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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.

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Answered
Obtain 2x2 regions in an image using sliding window
If all you are doing is "observing" the pixels, then a double-nested loop is probably easiest; the time taken to "observe" them ...

36 minuter ago | 0

Answered
How can I execute the “sound” function in matlab and then execute the rest afterwards? (Blocking)
sound() cannot be made blocking. In your situation, if you have the DSP toolbox then dsp.AudioDeviceWriter https://www.mathwork...

42 minuter ago | 0

Answered
fsolve residue almost zero error, I calculate and find errors
I speculate that you have format short in effect (because it is the default), and that you are taking the 4-decimal-place res...

ungefär 3 timmar ago | 0

Answered
Convert an array of type char to hex values
I showed you a number of different methods in https://www.mathworks.com/matlabcentral/answers/888752-quickest-way-to-convert-hex...

ungefär 3 timmar ago | 0

Answered
Cell array of matrices to multi-dim matrix
k = randi([3 6], 1) j = randi([3 6], 1) c = randi([3 6], 1, k) m = randi([2 5], 1, j) C = cell(c); C = cellfun(@(~) randi(9...

ungefär 6 timmar ago | 0

Answered
How to count the numbers before consecutive negative values?
c = [ 0.4855 -0.1902 -0.1758 0.3935 -0.1264 -0.1274 -0.0914 -0.1149 -0.0930 0.5572 0.5098 1.0000 ....

ungefär 7 timmar ago | 0

Answered
Replacing function variables with a vector before taking a gradient
syms x1 x2 x3 x4 real syms C1_0 C2_0 x=[x1,x2,x3,x4] A = subs(A, [C1, C2, R1, R2], [C1_0, C2...

ungefär 7 timmar ago | 0

Answered
How should i solve a system of non-linear equations and then plot the interdependence of any two variables? Can i use vpasolve?
If you have equations that have a finite number of solutions, then: * if the equations are multinationals then in theory matl...

ungefär 13 timmar ago | 0

Answered
do not figure out errors in xlim
z2 is the last entry from z1. The last entry from an array cannot be strictly greater than the array: it is guaranteed to equal ...

ungefär 13 timmar ago | 0

Answered
Install add-ons through commandline/headless?
It is possible, using matlab.addons.install() https://www.mathworks.com/help/matlab/ref/matlab.addons.install.html However, t...

ungefär 23 timmar ago | 0

Answered
how to get the position of a line in from a 2D matrix data.
See improfile() https://www.mathworks.com/help/images/ref/improfile.html#d123e161936 Note that you pass in endpoints of line s...

ungefär 23 timmar ago | 0

Answered
How to do iteration until certain tolerance is achieve?
while abs((psic/psit)+(1/(2*sigma)))<tol That tells us that you are looking for (psic/psit)+(1/(2*sigma)) to become as close to...

ungefär 23 timmar ago | 0

Answered
How do I gapfill a vector only if gaps (NaNs) are 10 elements or less?
format short N = 10; x = [1,2,3,5,7,9,10,9, NaN,NaN,5,3,2,NaN,NaN,NaN,NaN,NaN,NaN,NaN,NaN,NaN,NaN,NaN,12,13,14,15,16]; mask...

ungefär 24 timmar ago | 0

Answered
Getting different results from function handle & syms for a same equation. How to avoid it?
Remember that when you mix floating point numbers into a symbolic expression, that MATLAB uses the default conversion of floatin...

ungefär 24 timmar ago | 0

Answered
fsolve stopped because the problem appears regular
format long g omega0=2*pi*599.585e12; data=(2+0.5i)^2; syms x [1 2] rf = rfpnk(x,omega0,data) sol = solve(rf) [sol.x...

en dag ago | 0

| accepted

Answered
Combining two surface plots
You can ax = gca; yellow = surf(ax, x, p, a); hold(ax, 'on') M = [1 0 0 1; 0 0 1 0; 0 1 0 0; 0 0 0 0]; hg = hgtransform(ax,...

en dag ago | 0

Answered
I want to generate Three different random Communication Channels and sort it. Please help
h1=(randn(1)+1j*randn(1)); h2=(randn(1)+1j*randn(1)); h3=(randn(1)+1j*randn(1)); z=sort([h1,h2,h3]) Note that by default, so...

en dag ago | 0

| accepted

Answered
What is the difference between the effect of clear and clearvars?
@Kien Pham asked above whether there was a timing difference between clear and clearvars. The answer astonished me: there is a ...

en dag ago | 1

Answered
plz help how can use go to in MATLAB
MATLAB itself does not have a GO TO, and never will. Simulink diagrams sort of have a GO TO but it does not affect flow of co...

en dag ago | 0

Answered
Getting error message, "Execution of script bar as a function is not supported".
which -all bar will show you that you have a bar.m in your path that is not the Mathworks bar function

en dag ago | 1

| accepted

Answered
How do I get a "≤" sign to appear in my function's HELP documentation?
<= is not part of CP1252 https://en.wikipedia.org/wiki/Windows-1252 I am using 2016b In that release, MATLAB did not use UT...

en dag ago | 0

Answered
how to count further?
Where do you transition from state2 to something else? Are you trying to count all the rising edges, ignoring the falling edges...

en dag ago | 0

Answered
quickest way to convert hex to a 16 bit signed integer
format long g N = 100000; HC = ['0':'9', 'A':'F']; data = HC(randi(16, N, 4)); timeit(@() typecast(uint16(hex2dec(data)),'...

en dag ago | 1

Answered
Left and right sides have a different number of elements
x=[11500.2 11477.9 11417.3 11426.4 11413 11382.9 11375.1 11347.9 11351.1 11329.3 11318.9 11343.4 11360.7 11378.4 11414.2 11408.2...

2 dagar ago | 0

Answered
Could anyone help me how to save the bar graph in png format.
%applyhatch is a File Exchange Contribution. We need to install it to %generate the graphics to demonstrate the save techniques...

2 dagar ago | 0

Answered
If you're using tic, toc, and var=input('prompt'), is there a way for toc to interrupt the user input if they take too long to answer?
Two timer based solutions are shown in https://www.mathworks.com/matlabcentral/answers/119067-how-can-i-set-a-time-for-input-wai...

2 dagar ago | 0

Answered
Could someone explain the error: "Array indices must be positive integers or logical values," and also how I'd go about fixing it?
contents = cellstr(get(hObject, 'string')); UnitType = contents(get(hObject, 'Value')); In the situation where nothing is sele...

2 dagar ago | 0

Answered
Assignment between unlike types is not allowed for two function in a loop
It looks like your function is returning struct variables. When you have code of the form struct1(index) = struct2 wh...

3 dagar ago | 0

| accepted

Answered
Error while evaluating UIControl Callback.
You need to contact your company to have them authorize you to use that toolbox.

3 dagar ago | 0

Answered
Using linspace outside of field data areas?
Use scatteredInterpolant() with the Extrapolation Method set to 'none'

3 dagar ago | 0

| accepted

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