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Walter Roberson


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46.507 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
which kind of license can I use?
Standard individual license, also known as Professional license or Commercial licence (all are the same thing.) None of the o...

ongeveer 9 uur ago | 1

| accepted

Answered
32bit Compiler options
MATLAB Coder can generate C code that can be compiled by whatever toolchain you want. However MATLAB Coder supports very little ...

ongeveer 9 uur ago | 0

Answered
How can I compare two separate images (before and after) and count how many pixels are in a particular spectrum?
Example: RGB=imread('image.jpeg'); figure(1) imshow(RGB) HSV = rgb2hsv(RGB); H = HSV(:,:,1); R = RGB(:,:,1); G = RGB(:,:...

ongeveer 15 uur ago | 0

Answered
Trouble with struct indexing?
The best approach is not to do that. http://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be...

ongeveer 18 uur ago | 0

Answered
How to merge text files vertically?
projectdir = 'directory files are in'; outdir = 'directory files are to be written to'; %should not be same as projectdir ...

ongeveer 22 uur ago | 0

Answered
Normalized to unity by summation
You can use out= ((abs(c0)).^2) + symsum(c,n,1,inf); and that will be faster than for upper bound 100. The symsum() will stay ...

1 dag ago | 0

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Answered
How to import to Matlab many text files as table type
projectdir = 'directory the files are in'; dinfo = dir(fullfile(projectdir, '*.txt')); %use appropriate extension filenames ...

1 dag ago | 0

Answered
image processing canny edge detection
YourImage = imresize(imread('baby.jpg'), 1/8); R = YourImage(:,:,1); G = YourImage(:,:,2); B = YourImage(:,:,3); ER = ed...

1 dag ago | 1

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 ...

1 dag ago | 0

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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...

2 dagen ago | 1

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

3 dagen 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 ...

3 dagen ago | 0

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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

3 dagen 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...

3 dagen ago | 0

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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);

3 dagen 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), '...

3 dagen 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...

3 dagen ago | 0

| accepted

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 ...

3 dagen 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...

3 dagen 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

4 dagen ago | 0

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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...

4 dagen 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...

4 dagen 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

4 dagen ago | 1

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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...

4 dagen 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...

5 dagen 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...

5 dagen 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 ...

5 dagen 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...

5 dagen ago | 0

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

5 dagen 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).^...

5 dagen ago | 0

| accepted

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