# Walter Roberson

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.

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**Content Feed**

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...

ongeveer 8 uur ago | 0

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 ...

ongeveer 8 uur ago | 0

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() ...

ongeveer 9 uur ago | 0

Problem in evaluating the value of the derivative of multivariable function

matlabFunction(diff(f1, x), 'vars', [x, y] )

ongeveer 9 uur ago | 0

| accepted

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...

ongeveer 9 uur ago | 0

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...

ongeveer 9 uur ago | 0

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...

ongeveer 10 uur ago | 0

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...

ongeveer 14 uur ago | 0

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...

ongeveer 14 uur ago | 0

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 ...

ongeveer 20 uur ago | 0

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...

ongeveer 20 uur ago | 0

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...

ongeveer 21 uur ago | 0

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...

ongeveer 21 uur ago | 0

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) =...

ongeveer 22 uur ago | 1

| accepted

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...

ongeveer 23 uur ago | 0

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.

ongeveer 23 uur ago | 0

Can the symbolic toolbox be used to derive results for arbitrary number n?

syms n m symsum(m, m, 1, n)

1 dag ago | 0

| accepted

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...

1 dag ago | 0

Graph appears blank but the equation and code are correct.

The MATLAB / operator is "matrix right division". A/B is similar to A * pinv(B) (but not exactly that.) So when you have a row v...

1 dag ago | 1

| accepted

Vehicle speed calculation script

D = input('Enter distance vehicle travelled: '); T = input('Enter time required for the travel: '); vehicle_speed = D ./ T ...

1 dag ago | 0

How can I convert double from cell? (UAV LiDAR data workflow in forestry)

% remove duplicate points [uniqueZ,uniqueXY] = groupsummary(groundPoints(:,3),groundPoints(:,1:2), @mean); Your first paramete...

1 dag ago | 0

Solving Unknowns with Symbolic Toolbox

syms A B C D real eqn_1 = 3 == A + B; eqn_2 = 7 == C + D; eqn_3 = 4 == A + C; eqn_4 = 6 == B + D; eqns = [eqn_1 ...

1 dag ago | 0

How to become the author of simulink library？

If you would like to negotiate with Mathworks for Mathworks to include your work as an official part of Simulink, then you shoul...

1 dag ago | 0

Limit your question to one subject

You have if IoDL=="Increasing" & IoDR =="Decreasing" CP= "Maximum" elseif IoDL=="Decreasing" & IoDR =="Increasing" C...

1 dag ago | 0

Index in position 1 is invalid. Array indices must be positive integers or logical values.

Centroids are not generally integers. htextinsCent is not a function: it is an array that results from a call to insertText

2 dagen ago | 0

reading hdf5 file with dataset name containing special characters

If the command works in a console but not in a script, and you are using an old enough version of MATLAB (I see you are using R2...

2 dagen ago | 0

Join two table variables into one. == does not works of table type

You are doing () indexing on a table. The result would be a table row. You compare that to something else that is probably a tab...

2 dagen ago | 0

Custom creation function for GA

'CreationFcn', @(GenomeLength, FitnessFcn, options) myfun(GenomeLength, FitnessFcn, options, ExtraParameter)

3 dagen ago | 1

| accepted

I have a function but it doesn't generate any outputs, below is the function defined in the file. I though it might be that x1 is a call by value, but not sure

We do not know what your function SineTaylor is. We do not know what n is. It looks like the number of terms to use. Your if n...

3 dagen ago | 1

| accepted

How to convert hourly data into daily data for next 120 days

You had data for 120 days plus 1 hour -- 0, 1, 2, 3, 4, 5 is (5+1) = 6 hours not 5 hours. Your daily mean is constant because o...

3 dagen ago | 0

| accepted