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Walter Roberson


41.379 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
I cant able to run power_PVarray_grid_det command in matlab R2018b command window
It is not part of MATLAB itself. It is at https://www.mathworks.com/matlabcentral/fileexchange/52434-power_pvarray_grid_det Yo...

ongeveer 5 uur ago | 0

Answered
Error : Objective function is returning undefined values at initial point. lsqcurvefit cannot continue
You have a couple of issues: The last entry of your second column of your file is empty, so you are getting NaN values. This is...

ongeveer 5 uur ago | 0

Answered
saving a .csv file with text values as a .mat file
T = readtable('fisheriris.csv'); Tlabcat = categorical(T{:,5}); Tcats = categories(Tlabcat); Tlabnum = double(Tlabcat); Tnum...

ongeveer 6 uur ago | 1

| accepted

Answered
Is it possible to use the function IRFunctionCurve with a Matlab version R2018a?
That function continues to be present in the Financial Instruments Toolbox as of the latest available release. https://www.math...

ongeveer 6 uur ago | 0

Answered
Extract multiple images from a single image
C = mat2cell(YourBigImage(1:3052, 7476,:), 218*ones(1,4), 178*ones(1,42), 3); Now C will be a 4 * 42 cell array, each entry of ...

ongeveer 6 uur ago | 0

Answered
Do I own the copyright of the AppDesign/GUI that I have developed? And Can I use CC (Creative Common) Sign in the app interface?
Mathworks does not make any copyright claim for anything you have written. Copyright usually resides with the person who wrote ...

ongeveer 9 uur ago | 2

| accepted

Answered
How "hold on" function works?
After you hold on you can do ax = gca; set(ax, 'XLimMode', 'auto', 'YLimMode', 'auto') before you draw the new items. No...

ongeveer 10 uur ago | 1

Answered
Insert rows from one matrix into another that share the same column numbers?
[found, idx] = ismember(N(:,2:4), M(:,2:4), 'rows'); M(idx(found), 5) = N(found,5); However the code in this form will not wor...

ongeveer 10 uur ago | 0

| accepted

Answered
greater than less than
voltsadd_val = volts_add >= 0; No logical indexing required.

ongeveer 11 uur ago | 0

Answered
How to write function to find minimum of function with two variables?
fmincon(), fminunc() -- search for local minima fminsearch() -- also a local minimizer but one that is a bit better at not gett...

ongeveer 11 uur ago | 0

Answered
Error using erf. Input must be real and full.
for ii=1:length(t) f4 = ((exp(-i*w*t(ii))*conj(C_A)+exp(i*w*t(ii))*C_A)/(2*pi)); C_I(ii) = C_I0 * double( vpai...

ongeveer 11 uur ago | 0

Answered
Read in timestamps from weird time format
If the data is stored in a cell array of character vectors, S, then datetime(S, 'InputFormat', 'uuuu-MM-dd''T''hh:mm:ss''Z''', ...

ongeveer 11 uur ago | 0

| accepted

Answered
calling function return only one iteration answer
You are passing in 6 inputs to a function that expects 5. Current versions of MATLAB (as far back as I can recall) would refuse ...

ongeveer 11 uur ago | 0

| accepted

Answered
comparing and updating fields in a structure
If you have an SSID and you want to find out where in a list of SSIDs that the given one occurs, then you can [wasfound, idx] =...

ongeveer 11 uur ago | 0

Answered
MINIMIZE symbolic function P
syms t t0 tf N = 6; M = 2; x = sym('x',[6 M]); X(t) = str2sym(string(x) + "(t)"); a = diff(X(t), t); b = a'; f = b*a; f_...

1 dag ago | 0

Answered
How to remove this error, I get it in all my programme?
Use which -all gradient I suspect you will find that you have your own gradient.m or else that you have a third-party toolbox ...

1 dag ago | 0

Answered
Porting over some code to Python and I don't understand this multiplication syntax
It is not anything special. In order for [d;1] to work, d and 1 would have to have the same number of columns. Since 1 has one...

1 dag ago | 1

Answered
y position of a rectangle drawn over an image compared to axes
Depending on the state of the axes (hold on or not) and the image drawing function you use, it is common for the image drawing f...

1 dag ago | 0

| accepted

Answered
Double vs Single Precision, Matlab in 2019
>> x = linspace(single(0),single(pi),20); >> y = single(rand(1,20)); >> z = interp1(x, y, linspace(single(0),single(1),20)) z...

1 dag ago | 0

Answered
Is there any way to separate the terms of a product?
If you have the Symbolic Toolbox, then f = @(x) exp(x-2)*log(x) syms x temp = f(x); op0 = feval(symengine, 'op', temp, 0) r...

1 dag ago | 0

| accepted

Answered
How to install and enable Symbolic Math Toolbox
https://www.mathworks.com/matlabcentral/answers/101885-how-do-i-install-additional-toolboxes-into-an-existing-installation-of-ma...

1 dag ago | 0

Answered
How do I install additional toolboxes into an existing installation of MATLAB?
In sufficiently new versions of MATLAB, there is an additional installation method for Mathworks toolboxes that you have already...

1 dag ago | 1

Answered
Outputting solutions to symbolic variables in a matrix.
It sounds like Matrix is now an array of symbolic expressions, some probably representing just numbers, and some probably repres...

1 dag ago | 0

Answered
Command window showing the errror 'Index exceeds matrix dimensions'. How to resolve it? Following is my code if possible resolve the code.
Somehow you accidentally assigned a value to a variable named imageInputLayer, so the line of code now refers to the variable, i...

1 dag ago | 0

Answered
Plotting trajectory of ball
sin() expects radians.

2 dagen ago | 0

Answered
Newtons Method, help calling anon function inside of function file
You are calling the anonymous function properly in your code. Your problem is that you are not passing in an anonymous function...

2 dagen ago | 1

Answered
Eigenvalue With a twist...
bwep = solve(beep, x) This can be somewhat slow by 4 x 4 A, and by 5 x 5 it might just give you a bunch of roots() because of t...

2 dagen ago | 0

Answered
converting vector to 3d array
rgb2gray(reshape(TheVector, 32, 32, 3)) for any one vector of length 3072 (1024 x 1024 x 3). The result would be 2D, 32 x 32 . ...

2 dagen ago | 0

Answered
How to run optmization on vectors?
That particular error message has several possible causes: You have accidentally called your own MATLAB script fminsearch which...

2 dagen ago | 1

Answered
What will happen if you bought a MATLAB Student license after you graduated university?
MATLAB Student licenses never expire. However, you only have permission to use a Student license while you are enrolled in an ap...

2 dagen ago | 2

| accepted

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