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Walter Roberson


44,549 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
Genetic Algorithm Optimizatioin - Error
D:\Matlab\mrst-2018a\modules\octave\rng.m You need to get that off of your MATLAB path. There is also a fair risk that other ...

6 hours ago | 0

Answered
How to solve nonlinear equation with unknown variables?
No, it should not give you a real number. You did not tell MATLAB that x is restricted to reals, so it is proper that solve() re...

9 hours ago | 0

Answered
Why .fig file looks different in different MATLAB versions ?
As of R2014b, Handle Graphics 2 (HG2) started being used. One aspect of HG2 is that uicontrols no longer automatically render on...

11 hours ago | 0

Answered
How to find index of rows without -999
find(~any(YourArray == -999,2))

16 hours ago | 0

| accepted

Answered
Make comet move with respect to a function
You cannot do that with comet(). comet() requires that you pre-define all of the points, and it moves them however fast it wants...

16 hours ago | 0

Answered
save a probability matrix (range [0, 1]) as grayscale image with range [0,1]
For the low level stuff: https://www.mathworks.com/matlabcentral/answers/7184-how-can-i-write-32-bit-floating-point-tifs-with-n...

17 hours ago | 0

Answered
index exceeds array bounds
disp=("Acceleration is now equal to: ") That line redefines disp from being a function into being a scalar string object. You n...

17 hours ago | 1

Answered
editing a string using GUI editable text/popup within guide
user_input_food = handles.food_textbox.String; %assuming you named the edit uicontrol food_textbox user_input_amount = h...

18 hours ago | 0

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Answered
index variable based on time points
output = zeros(size(mri,1), size(mri,2), 35, 40, class(mri)); for t = 1 : 40 output(:,:,:,t) = mri(:,:,35*(t-1) + (1:35));...

18 hours ago | 0

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Answered
Minimize Function with multiple inputs
We end up with a fuel flow rate, which I need to minimize by variying the 4 variables. You have a single objective. You can use...

18 hours ago | 0

Answered
What plans are there for native support on ARM v8 64 bit CPUS
You need to contact your sales representative and enter into a Non-Disclosure Agreement to get information on that topic. My own...

19 hours ago | 0

Answered
how to evaluate definite integral
Your ep is 1 x 11 so for each scalar x your f would want to return 1 x 11. integral() does not expect that: integral() expects t...

19 hours ago | 0

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Answered
Trouble with 'global' & 'ode45' with plot in TDM spr-mass-damp. system
[t,x] = ode45(@ydot,(0:1),[0 0 0 0]); z = x(((3/4)*end:end),1); When you pass a vector of exactly 2 elements in as the...

19 hours ago | 0

Answered
How to reduce For loop execution time?
>> tic;s = sum(exp(-sum((reshape(proc(1:3), [], 1) * (1:1000000000)).^2))); toc Elapsed time is 55.136908 seconds. This was sl...

19 hours ago | 0

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Answered
How to change block order between MatLab Sessions (Psychtoolbox)
rng('shuffle') seeds the random number generator based on the current time so that RAND, RANDI, and RANDN produce a dif...

21 hours ago | 0

Answered
This error keeps popping up and I have no idea why: Error using viscircles Expected input number 1, centers, to be real. Error in viscircles>validateCentersAndRadii (line 283) validateattributes(centers,{'numeric'},{'nonsparse','real', ... Erro
You did not give us any values to test with for A, B, C, D E = sqrt(A^2 + D^2 - 2*A*D*cos(theta)); Looks like the area of a tr...

1 day ago | 0

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Answered
why save '.mat' as 'ascii' file appears as FILE instead of txt
filename1 = fullfile(name_folder_new,'coefficients_m'); No file extension is put on by default when you do that, so MS Windows ...

1 day ago | 1

Answered
bitxor of two numbers
c = typecast( bitxor(typecast(x, 'uint64'), typecast(y, 'uint64')), 'double'); Expect to see a lot of values in the range 1e-30...

1 day ago | 0

Answered
Replacing <undefined> in categoricals or defining a default value
YourTable.parttype = fillmissing(YourTable.parttype, 'constant', '-empty-');

1 day ago | 0

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Answered
polyeig gives different eigen values for the same matrices.
In spite of the fact that both set of matrices are exactly the same But they are not. >> isequal(GLC,gld) ans = logica...

1 day ago | 0

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Answered
How can I open multiple bin files from one folder with uigetfile command?
When you use multiselect in uigetfile, then you need to use something like if isnumeric(filename) disp('User selected ''Can...

1 day ago | 0

Answered
Classification accuracy change every time
Classification app and the functions reached from nnstart all initialize randomly. If you need to be able to reproduce every tim...

1 day ago | 0

Answered
Find position of max value in a graph
[max_xphi, maxidx] = max(xphi); phi_at_max_xphi = phi(maxidx); The maximum is at x = phi_at_max_xphi, y = max_xphi

1 day ago | 0

Answered
Student Licence obtention for engineer trainee
You cannot use a student license for that purpose. Student licenses must be installed only on equipment that is owned (or leased...

1 day ago | 0

Answered
Vector output from a for loop
TMP_values = [12, 3, 36]; num_TMP = length(TMP_values); PGRED = zeros(1, num_TMP); for TMP_idx = 1 : num_TMP TMP = TMP_v...

1 day ago | 1

Answered
save spacific entity from matrix
After your T=Rob.fkine([th_1 th_2 th_3]); Add TM = T.T; Now you can access TM(1,4)

1 day ago | 0

Answered
How to replace last 3 digits in a floating point number by another 3 digits
>> fprintf('%.999g\n', -3.141592653589793) -3.141592653589793115997963468544185161590576171875 The last 3 digits of x are 875 ...

1 day ago | 1

Answered
How to use external function in matlab guid?
You get the error because you either do not have Image Processing Toolbox installed, or else you do not have a license for it.

1 day ago | 0

Answered
Load a bunch of ASC files and save the results in a MAT file
If you are willing to assign a fixed maximum length to each text field, and the format of the lines is predictable, then in some...

1 day ago | 0

Answered
is it possible to call variable from text in MATLAB Live Script ?
n = 3; fprintf('In order to find the output, you must divide the input with the value "%d".\n', n); See also compose()

1 day ago | 0

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