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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. I am currently caught up to T0099119; if you are waiting on a reply from me for an older issue, please send me a reminder.

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

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Answered
I want to find use regioprops and find the centroid of this shape along with other properties such as area of this shape. any ideas?
filename = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/1094395/image.jpeg'; img = imread(filename); bw = i...

12 hours ago | 1

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Answered
Using function handles in a ODE function
Your Y1, Y2, Y3 are numeric. Your dY3dt is a function handle. You try to put those all together in one array. Your function ne...

12 hours ago | 0

Answered
APP not starting - Unrecognized property 'BackgroundColor' for class 'matlab.ui.container.GridLayout'.
You need R2020b or later to use that .p file.

13 hours ago | 1

Answered
What is LBL file format and is it possible to open it in MATLAB?
[Copying from comment] The LBL (label) file contains fields that give explicit field number (column number) and field name...

14 hours ago | 0

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Answered
What is the differences between Annual and Perpetual licenses
Perpetual Non-Student: You can use that version of the software for as long as your organization exists (and you continue to ru...

14 hours ago | 1

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Answered
How to do vehicular simulation in Matlab?
See https://www.mathworks.com/products/automated-driving.html and https://www.mathworks.com/videos/matlab-and-simulink-racing-...

14 hours ago | 0

Answered
how to append data in hdf5 file.
hdf5write('check_v1.h5','/g1/coordinates',all_data); hdf5write('check_v1.h5','/g2/coordinates_vel',all_data1, 'WriteMode', 'app...

15 hours ago | 0

Answered
Saving a table-type variable to MAT file column by column in For-loop
outdir = pwd(); var = [num2cell(rand(4,3)), {'Steve';'John';'Paul';'Evan'}]; A = splitvars(table(var)); A.Properties.Variab...

15 hours ago | 0

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Answered
Why is my histogram only displaying 3 bins? And why is the xlabel not printing?
You ask for BinWidth 0.01 . Perhaps your data spans less than 0.03 so only 3 bins are justified. xlabel('$Q_\mathrm{ice} \mathr...

15 hours ago | 0

Answered
Customizing the axis on a plot - Mainly the tick marks
ax = gca; xticks(ax, 0:100:600); xlim(ax, [0 600]) ax.XMinorTick = 'on'; yticks(0:10:40); ylim([0 40]) ax.YMinorTick = 'on...

16 hours ago | 0

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Answered
Editing structure fields using a MATLAB App
assignin() can only assign to complete un-indexed variables. You will need to load the current struct into your workspace, modi...

17 hours ago | 0

Answered
Integrate a polyfit-polyval in matlab, I would appreciate any input. I want to calculate the integral of the sine function from a trend li
https://www.mathworks.com/help/matlab/ref/polyint.html polyint() the component vector to get the integral of the polynomial, ...

21 hours ago | 0

Answered
error in ode45 command
You could experiment with ode23s but it will probably lead to the same result. You have a singularity in your equations when ...

21 hours ago | 0

Answered
I am trying to print a structure array
structfun(@(F) mat2str(F), lambda3, 'uniform', 0)

23 hours ago | 0

Answered
Average images as they are captured
read first image. This establishes size of images. set imgtot to double(img) and count to 1 loop reading images. At each poin...

1 day ago | 0

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Answered
Specify initial condition for linprog?
https://www.mathworks.com/help/optim/ug/linprog.html#buusznx-options Use the options to set the Algorithm to interior-point

1 day ago | 1

Answered
How to change the font size of xtick and ytick with scientific notation on the side?
Scientific notation is always disabled when you supply your own tick labels. Scientific notation is only for automatic labeling....

1 day ago | 0

Answered
grabbing specific/not all files in a folder
Unfortunately the wildcards that MATLAB accepts are only a subset of what is generally supported by the operating system. You wi...

1 day ago | 0

Answered
Plotting a mxn Matrix
What you show is okay. As you are using imagesc() you might want to pass in an 'AlphaData' option with a double precision matri...

1 day ago | 1

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Answered
number of cpu cores used in matlab
https://www.mathworks.com/help/matlab/ref/maxnumcompthreads.html from the command line. But if you are wanting to do this fo...

1 day ago | 0

Answered
How to reduce the usage of "broadcast variables" when using parfor
"Is there a way to avoid this "unnecessary communication overhead", so that this parfor loop can run faster please?" No. You ...

1 day ago | 0

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Answered
Question about the fminsearch Algorithm
"So, first I wanted to know if my thoughts are correct?" Yes. "Intuitively I would say that it would be more effective if ...

1 day ago | 0

Answered
Writing to .mat simultaneously with parfor loop
This is a valid concern. save() does not promise to be thread-safe If I recall correctly, a few weeks ago there was a post fr...

1 day ago | 1

Answered
I'm trying to save a sequence of images generated in MATLAB individually
"Firstly, is there a different way to save them individually, despite the fact they're in a cell?" No. Some of the image writ...

1 day ago | 0

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Answered
How to increase the resolution of a list of images
You have a series of images that all happen to be bright in certain areas. Because they are all bright there, the variance betwe...

1 day ago | 0

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Answered
Can I share my standalone desktop application to be used freely by end product users?
No, with the Academic license, you can share the executable "for internal purposes" within your organization, or with your resea...

1 day ago | 1

Answered
how to load multiple files from directory into an array using matlab?
dinfo = dir('*.mat'); filenames = {dinfo.name}; for K = 1 : length(filenames) temp = load(filenames{i}); FN = fieldn...

2 days ago | 0

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Answered
HOW TO XOR NEGETIVE DECIMAL NUMBER?
for i=1:16 S = dec2bin(typecast(double(smod(i)), 'uint8'), 8) - '0'); F = dec2bin(typecast(double(finalkey(i)), 'uint8...

2 days ago | 0

Answered
Unable to find explicit solution
That equation is much too complex to hope for a closed form solution. You will not be able to find a symbolic solution. For a...

2 days ago | 0

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Answered
Please How I can use meshgrid with x and y are the elements of the matrix A and plot a figure like in the picture
This does not look like a contour plot at first, but notice the upper right corner. syms P Q D = det([P, 2; 0, Q]); x = linsp...

2 days ago | 0

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