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Walter Roberson


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46 499 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
Use Period Marker to fill circles drawn using viscircles
viscircles draws two lines with the same coordinates but with different line widths (and potentially different colors). This is ...

environ une heure ago | 0

Answered
easy question : why i get NaN here ?
J = 0.01; b = 0.0737; K = 0.072; R = 1.17; L = 0.024; syms w temp = K/(w*(((J*w+b)*(L*w+R))+K^2)); tempc = collect(temp...

environ 3 heures ago | 1

Answered
adding books to book list
fprintf(fid, '%s %s %s\n', NewCode, NewName, NewGenre) ;

environ 23 heures ago | 1

Answered
Error: The variable Calls in a parfor cannot be classified.
%% Place Call Times into corresponding variables CallA = Calls{1}; Earlier you index Calls{i} where i is the parfor ...

environ 23 heures ago | 0

| accepted

Answered
I kept on getting error that says "Error in port widths or dimensions. 'Output Port 1' of 'simulink_controller/Sum2' is a [2x2] matrix."
Pass the output of the Sum2 block through a Selector block https://www.mathworks.com/help/simulink/slref/selector.html

1 jour ago | 0

Answered
Is there a way to change the range function of xlsread based on a variable input?
var = input('enter excel column: ', 's'); variable1 = xlsread('filename.xlsx', sprintf('%s4:%s4', var, var)); variable2 = xlsr...

1 jour ago | 0

| accepted

Answered
How can i convert 160by1 column vector into 16by145 such that first column contain 1 to 16 and second column 2 to 17 and so on?
If you have the communications toolbox, then you can use temp = buffer(YourVector, 16, 15); out = temp(:,16:end);

1 jour ago | 0

Answered
Input Argument for contour must be real
rOD = real(OD_MO(:)); minOD = min(rOD); maxOD = max(rOD); contourf( X,Y, real( OD_MO), linspace( minOD, maxOD, 40), '...

1 jour ago | 0

Answered
how to use different columns of a passed matrix for individual time step in an ode
The ode*() routines are variable step solvers that will adjust their timestep as required to meet the integration tolerances. Th...

1 jour ago | 0

Answered
Help with "Dimension 1 is fixed on the left-hand side but varies on the right ([1 x 1] ~= [:? x 1])" error r2018a.
function plantOutput = modIndex(gridVoltage, setPoint) After that line add assert() statements that test that each of the ...

2 jours ago | 0

Answered
Evaluate definite integral numerically, where the function is indeterminate
Break the integration up into parts that are piecewise numerically integratable, and add the parts together. Do not, however, ex...

2 jours ago | 0

Answered
Passing a matrix as a parameter in ode15s
function dvdx = ode_x(x,vx,vfx) dvdx = reshape(vfx./reshape(vx, size(vfx)) - 1), [], 1); end

2 jours ago | 0

Answered
Is there a non-eval based solution to effectively getting the output of disp as a string value?
You can use diary() to have the output of disp copied to a file, then turn diary off and read the file. This will not be any bet...

2 jours ago | 0

Answered
JRE License for MATLAB Runtime
"As you know, Oracle doesn't allow JRE for commercial use without a license anymore." Not exactly correct. The restrictions a...

2 jours ago | 0

Answered
How to create a large matrix using another matrix
https://www.mathworks.com/help/matlab/ref/spdiags.html#mw_6de431d3-8887-4b16-b947-86a610ddea8c

2 jours ago | 1

Answered
ressistors with small random offset in SIMULINK
The attached model is adapted (solver parameters updated) from the File Exchange Contribution SERIES AND PARALLEL CIRCUITS, ver...

2 jours ago | 1

Answered
Triangle fitting using fminsearch
Guessing about what you were trying to do with that fT stuff: function FW = gaussplustriangle(x,x0,y,isPlot) %x0 is fixed cente...

3 jours ago | 0

Answered
Find Fundamental Frequency to know if it´s a Man or a woman or children
Your project is not possible to complete using any known science. Suppose for example that group A has a mean score on somethin...

3 jours ago | 1

Answered
Why are the results different when calculating a 10 x 3 matrix and a 1 x 3 matrix?
XYZ_rwd21t = [1.30937778204061e-14,-13.8617246105272,22.6275000000000; XYZ_rwt212t(i, 2) = XYZ_rwd21t(1, 2); Okay, so ...

3 jours ago | 1

Answered
fminsearch for ligistic fit
f2 = @(p)f(p,x); That relies on x existing in your workspace. If you are going to do that you might as well assume it on the...

4 jours ago | 0

Answered
Adding elements of a vector in matlab
fliplr( cumsum( fliplr(a) ) )

4 jours ago | 0

| accepted

Answered
Integration from 0 to a variable.
integral() is for numeric integration, but solve() is for symbolic work. fun2=@(x)((s-x).*((b/a).*((x/a).^(b-1)))/(1+((x/a).^...

4 jours ago | 0

| accepted

Answered
fprintf to plot error
See https://www.mathworks.com/matlabcentral/answers/534868-make-matrix-with-loop#answer_439778 for a general code outline that y...

4 jours ago | 0

Answered
Divide .wav file into equal segments
The below will split all .wav in a given directory into 3 second buffers. A directory named after the file will be created insid...

4 jours ago | 1

| accepted

Answered
How can I make a non uniform quantization of an image?
If you have the Communications toolbox you can use quantiz() https://www.mathworks.com/help/comm/ref/quantiz.html You can also...

4 jours ago | 0

| accepted

Answered
Matlab License for students
MATLAB Online is not free; you need to have an active account of one of several kinds. If Harvard has a Total Academic Headcoun...

5 jours ago | 0

Answered
Y axis in scientific form
If you are referring to the scale factor that sometimes get put up near the top of the Y axes, then the answer is that there is ...

5 jours ago | 0

Answered
solve vs. fsolve
Sometimes plotting and finding intervals by eye is not productive. In the general case, theory says that it is impossible to c...

5 jours ago | 0

Answered
Make matrix with loop
In the general case: xvals = [list of x values, does not have to be regularly spaced or even sorted]; numx = length(xvals); y...

5 jours ago | 0

Answered
Plot Not showing all values
The max value of col2 is only about 20, but the maximum value of col1 is 992008 Near 210 the entries go like 21.4239 21.5239 ...

5 jours ago | 0

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