# 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 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**

RANK**1**

of 284,544

REPUTATION**133,997**

CONTRIBUTIONS

**37** Questions

**59,372** Answers

ANSWER ACCEPTANCE **
48.65%
**

VOTES RECEIVED**17,943**

RANK

of 19,212

REPUTATION**N/A**

AVERAGE RATING**0.00**

CONTRIBUTIONS**0** Files

DOWNLOADS **0**

ALL TIME DOWNLOADS**0**

CONTRIBUTIONS**0 Posts**

CONTRIBUTIONS**0** Public Channels

AVERAGE RATING

CONTRIBUTIONS**0** Highlights

AVERAGE NO. OF LIKES

**Content Feed**

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Generate specific binary combination

N = 4; for K = 0 : 2^N - 1 thiscombo = dec2bin(K,N); stuff end

1 day ago | 1

| accepted

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

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

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

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

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

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

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

Is there a uicontrol to let user rearrange rows of strings?

No there is no uicontrol for that purpose.

2 days ago | 0

| accepted

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

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

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

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

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

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

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