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Walter Roberson


Last seen: Today
48,551 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
Undefined variable "dsp" or class
You need to license and install DSP System Toolbox; https://www.mathworks.com/products/dsp-system.html

16 minutes ago | 0

Answered
Is it possible to install and run MATLAB R2020b on NVIDIA Xavier platform?
You are right, at present MATLAB is only supported on Intel platforms. Next month (December 2020), Mathworks intends to release...

18 minutes ago | 0

Answered
Unable to perform assignment because the left and right sides have a different number of elements.
When you enter 7 then the code expects to read 7 lines with 8 values per line (though as the prompts hint you can put as many va...

5 hours ago | 0

Answered
Creating a symbolic array
a = sym([]); or better yet a = zeros(5,5,'sym')

5 hours ago | 0

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Answered
Need help in viewing a 2D image in 3D space.
volumeviewer perhaps. But I suspect idx = find(YourMatrix) ; [r, c, p] = ind2sub(size(YourMatrix), idx); scatter3(c, ...

10 hours ago | 0

Answered
How to write if statement for logical value
any(Result{1,1}, 1)

10 hours ago | 0

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Answered
GA does not solve problems with integer and equality constraints.
you can still use ga but you have to tell ga that you have no integer constraints. Then you have to provide a population functio...

10 hours ago | 1

Answered
Error using sym/subsindex () while using the symsum function
You can never use an unresolved symbolic variable as a subscript. You must always use definite numeric or logical values for ...

10 hours ago | 0

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Answered
Error in Cumtrapz?
Remember after one integration you get a formula with a constant of integration, and when you integrate that, you get the double...

23 hours ago | 0

Answered
How to remove duplicates from a matrix without using unique?
[~, a]=findgroups(d);

1 day ago | 1

Answered
or() in categorical variable
ismember(financial_status, 1:2) At the moment I cannot think of any computer language that expresses a set membership test ...

1 day ago | 0

Answered
can matlab calculate the area of irregular shape base on 2D-grid ?
No, in the general case the area of irregular shaped objects is not defined. See https://en.m.wikipedia.org/wiki/Koch_snowflake ...

2 days ago | 0

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Answered
Resizing the images to 100 x 100
TestData.Files(1:20) = cellfun(@(I) imresize(I,[100,100]), TestData.Files(1:20), 'uniform', 0); The code would have been sh...

2 days ago | 0

Answered
how does sum work?
you have one / operator that should be ./

2 days ago | 0

Answered
GA Toolbox maximization fucntion
To maximize a function, minimize the negative of the function @(x) -f(x)

3 days ago | 1

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Answered
можно ли сделать так, что бы сетка отображалась поверх 3D графиков?
fig = figure(); ax1 = axes('Parent', fig); [X, Y] = meshgrid(1:50, 1:60); Z = X.^2 + Y.^2 - cos(X.*Y); surf(ax1, X, Y, Z, ...

3 days ago | 0

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Answered
how to compand the complex valued signal
https://www.mathworks.com/help/comm/ref/compand.html#fp1068641 Look in the Algorithms section, which gives the formulas. Thos...

4 days ago | 0

Answered
Plot of an equation of three unknown variables
http://www.mathworks.com/help/matlab/ref/slice.html http://www.mathworks.com/help/matlab/ref/isosurface.html For a full plot o...

4 days ago | 0

Answered
what does this line do
The code goes through all of the F cell entries, and finds the number of columns in each, recording the number of columns in num...

4 days ago | 0

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Answered
Coding an equation (with summation within equation) with nested for Loops
You are probably summing T_xt(:,:,:) over the third dimension to get T(x,t) . However, when you do that, you would be adding T_...

4 days ago | 0

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Answered
Matlab solver for natural log equation
Q = @sym; %convert to rational syms x eqn = log(Q(0.5)) == (-Q(27109)/x)-Q(0.95)*log(x)+Q(25.18) S = solve(eqn,x) vpa(S) ...

4 days ago | 0

Answered
How to use parfor instead of for in this function
That is not possible. The output when i=2 depends on y(:,2) having been set properly, but y(:,) has not been assigned to until i...

5 days ago | 0

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Answered
How to vectorize this for loop
Fea = Fin( sub2ind(size(Fin), SD(1:10,:), 20*ones(10, size(SD,2)))); However, your original code would have failed. Your SD is ...

5 days ago | 0

Answered
Insufficient number of outputs
a=imread('emptybottle.png'); b=rgb2gray(a); f1 = imcrop(b,[400 0 200 130]); imhist(f1); f2=im2bw(f1,0.78); f3=~f2; im...

5 days ago | 0

Answered
how to find kshortest path or use Dijkstra algorithm for 12 plot points.
ps=[37 316]; pg=[382 471]; b1=[71 319]; b2=[105 379]; b3=[74 281]; b4=[340 339]; b5=[338 280]; b6=[48 125]; b7=[181 176...

5 days ago | 0

Answered
not enough input arguments
>> classifyKNN_D_Multi You are trying to run a function that requires either 4 or 5 inputs, with no inputs at all. case ...

6 days ago | 0

Answered
using fit function,Error using fittype
D(x) = (20*gc*exp(gd*x))/(gc + gd - gu) - (20*gc*exp(-x*(gc - gu)))/(gc + gd - gu) That is a symbolic function involving thr...

6 days ago | 0

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Answered
How to find the difference between two plots while the dimension of the matrices are different?
subplot(1,2,1) plot(x1, y1, 'b', x2, y2, 'r') subplot(1,2,2) minx = max( min(x1), min(x2) ); maxx = min( max(x1), max(x2...

6 days ago | 0

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Answered
Professor Provided this code but I cant get it to run
% assign numerical values to global variables U, Ta , % to be able to use such values in all sub - programs % that include the...

6 days ago | 0

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