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Walter Roberson


43 651 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
How do I measure the area of objects in a binary image, to be passed into the function bwareafilt?
regionprops() with the 'Area' option. However, there is another approach: bwareafilt(binimg, 2, 'smallest') If what you want ...

ungefär 14 timmar ago | 0

| accepted

Answered
Err0r within code
Your code for your function extendsignal() is clearly written for the case where the input is a row vector, but you are passing ...

ungefär 15 timmar ago | 0

Answered
Error using horzcat Dimensions of matrices being concatenated are not consistent.
temp_x is 500 x 231. num_padding is 250 in that code. In the expression y = [fliplr(y(2:2+num_padding-1)) y fliplr(y(e...

ungefär 15 timmar ago | 0

Answered
the runtime (computational complexity) of perms function?
You can look inside perms.m to see the private function permsr() -- which is iterative, not recursive like the comments imply. ...

ungefär 16 timmar ago | 0

Answered
How can I pass a parameter to nonlcon used with fmincon
http://www.mathworks.com/help/matlab/math/parameterizing-functions.html

ungefär 16 timmar ago | 0

Answered
Regular expression to match "="
regexp('a == b = d','(?<!=)=(?!=)') This looks for = that are not preceded by = and not followed by =

en dag ago | 2

| accepted

Answered
How to save variable in loop with different name?
http://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

en dag ago | 0

Answered
About sampling rate of a signal
You can just start using the data as if it were the higher sampling rate. However, by doing so you raise the frequency of the sa...

en dag ago | 0

| accepted

Answered
how to use fsolve with more equation
Bundle all of the variables into a single vector for the purposes of fsolve. You can unbundle them inside the function. vars20i...

en dag ago | 1

Answered
Excel import and operations
Probably the easiest way to do this is to use the symbolic toolbox. You can construct a struct in which the field name is the na...

en dag ago | 0

| accepted

Answered
TCPIP, Exaple function, check
You are missing a license for Instrument Control Toolbox. In some cases, especially with organizational machines, it is possib...

en dag ago | 0

Answered
How can I create multiple arrays, based on unique column values, from a single array?
G = findgroups(YourTable.ID); grouped_info = splitapply(@(speed, temp) {unique(id), speed, temp}, YourTable.id, YourTable.Speed...

en dag ago | 0

Answered
How do i resolve
parts is a function defined inside submitWithConfiguration See for example line 93 at https://github.com/tuanavu/coursera-stanf...

en dag ago | 0

Answered
Como interpreto los resultados de rootof?
>> solve(y5,'MaxDegree',4) ans = - ((270053049741483176957*((2^(1/2)*3^(1/2)*573897224629626001025423965510526852271292...

2 dagar ago | 0

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Answered
Writing a function that returns all the roots of any function within a certain range?
"Writing a function that returns all the roots of any function within a certain range?" That is known to be impossible in conti...

2 dagar ago | 0

Answered
Tab formatter is not working with sprintf
Fonts. As in the default is variable-spaced fonts. And tab does not have a particular width. tab is a concept for character-ori...

2 dagar ago | 0

Answered
Making my own operator
MATLAB does not permit you to create new operators. MATLAB does permit you to redefine many of the existing operators, such as ...

2 dagar ago | 0

Answered
2 integrals at once?
No, there is no special notation. What you pass as the first parameter to integral() must be the handle to a function that acc...

2 dagar ago | 0

Answered
Integration output is NaN
You have a sub-expression ./(neta.*rho.*P.*z) When z is 0, that is a division by 0. When you are working numerically and z is ...

2 dagar ago | 0

Answered
Error using eval when load many files in recursive
Don't use eval(). Construct your filenames using sprintf() and use the function form of load instead of the command form. http:...

3 dagar ago | 1

Answered
Index exceeds the number of array elements (1) error on line 10
if P3(i)>P2(i); Q3(i) = (P3(i)-P2(i))/R2; else Q3 = 0; end The else of that overwrites all of Q3 with a scala...

3 dagar ago | 0

| accepted

Answered
Disable windowkeypressfcn when specific child is on focus (app designer)
foo = uicontrol('style','slider', 'min', 0, 'max', 1); foo.Callback = @(hObject, event) fprintf('slider %g gco %g\n', double(hO...

3 dagar ago | 0

Answered
Sort Index - Bug
>> [a, sort_index]=sort([100;20;30;40]) a = 20 30 40 100 sort_index = 2 3 4 ...

3 dagar ago | 1

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Answered
imbinarize vs im2bw
label2rgb(label) is equivalent to label2rgb(label, 'jet') which triggers 'jet' to be executed with no parameters. When jet is ex...

3 dagar ago | 1

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Answered
How to update struct array fields with mutiple values
t = num2cell(1:10); [A.B] = t{:}; See comments for the case where the struct does not already exist.

3 dagar ago | 3

| accepted

Answered
append a text file to structure
fileread() is the easiest way. However if your file happens to contain utf8 characters I would want to double check whether f...

3 dagar ago | 0

Answered
How do I add row and column separators, and a border in a table so it looks like a real table?
You cannot do any of those things in r2019a. As of R2019b it is possible to use variable names that are not matlab identifier...

4 dagar ago | 0

Answered
Find minimum of an n variable function, n is like 800+
No. With 800 variables and non linear curv, it is unlikely that a global minimizer will find the global minimum. Especially so ...

4 dagar ago | 1

Answered
Is it possible to select an m-file for a "MATLAB function" block in Simulink?
No, you cannot load files into MATLAB Function Block. You can use the MATLAB Function Block as a very thin wrapper that just...

4 dagar ago | 0

Answered
How to show tf function to text box?
sys_char = evalc(sys); sys_cell = splitlines(sys_char); sys_cell = sys_cell(2:end-2); %some useless empty lines set(handles...

4 dagar ago | 0

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