2*sigma * omega_n * dy + omega_n^2 * y == omega_n^...

2 days ago | 0

Answered
I need to plot a graph for this physics problem and I don't know how to do it.
By knowing the cutoff height you can calculate the radius of the circular opening. By knowing the cutoff height you can calcuat...

2 days ago | 0

Answered
is there a way to perform this task w/o using loops?
The more general vectorized strategy would probably be to set up cell arrays of values, and then use the fact that when you stru...

2 days ago | 0

Answered
trouble making a firfilter to remove a tone out of a wavefile
The error is correct, in that the documentation lists specific filter specifications, none of which include Fc https://www.math...

2 days ago | 0

| accepted