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
Looping through object array, possible to get an iterator to index into the object array?
When you "for" name=array then matlab iterates over the columns of the array, setting the variable to each column in turn. So tm...

3 hours ago | 0

Answered
Why am I not getting output in the combinations of salts field?
You assign string into C and copy that to combination of salts, and then put that as the second entry in the cell. The cell gets...

12 hours ago | 0

Answered
how can i extract A= rand([3.85 9.22],5,1) without getting an error
rand(SIZE) * (UPPER - LOWER) + LOWER

12 hours ago | 0

Answered
Simplifying a symbolic expression
You are trying to find the symbolic roots of a degree 5 polynomial. It does not happen to be one of the quintic polynomials that...

15 hours ago | 0

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How can I change my username?
The first thing to do is run the Deactivation executable that you will find in your MATLAB installation directory. Then, change...

18 hours ago | 0

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Legend for multiple plots varying parameters
% matlab and maple for theta plot for different xi values figure subplot(2,1,1) hold on for ixi = 1:2 xi_part = "xi = "...

19 hours ago | 0

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Answered
Wcompress for 1D data
but i notice that the size of the data file after and before the wdencmp is the same, What you are writing to the file is the r...

20 hours ago | 0

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How to permute elements of jth column of a matrix iteratively
A=[1,2,3 ; 7,8,9 ; 13,14,15] perms_of_(A) function perms = perms_of_(A) [rows, cols] = size(A); perms = repmat(A, ...

20 hours ago | 0

Answered
Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.
Error in cell2mat (line 46) M(i,j) = C{i,j}; That line of code does not exist in Mathworks cell2mat, at least not ...

22 hours ago | 0

Answered
please help me for , create a plot of the two functions sin(1.5x) and cos(2x) from 0 to 4pi
y2=cosd(2x); There are absolutely *no* places in MATLAB that permit implicit multiplication. If you want to multiply two th...

1 day ago | 0

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Unwanted items showing up in plot legend
Record the handle of all scatter() calls in an array. Pass that array to legend()

1 day ago | 0

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Answered
Matlab code for solving nonlinear equations
In the general case that could be difficult and time consuming. For example the nonlinear system might be describing Elliptic Cu...

1 day ago | 0

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How to solve differential equation including derivative of eigenvalue of tensor?
You need to construct the formula for the eigenvalues of the derivative based on the equation for A. As you have a 3x3 matrix th...

1 day ago | 0

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Using regexp to parse plot's LineSpec
Shapes and colors in linespec may be given in full or in any leading prefix of the word, and the parts can be run together with ...

1 day ago | 0

Answered
load function: how do you to skip lines in ASCII File that generate errors?
No. load() of a text file is documented as only being guaranteed to work for files saved with save -ascii In practice load() ...

1 day ago | 0

Answered
Problem in evaluating the value of the derivative of multivariable function
matlabFunction(diff(f1, x), 'vars', [x, y] )

1 day ago | 0

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Answered
Symbolic Sum to find a general expression for arbitrary n terms and arbitrary variable definitions
You cannot do that in MATLAB for symbolic limits. For specific limit, n being a given positive integer, then you would not us...

1 day ago | 0

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initialize complex values in column vector
Suppose that you had coded [1 0 -1] then how many values would you expect as a result? Is that to be interpreted as ([(1...

1 day ago | 0

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why a message about license is show every time i run MATLAB"??
The message appears every time you start MATLAB because if it only appeared every second or third time you started MATLAB then y...

1 day ago | 0

Answered
abs function equivalent in c++
https://cplusplus.com/reference/cstdlib/abs/ In C++ abs() is overloaded and for double precision will call fabs() fabs() w...

1 day ago | 0

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How to use three differential equation in pplane in Matlab?
dfield is for one differential equation, pplane is for two differential equations, for studying phase planes. The software is...

2 days ago | 0

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replace diff function with for loop and if structures
Using if structures is pretty useless there. The calculation is very straight forward, and the only relevant questions are: do ...

2 days ago | 0

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Consider particle “P” having random walk in 1-D, Let N steps of equal length be taken along a line.
Encode a step to the left as binary 0. Encode a step to the right as binary 1. Any particular random walk of N steps can then be...

2 days ago | 0

Answered
How could i merge spectrograms ??
No, it is not possible to merge spectrogram(); see the technical discussion at https://www.mathworks.com/matlabcentral/answers/1...

2 days ago | 0

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Discarding certain values of a variable.
if (Hs<0.2) | (Hs>0.5) Hs=0; else Hs = [Hs 4*sqrt(sum(sum(s)))]; end In the first condition...

2 days ago | 1

Answered
Any comment to speed up the speed of caculation of symbolic loops having Legendre polynomials?
Wxy2(r) = W(i, j, 2, r)*legendreP(i, zeta__2)*legendreP(j, eta__2)*q(r, 1) + Wxy2(r); Wxy3(r) =...

2 days ago | 1

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Answered
How to store values in a matrix?
for theta = 0:5:90 R = [cos(theta) (-sin(theta)) 0; sin(theta) cos(theta) 0; 0 0 1]; end That is not creating one R f...

2 days ago | 0

Answered
Why do I get this error: "Could not evaluate MaskDisplay commands of block 'ADP_ControllerP00b/ADP_Controller/PIPD_FTC/PI_Fuzzy': getMaskDisplayString requires a Fuzzy" ?
status 0 for the test means that you do *not* have a valid license for the toolbox.

2 days ago | 0

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Can the symbolic toolbox be used to derive results for arbitrary number n?
syms n m symsum(m, m, 1, n)

3 days ago | 0

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Answered
Simulink library check l
2*pi appears to me to be a Constant block. The triangle at the S port of the Ideal Angular Velocity Source is part of the way t...

3 days ago | 0

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