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

Programming Languages:
C++, C, MATLAB, Shell, Perl, Fortran
Spoken Languages:
English

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Answered
Surface plot error for Z must be a matrix, not a scalar or vector
careful, x is (eventually) going to be 3d, and the way you use size is wrong for 3d. I have seen cases where z was returned a...

alrededor de 2 horas ago | 0

Answered
(HOW) I need the code run again if the ( else condition return ) till give me value
do_again = true; while do_again do_again = false; for i= 1:7 for j=1:7 if (i~=j) if % coditi...

alrededor de 5 horas ago | 0

Answered
Is there a way to overlay a graph onto a video, plotting each successive point with each frame?
I recommend videofig() from the File Exchange. https://www.mathworks.com/matlabcentral/fileexchange/29544-figure-to-play-and-ana...

alrededor de 5 horas ago | 0

Answered
Compute operation with different index (part II)
It would be easier if you would switch over to table or timetable instead of using timeseries . filename = 'https://www.mathwor...

alrededor de 5 horas ago | 0

Answered
warning message using surf
We cannot tell what length(u) or length(v) or size(Xq) or size(Yq) is. You could get an error if size(Xq) is not the same as si...

alrededor de 5 horas ago | 0

Answered
How to change patient name?
P = zeros(256, 256, 263); for K = 263 : -1 : 1 petname = sprintf('%03d.dcm', K); info(K) = dicominfo(petname); So in...

alrededor de 6 horas ago | 0

| accepted

Answered
Solve taking too long, how to optimize code?
k = 180; length = .05; b = .01; T0 = 180; Tinf = 25; h = 25; Tsurr = 290; epsilon = 0.9; theta = atan((b/2)/length); ...

alrededor de 7 horas ago | 0

Answered
Can you give me the code for Stabilogram Diffusion Analysis (SDA)?
<https://isbweb.org/software/movanal/stamp/>

alrededor de 9 horas ago | 0

Answered
Unable to read UDP data with parfeval
When you use parpool (at least if you do not use the "threads" option, not sure about threads), then the workers are in a separa...

alrededor de 11 horas ago | 1

Answered
GUI new callback name
I can tell that you are using a GUI created with GUIDE. Edit ConvertMatLab_gui.m Near line 31 you will find lines % Begin in...

alrededor de 11 horas ago | 1

Answered
It's a question about menu function.
Each time menu() is called, it creates a new figure() .

alrededor de 12 horas ago | 0

Answered
Import txt file into MATLAB for Comparison of 2 files to measure bit errors
B1 = fileread('1.txt') - '0'; B2 = fileread('2.txt') - '0'; L1 = length(B1); L2 = length(B2); if L1 ~= L2 fprintf('fir...

alrededor de 12 horas ago | 0

Answered
how to decrease the x-axis from left to right
set(gca, 'XDir', 'reverse')

alrededor de 12 horas ago | 0

| accepted

Answered
Convert a Cell array with char and white spaces to Cell array with double without white spaces
filename = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/750699/sample%20data.xlsx'; opt = detectImportOption...

alrededor de 12 horas ago | 0

| accepted

Answered
What " lo=3 " means in system option???
https://www.gams.com/34/docs/UG_GamsCall.html lo=3 means all of the output of the executable is to be written to "standard out...

alrededor de 22 horas ago | 0

| accepted

Answered
how to delete repeated rows in a table?
format long g M = [518460 3.322; 518460 -12.984; 518520 3.798; 518520 -10.28; 518580 7.763; 518580 16.851; 518640 5.959; 522225...

alrededor de 22 horas ago | 1

Answered
Matrix Dimensions must Agree
Your D_pca has 4 rows and an unknown number of columns. Your eigvects has 2 rows and an unknown number of columns. D_pca(:,1)*...

alrededor de 22 horas ago | 1

| accepted

Answered
multiply by two matrix
syms x n = [1.521, 2.66]; k0 = 1; h = [1.5e-6, 1e-6]; k = @(j) sqrt(n(j).^2*k0.^2-x.^2); M = @(j) [ cos(k(j) ....

alrededor de 22 horas ago | 0

Answered
Trying to compress a signal.
compressed_x = x(1:2:end);

alrededor de 22 horas ago | 0

| accepted

Answered
Plotting function, which includes a sum
When you provide a start value, you also have to provide a count -- even if you just provide inf as the count.

1 día ago | 0

Answered
absolute value in equality constraints
N = 5; var10 = optimvar('var10', N); var9 = optimvar('var9', N); var7 = optimvar('var7', N); prob = optimproblem; ABS = @...

1 día ago | 0

| accepted

Answered
How can I check if the columns of my matrix have value in common?
I am not certain what you are asking Either a value from the sixth column in all five first or subsequent columns. M = randi(2...

1 día ago | 1

| accepted

Answered
AppDesigner press 'Enter' key to stop edit-field type in
Use 'ValueChanged' callback instead of 'ValueChanging' https://www.mathworks.com/matlabcentral/answers/458098-difference-betwee...

1 día ago | 0

| accepted

Answered
solve the equation for a large frequency range
Rsh=0.01*pi Lsh=5*10^-9 freq=1e+3:1e+8;%frequency range Rsh=0.01*pi; d=Rsh+(2*pi*freq*i*5*10^-9); factor = Rsh ./ d; In M...

1 día ago | 0

Answered
Add missing numbers of 0's and 1's in an array
M = [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0]; zstarts = strfind([1 M], [1 0]) zend = strfind([M 1], [0 ...

1 día ago | 0

Answered
Is it posible to change the number of digits Matlab works with?
You would have to use the Fixed Point Toolbox. This might require some modifications to QuTip toolbox; Fixed Point Designer woul...

1 día ago | 0

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Answered
matlab error: defined variable after local function definition
You have to move the lines x = linspace(0,500,1); T = linspace(0,500,1); m=0; sol = pdepe(m,@pdex1pde,@pdex1ic,@...

1 día ago | 1

Answered
asalam.A.
%x'y'z' + x'y'z + x'yz + xyz' [x, y, z] = ndgrid([false true]); x = x(:); y = y(:); z = z(:); actual_output = (~x & ~y & ~z...

1 día ago | 0

Answered
Why I can't open csv from matlab live script?
You tried to convert csvread() to readmatrix(). csvread() permits you to pass a parameter that is the number of rows to skip, an...

1 día ago | 0

| accepted

Answered
I need to find the probability of an event happening given the population mean, a sample size and how many times I need it to happen
p = 0.9/9000 n=5 N=2415 P = p^n*(1-p)^(N-n) * C(N, n) where C(a, b) is a!/(b! (a-b)!) except you need to implement...

2 días ago | 0

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