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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
Matlab error how to fix?
You cannot fix your code. It is not possible to create a uniform array in which the first column is datetime and the second colu...

4 hours ago | 0

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Answered
Fourier sine series plotting first term, first five term, and first 15 terms on one graph
x = 0:0.1:25; n = 1; ysin = fsin(x,n); plot(x,ysin) hold on n = 5; ysin = fsin(x,n); plot(x,ysin) hold on n = 15;...

21 hours ago | 1

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Answered
how to filter data by date?
FilteredDataRealizedVol = FilteredDataRealizedVol(FilteredDataRealizedVol{:,1} <= datetime(2016,7,18),:);

21 hours ago | 0

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Answered
Why am I getting the error "Too many output arguments"?
You do not initialize error before you use it. error happens to be the name of an important Mathworks function -- a function th...

1 day ago | 1

Answered
GA does not solve problems with integer and equality constraints
What you have to do is not declare [1 3 5 7] as being integer valued, and instead declare your own MutationFcn and CrossoverFcn ...

1 day ago | 0

Answered
Use of fmincon to minimise function with varying parameters, but receives 'Not enough input arguments'
[xOpt,fval,exitflag,output,lambda,grad,hessian] = fmincon(@(x) minCostFunction_b(x,parb),xInitial,[],[],[],[],xMin,xMax,@nonline...

1 day ago | 1

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Answered
How to simplify infinite double matrix summation in Matlab.
beta = 1.5; A = [1 0;0 2]; R = [0 3; 1 1]; syms k l t f = ((-A)^k./factorial(k)).*((factorial(k+l).*(-R)^l)/gamma((2-beta).*l....

1 day ago | 1

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Answered
length error don't know why
The error is not due to length(). The error is due to having run EDwithNetwork() without providing enough parameters In particu...

2 days ago | 1

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Answered
Tracking failed integral2() inside a for loop
Just before the integral2() call warning(''); Just after the integral2 call [msg, lastID] = lastwarn(); If msg is empty then...

2 days ago | 0

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Answered
How to convert radian to degree from answer (or equation) generated from syms
Q = @(v) sym(v); Pi = sym(pi); %% INPUTs: E = Q(2)*10^11; % Young's Modulus (in N/m/m) I = Q(3)*10^-3; % Moment of...

3 days ago | 0

Answered
How to recover corrupted *.mat file data
Unfortunately those files are not in .mat format and cannot be recovered. Both files start with the same sequence of 8 bytes, b...

3 days ago | 1

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Answered
Error using plot Vectors must be the same length.
t = (0:(N-1))/fs; s1 = sin(2*pi*10*t); s2 = sin(2*pi*20*t); s = [s1, s2]; s is a row vector that is twice as long as t (sin...

3 days ago | 0

Answered
Convert polar to cartisian coordinate
pol2cart uses radians. There is no Mathworks supplied Pol2Car function.

3 days ago | 0

Answered
Transparency in scatter plot
scatter(VectorOfX, VectorOfY, VectorOfPointSizes, VectorOfColor, ... 'MarkerFaceColor', 'flat', 'MarkerEdgeColor', 'flat', ...

4 days ago | 0

Answered
missing year in timetable
The range starts 01-Dec-2020 which is after 2020-01-01

4 days ago | 0

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Answered
Solution is not unique because the system is rank-deficient | Solve Function | Syms Variable | Will be very helpful, if you can resolve this pleaseeee
You are trying to solve three equations for one variable. Although two of the equations are inequalities, solve() simply gives u...

4 days ago | 0

Answered
Want to buy toolboxes for an older version of Matlab without renewing the license
Historically the rules were: purchasing against a previous release was permitted for a period, a period that was not clearly do...

4 days ago | 0

Answered
Please help me with syntax error on line 52
% Example inputs before calling the function ne = 10; nn = 2*ne + 1; mesh.x = linspace(0, 6, nn); mesh.conn = [1:2:nn-2; 2...

4 days ago | 0

Answered
str2double with long string seems to give wrong answer
format long g str = '6879331413876961408'; num = sscanf(str, '%ld')

4 days ago | 1

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Answered
What is the requirement of opinionScores for fitbrisque?
It looks to me as if that should only happen if imds is empty.

5 days ago | 0

Answered
Find out θ in the cos(wt+θ) = A
eqn2 = solve(eqn2, theta, 'returnconditions', true); will probably return a solution that is parameterized in terms of an extra...

5 days ago | 0

Answered
I am trying to perform the second derivative test of this function I came up with
Q = @(v) sym(v); Pi = Q(pi); E = Q(9.9)*10^6; p = Q(.098); F = Q(1500); L = Q(20); g = Q(32.2)*12; I = (F*L^2)/(E*Pi^...

5 days ago | 0

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Answered
The problem with calculating multidimensional integrals
Each layer of integral() that you call passes in a variable-length vector of values. trigl_funcs = @(e) cos( integral(@(zz_...

5 days ago | 0

Answered
Verify the File Path Check File Existence Verify File Permissions Check File Identifier Error Handling for File Openingwith thermo dta to matlab
[f1, msg] = fopen(file_path, 'r'); % Check if file opening was successful if f1 == -1 error('Cou...

5 days ago | 0

Answered
Multiple plots - change x axes all at once once
set(HANDLES_TO_CHANGE, {'XData'}, repmat({NEW_X_VALUES}, size(HANDLES_TO_CHANGE,1), 1));

5 days ago | 0

Answered
How to extract a matrix of values from cell array of cell arrays of structs
msea = zeros(n1,n2); for i=1:n1 msea(i,1:n2) = [mse{i}{1:n2}.metric]; end

5 days ago | 0

Answered
Getting unwanted box in the legend
The boxes in the legend are because you are using surf() You could create dummy lines, H(1) = plot(nan, nan, 'LineStyle', '--'...

5 days ago | 0

Answered
How can you determine the mean and standard deviation on a polar histogram?
You have to do something like norm_angle = Angles; mask = norm_angle > 180; norm_angle(mask) = norm_angle(mask) - 360; mean_...

6 days ago | 0

Answered
Solving and plotting equation with many variables
The solution of solve(eqn, x) is in four parts, with different conditions for each part -- conditions depending on the values of...

6 days ago | 0

Answered
Enforcing values in ODE solver
Use events, and remember that events are only detected when a value crosses the trigger, and are not detected when the system st...

6 days ago | 0

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