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Walter Roberson

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

circa 3 ore ago | 1

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How to save variable in loop with different name?

circa 4 ore ago | 0

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...

circa 5 ore ago | 0

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...

circa 5 ore ago | 1

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...

circa 10 ore ago | 0

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

circa 11 ore ago | 0

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...

circa 11 ore ago | 0

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

circa 11 ore ago | 0

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

circa 14 ore ago | 0

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...

circa 14 ore ago | 0

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...

circa 15 ore ago | 0

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 ...

circa 16 ore ago | 0

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...

circa 16 ore ago | 0

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 ...

1 giorno ago | 0

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:...

1 giorno ago | 1

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...

1 giorno ago | 0

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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...

1 giorno ago | 0

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

1 giorno ago | 1

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

1 giorno ago | 1

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.

2 giorni ago | 3

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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...

2 giorni ago | 0

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...

3 giorni ago | 0

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 ...

3 giorni ago | 1

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...

3 giorni ago | 0

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...

3 giorni ago | 0

Is it possible to restore a deleted mat file?
Sorry, not through any method provided by Mathworks. Your operating system or third-party utilities might provide undelete meth...

3 giorni ago | 1

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is there any way to put two plots in one legend entry?
That happens automatically unless you do one of the following: call legend with a single legend entry, such as inside a loop or...

3 giorni ago | 1

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How do I remove leading characters from a string?
segments = regexp(dummy{1,1}{i,1}, '\t', 'split'); Perhaps you could have used readtable() on the ascii file: it would like...

3 giorni ago | 1

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Block Error, Singularity in Solution?
What I had to do to get your model to execute without error message, was to uncomment the saturation block that feeds the 1D loo...

3 giorni ago | 0