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
Will Dropbox new use of Apple file API make things difficult for me?
MATLAB's uigetfile() already uses native operating system file choosers, so if you have been using uigetfile() on MacOS you alre...

ungefär 2 timmar ago | 0

Answered
error on line 42 : gui_mainfcn(gui_State, varargin{:});
Change delete(instrfind({'Port'},{'COM3'})) clear a; global a; a = arduino(); to global a; if ~isempty(a); clear global a...

ungefär 7 timmar ago | 0

Answered
Code not showing any result or any error
Your code defines kepler_plot but never invokes it. But you have other problems as well. I had to guess what you were doing. e...

ungefär 11 timmar ago | 0

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Requesting a demo code for calculating second-order statistics (contrast, correlation, energy, homogeneity, and entropy) for medical images.
Split the code up into two parts: read the medical images into memory arrays code that calculates second-order statistics on m...

ungefär 16 timmar ago | 0

Answered
Concatenating matrices unable to create a row jump
cruzzi = []; Numeric array. cruzzi{i} = [cruzzi imbinarize(tigger{i,o}, carrey)]; First cycle, cruzzi is the empty nu...

ungefär 16 timmar ago | 0

Answered
Parameter tunning using GA
You cannot fix that. You are calculating four costs each time, but ga() can only handle one cost at a time. ga() will never be a...

ungefär 16 timmar ago | 0

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Answered
how to solve this, Error using .* Arrays have incompatible sizes for this operation. Error in Elm (line 156) tempH_test=InputWeight.*TV.P;
The .* (element-by-element multiplication) operator can proceed in the case where: every dimension that is not 1 in either Inpu...

ungefär 16 timmar ago | 0

Answered
How to use subroutines inside subroutins in GUI functions?
A different one of your questions implies that you are using GUIDE, or hand-building your code -- that in particular you are not...

ungefär 17 timmar ago | 0

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Is it possible to pass a variable throu a callback function?
Yes. In general see http://www.mathworks.com/help/matlab/math/parameterizing-functions.html However, in the special case of set...

ungefär 18 timmar ago | 1

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Answered
How to write a subfunction inside a GUI function?
Yes, it is possible. In the case of App Designer you might have to define the function in a separate .m file if it is not a cal...

ungefär 18 timmar ago | 0

Answered
How to create a protected file
Not really. You can embed a SoC kind of computer within a tamper-resistant covering that would be likely to break with all of...

ungefär 22 timmar ago | 0

Answered
Universal Time to Local Time conversion
If LT is datetime() then you need to adjust the Format property of LT I recently encountered someone who was doing a similar ...

ungefär 23 timmar ago | 0

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Answered
Process .dat file, plot, scale, and put back into similar format
Your code says to scan the file for 8 floating point numbers with commas between them with a delimiter of tab. But your file con...

en dag ago | 0

Answered
this code was sabotaged please correct it
The missing code for unified_friction_pipe is on page 100 of Managed Pressure Cementing Simulations of Pressure and Flow Dyna...

en dag ago | 0

Answered
怎么用matab找到对某个概率密度函数从0开始积分对应积分结果为0.5的积分上限，
format long g f = @(x) exp(x).^2 - sin(x); %example function x0 = 0.8; UB = fsolve(@(ub) integral(f, 0, ub) - 0.5, x0) ...

en dag ago | 0

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Answered
Index exceeds array dimensions. Index value 9 exceeds valid range [1-1] for array 'm2'.
m2((l1^2) MATLAB has no implied multiplication. That is a request to index m2

en dag ago | 1

Answered
Error in data size using CIC filter in Simulink R2020b: The number of input rows must be a multiple of the decimation factor
You appear to be passing a 1 x 1 signal into decimation. Decimation works on a non-scalar. You probably need to buffer the sig...

2 dagar ago | 0

Answered
How can I get the right image ratio when displaying an image behind a graph?
The rule is that the XData you provide will be used as the center of the pixels. You want to shift the boundaries by half of a p...

2 dagar ago | 0

Answered
I am coding a kinetic equation by using ode dsolve but i got: Warning: Unable to find symbolic solution.
Your O3 is a function of t. You have O3^m where m is an unknown. You are not going to find a solver that is able to deal with ...

2 dagar ago | 0

Answered
I have a problem with the angle function
Your angle(Ew) oscillates around 0 so quickly that unwrap() ends up just adding more and more full cycles to try to keep up. Eve...

2 dagar ago | 1

Answered
How can I load a field from a struct that is stored within a .mat file?
In the case that the .mat file was saved with -v7.3 then see https://www.mathworks.com/help/matlab/import_export/load-parts-of-v...

2 dagar ago | 1

Answered
three order complex coefficient polynomial root matlab
syms x A B C eqn = 28*x^3 + A*x^2 + B*x - C == 0; solutions = solve(eqn, x, 'MaxDegree', 3) char(solutions(1)) char(solution...

2 dagar ago | 0

Answered
How to solve the problem of finding several similar names?
pat = digitboundary + filename + digitboundary; [row,column]=find(contains(filenamenew, pat)); This constrains the search to c...

2 dagar ago | 0

Answered
why do Simulink signals end up with different lengths after simulation?
Generally speaking, conditional execution can result in signals being inactive during all or part of the execution; those are no...

2 dagar ago | 0

Answered
How to use parallel.pool.Constant to save on overheard for large array constant across all calls to parfeval?
Version history R2023a: Constant objects no longer automatically transferred to workers MATLAB will no longer automati...

2 dagar ago | 0

Answered
Reloading handle objects from .mat files
f1 = figure(1); ax1 = axes('Parent', f1); h1 = plot(ax1, 1:10); save tst f1 h1.YData(end) = 5 datastruct = load('tst'); ...

2 dagar ago | 1

Answered
When I run my code, I keep getting this error: "Undefined function or variable 'y'."
Later you keep referring to sol.y so perhaps the reference to y should instead be to sol.y

2 dagar ago | 1

Answered
I have xyz data from which i want to formulate an equation
No, it can be shown mathematically (and I have posted proofs before) that given any finite set of finitely-represented points, t...

2 dagar ago | 0

Answered
What am I doing wrong here? I Keep getting "All table variables must have the same number of rows." error.
methodNames = {'GLLS', 'fminsearch'}; That is a row vector of length 2 standardErrors = [S_t_eq1_glls, S_t_eq1_fmin, S_t_eq2_g...

3 dagar ago | 1

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Answered
Linearization using the power function
x = 0:0.2:1.8; y = [1.3 2.1 3.0 5.2 8.4 13.5 22 33.5 53 85.4]; x starts with zero xx = log10(x); log10(0) is You cannot ...

3 dagar ago | 0

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