Walter Roberson

Last seen: 1 dag ago | Active since 2011

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sic hoc lorem

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

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Answered
Is vectorization worth the trouble with recent MATLAB?
Let us take an example: finding the row indices of the first non-zero row in a 2D matrix. A = full(sprand(10000,500,0.1)); Loo...

1 dag ago | 0

Answered
Creating a License manager for a MATLAB app
Mathworks does not provide any particular interface to license managers of any sort. It just provides methods to call external f...

1 dag ago | 0

Answered
Filtering column 2 and keeping column 1
mask = filteredData >= THRESHHOLD; selected_time = rawData(mask,1); selected_filtered_data = filteredData(mask); However, i...

1 dag ago | 0

Answered
Chase plot changes figure size internally
frame2 = getframe(ax2); writeVideo(vidObj2, frame2); You are fetching graphics data from an axes. It turns out, howeve...

2 dagen ago | 0

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Answered
The problem is that when I use vpa(U(x,t), 7) to get the solution with 7-digit decimal precision, MATLAB still outputs a very long and complicated expression. how do I fix it?
Observe: a1 = vpa(sym(pi), 7) a2 = vpa(a1, 10) a3 = vpa(a2, 15) a4 = a3 - pi double(a4) From this we deduce that vpa() co...

3 dagen ago | 0

Answered
How to avoid scientific notation in stackedplot?
h = stackedplot(....); oldstate = warning('off','MATLAB:structOnObject'); hstruct = struct(h); warning(oldstate); arrayfun(@...

3 dagen ago | 0

Answered
Adding a circle in a 3D surface plot, viewed in 2D
If you are using fplot() then you need to ensure that some of your Z values are below 0 in the region you are drawing the circle...

3 dagen ago | 0

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Answered
fixed color scale with volshow
After you getframe(fig) use rescale() specifying "InputMin" and "InputMax"

3 dagen ago | 0

Answered
Aquiring images from mobile camera is too slow
Possibly. You might be able to use the IP Camera support Android: https://www.mathworks.com/help/matlab/supportpkg/acquire-imag...

3 dagen ago | 0

Answered
mcap file to mat file
https://www.mathworks.com/matlabcentral/answers/1941419-when-do-i-expect-to-get-support-for-mcap-rosbag-files#answer_1522840 @...

4 dagen ago | 0

Answered
Scripts compiled with mex not accessible from parpool declared as "Threads" instead of "Processes"
https://www.mathworks.com/help/matlab/matlab_prog/run-functions-on-threads.html#mw_1cce412a-b5cb-42a4-b0b3-335654833576 Check ...

4 dagen ago | 0

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Answered
Unrecognized function or variable 'scope'. error in matlab script
The model probably has "single simulation output" configured for it; https://www.mathworks.com/help/simulink/slref/simulink.simu...

6 dagen ago | 1

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Answered
Initial convergence mixed integer ga optimization - only unfeasible results?
If the member is infeasible, the penalty function is the maximum fitness function among feasible members of the population, plus...

6 dagen ago | 0

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Answered
I am trying to incorporate multiple IF statements in my ODE to generate a single output.
The mathematics of ode45 and similar routines is such that the second derivative of the input expressions must be continuous ove...

7 dagen ago | 2

Answered
How to specify intervals of increasing, decreasing of a function in MATLAB
Start at the left end of the interval. Record sign() of dy there, along with the current position. Move right one position. Calc...

7 dagen ago | 1

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Answered
How to get mod symbol
title('$||\nabla||$', 'interpreter', 'latex')

7 dagen ago | 0

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Answered
I want to make that makes graph move with a direction keyboard.
The easiest way is to have a figure, and attach a KeyPressFcn property to the figure; https://www.mathworks.com/help/matlab/ref...

7 dagen ago | 1

Answered
plot a surface from a three variable table
If not the below code, then use meshgrid instead of ndgrid This code takes a long time to execute !! The internal triangulation...

7 dagen ago | 0

Answered
latex interpreter greek symbols
https://www.mathworks.com/help/matlab/creating_plots/greek-letters-and-special-characters-in-graph-text.html Use \nabla

8 dagen ago | 0

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Answered
Trouble using container with cell type for key and structure array for values..
struct values are not permitted. keys = 100:110; values = struct('abc', num2cell(1:11)) containers.Map(keys, values)

9 dagen ago | 0

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Answered
How to call .dll without header file
The header files is necessary for identifying function "signatures" -- knowing what datatype each function parameter is. So the...

9 dagen ago | 0

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Answered
I cannot find R2023a installer. In the drop-down, there is only R2024b.
That can happen if you do not have a MATLAB license registered against your MATLAB Central account.

9 dagen ago | 1

Answered
Error using mupadengine/feval_internal Arithmetical expression expected.
According to a previous thread, the problem is that one of the expressions generates NaN

9 dagen ago | 0

Answered
Not able to get local and absolute max or min of a function or graph symbolically
[num, den]=numden(dy); dy_den=diff(den); % % Case1: If denominator in y' is a constant if dy_den==0 In general, t...

12 dagen ago | 0

Answered
Failed to convert matlab function to dll
NAN and INFINITY is not constant and they actually identified by compiler as function, which defined in corecrt_math.h In C, th...

13 dagen ago | 0

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I haven't defined syms x but solve function gives me values depend on x
The solutions are most naturally parameterized by e2, but you have specified that you want to solve for e2. So solve() has to in...

13 dagen ago | 1

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Answered
Create a 2D plot with irregular axes
pointsize = 20; scatter(x, y, pointsize, Dataset(:)) This will produce colored round dots at the given locations. Producing s...

13 dagen ago | 0

Answered
Question about sprintf not handling list{:} properly
X = ["a","b","c"] Y = [1, 2, 3] catinated = [X;Y] Look carefully at the output and notice that it is a string array. The nume...

14 dagen ago | 1

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Answered
Using fprintf in a for loop to display the output as a set of coordinate points
The basic problem is that fprintf() consumes all of each argument before going on to the next argument. Combine that with the fa...

14 dagen ago | 0

Answered
How to ensure Matrixes are matching size
K = zeros(4, 1,n); K is initialized to 4 x 1 by something. K(:,:,n)=P(:,:,n-1)*A.'*inv(A*P(:,:,n-1)*A.'+R); P is 4 x 4 b...

15 dagen ago | 0