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Walter Roberson


Last seen: 1 day ago
50,944 total contributions 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.

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Answered
How can I convert an implicit function to an explicit function?
On my system at home, the following program takes less than 6 seconds. However, because I was iterating through versions during ...

4 hours ago | 0

Answered
Why are the legends appearing twice?
Your code is assuming that the audio only has one channel, but instead it has two channels in each file.

5 hours ago | 1

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Answered
How to verify if a row or a column or a cubic 3x3 have a repeated number for sudoku?
Suppose you store NaN for all slots that have not had anything written to them. Then extract the appropriate portion of the arra...

6 hours ago | 0

Answered
How can I find exactly the coordinates of the center of the yellow circle?
You can calculate the center of mass of the image. https://www.mathworks.com/matlabcentral/answers/363181-center-of-mass-and-to...

13 hours ago | 0

Answered
Cycle through graph marks
Create a cell array of linespec (character vectors indicating style and color and marker). Then each time you plot, index into a...

13 hours ago | 0

Answered
Frame Differecning help using matrices and pixels
Replace temp = im2gray(temp); temp2 = frames(:,:,:,l + 1); temp2 = im2gray(temp2); with temp = double(im2gr...

1 day ago | 0

Answered
Error using sym>convertChar (line 1537) when solving an ODE using laplace transform. How to fix the problem?
%%CODE %% Solving 2nd order ODE using laplace transform syms x(t) s X F Dx = diff(x,t); D2x = diff(Dx,t); eqn = D2x + 7*D...

1 day ago | 0

Answered
How can I sort through a set of tables and remove the duplicates?
isequal() can be used to test whether two table() have the same content and same variable names. For efficiency, you can group ...

1 day ago | 0

Answered
Error in my code
uigetfile has two outputs. The second one is the directory. You need to put it together with the file name to get the name to pa...

1 day ago | 0

Answered
Give a specific color to an interval of value
I suggest you use https://www.mathworks.com/matlabcentral/fileexchange/69470-custom-colormap

1 day ago | 0

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Answered
Save Geographic Player Figure as an image
fig = player.Parent; saveas(fig, 'ImageFileName.png')

1 day ago | 0

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Answered
How do i send image trought fsk modulator
Simulink reshape() block. https://www.mathworks.com/help/simulink/slref/reshape.html

1 day ago | 0

Answered
problem in cell matrix operations
Your current code would take 1 row from Coh, then the following 2 rows, then the following 3 rows, and so on. Is that what is de...

1 day ago | 0

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Answered
Solving system non-linear equations
syms x [1 4] sr = sym([0.05 0.1 0.5 1]); Eapp = sym([2.09 2.18 2.27 2.4]).*1e6; Ei = sym(2.55).*1e6; E0 = sym(2.14).*1e6;...

1 day ago | 0

Answered
Appending multiple variables onto a single file
dinfo = dir('*.mat'); filenames = {dinfo.name}; nfile = length(filenames); hasmap = false(nfile,1); for K = 1 : nfile ...

2 days ago | 0

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Answered
what does the function handles do in matlab?
handles is not a function. It is a struct. handles by itself has no special meaning; it could have been called anything. The c...

2 days ago | 1

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Answered
Any value (different values) I enter for TOLERANCE and ITERATION gives the same results(Answer( . It is supposed to give different answers . I don't know why this is occurring.
You exit the loop when you reach the tolerance. What happens if you exit the loop no later than 5 iterations? Then giving 20 in...

2 days ago | 0

Answered
Why does the Fourier transform of a vector cannot tranfroms back into it itself in an exact manner, through ifft(fft())?
Floating point round-off. format long g a = rand(16,1); b = ifft(fft(a))-a; plot(b) [min(b), max(b)] ans/eps The values ...

2 days ago | 0

Answered
Linear Label on Logarithmic Plot
ax = gca; ax.YAxis.Exponent = 0;

2 days ago | 0

Answered
Solving non-linear ODE
Your equation has 1/sqrt(t) and initial t of 0. That gives you 1/sqrt(0) -> 1/0 -> infinity at the start EP_equation functio...

2 days ago | 0

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Answered
Plot function cannot work normally
Your file E:\MATLAB Inc\MATLAB 2018B\toolbox\matlab\graphics\gobjects.m is corrupt. You will need to restore it from backup (if ...

2 days ago | 0

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Answered
too many input arguments error when i pass struct to my function
f = @(x)CostTimeDCal1; That says that when f is called, it should ignore its single input parameter and call CostTImeDCal1 with...

2 days ago | 1

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Answered
how to get keyboard in matlab
psychtoolbox http://psychtoolbox.org/ has several input methods that do not require use of figures to receive typing.

2 days ago | 0

Answered
Matlab gives error on empty line
The important part is Untitled line 43, which is the assignment to K_fc . On that line you have three places where you have ex...

2 days ago | 1

Answered
Remove Figure window from appearing at all in program
Correct, if you set a figure visibility off, then the sequence of code you use will not display it to the screen but will save i...

2 days ago | 1

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Answered
Index exceeds the number of array elements (2)
y(6) Your code expects 6 (or more) boundary conditions are going to be passed in y0 = [L*cos(alfa);L*sin(alfa)]; but ...

3 days ago | 1

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Answered
How to evaluate a function that has been saved to a variable
%provided that x is symbolic d1(x) = diff(f(x)) d2(x) = diff(f(x),2) d3(x) = diff(f(x),3)

3 days ago | 2

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Answered
Getting Input Error With Code
You need to rearrange your code. DissMale = abs(.50 - Crime_Male); DissFemale = abs(.50 - Crime_Female); [R,C] = size(DissMal...

3 days ago | 0

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Answered
Solutions are only valid under certain conditions
You can get four solutions. However, the solutions will be effectively useless, and the conditions under which they apply will b...

3 days ago | 0

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Answered
How to reconstruct a matrix?
x = [8, 9, -3, 9, 5, -4, -1, 3, 10, 10]; y = [-6; 4; 4; -2; 2]; z = [diag(y), x(1:5).'; x(1:6)]

3 days ago | 1

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