# 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**

Why I am getting "Matrix is singular to working precision"?

The equations have an infinite number of solutions. They are consistent but the 4th equation can be deduced from the previous 3....

5 hours ago | 0

Matlab R2021a quit.

The code was attempting to use the third party package refprop version 9.0 or 8.1, which was for 2013 to 2016. The mex file used...

5 hours ago | 0

Unexpected behavior in classdefs that inherit from handle

This is documented. https://www.mathworks.com/help/matlab/matlab_oop/initialize-property-values.html#brqy3km-10 MATLAB evalua...

12 hours ago | 1

| accepted

Help me plot the solution in graph

A = randi([-9,9]) B = randi([-9,9]) C = randi([-9,9]) fun1 = @(x,y) A*x + B*y + C A2 = randi([-9,9]) B2 = randi([-9,9]) C2...

13 hours ago | 0

error when plotting 3 first order differential equations

syms x; You created x as a scalar symbolic variable. soln = ode45(@Problem03ODEFunction,[0 10],[0;0;0]); You calculate the so...

14 hours ago | 0

| accepted

Index exceeds the number of array elements (1).

format long g h = rand() %guess L = rand() * 3 %guess F = sort(rand(1,7)) %guess a = rand(size(F)) %guess b = ran...

16 hours ago | 0

processing a file but keeping blank lines intact

ConstantOffset = as appropriate; filename_in = 'as appropriate'; filename_out = 'as appropriate preferably not the same'; ...

16 hours ago | 0

How to keep the values for particular dimension of a matrix and rest of the dimension will be zeros?

Easy way: B = zeros(size(A), 'like', A); B(350:400,20:35) = A(350:400,20:35); Now B is A with all the other elements zeroed. ...

1 day ago | 0

I am confused on why I am getting huge numbers at the values 0,75,150, and 300 in my code

Algebraically, b should be 0 at 0, 150, 300 (but not 75), and division by 0 gives infinity. In the below plot, you do not see th...

1 day ago | 1

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How to prevent unwanted line breaks when using sgtitle function in figure?

pt_blk is a cell array so pt_blk(si) is a cell array. ['Pt: ', {'429-040 vs 041'}, ', Contact:'] Alternately, pt_blk might be...

1 day ago | 0

| accepted

Matlab creates same input values every time? Why?

Every time you load matlab, it does the equivalent of rng('default') which initializes the seed to 0. It is expected that the ...

1 day ago | 1

generate new coordinates (starting from initial coordinates) that are arranged outwards (by a distance H) and on the same plane

which are arranged outwards (by a distance H) I doubt that you want to arrange the points by distance H, but here it goes. lo...

1 day ago | 1

multiple colorbars in one figure

You can create multiple colorbar() using the 'Position' property. If colorbar() believes that a new colorbar overlaps an existin...

2 days ago | 2

Using an anonymous function handle as input into another function handle

Your premise is incorrect. The below example shows that it is valid to pass function handles between multiple levels omega = @(...

2 days ago | 0

use the 'patch' function with different results (using different matrices)

In your first patch() call you ask for 'k' -- black -- for the faces. The edge colors default to black as well. In the second p...

2 days ago | 0

How to test if equation in .p file is linear.

In some cases you might get lucky, in that if you pass purely symbolic variables to the function, you might get back a formula. ...

2 days ago | 1

Isosurface plots appear 2d when used with subplot

MATLAB has divides graphics calls into "high level" and "low level". "High level" calls check whether hold is on, and if not...

3 days ago | 1

Problems with savepath in R2023b

On a shared system, users should not have write access to pathdef.m inside the MATLAB installation directory. If this is not a ...

3 days ago | 1

I'm trying to make a for loop that has if statments that use the increments from my i to run them. How can I make this work, it won't run.

if i==0:99 The right-hand side of that == is a vector containing [0, 1, 2, 3, ... 99] The == is comparing the current valu...

3 days ago | 0

Using lsqnonlin and getting the message Error line 218.

clear all; clc; close all L=[3,3,3]; %starting point of electrode's position LEb=zeros(1,1); for xa...

3 days ago | 0

Algorithm 1. Set time step (increment) 2. set max number of time steps 3. start with ground values of temperature at x=0, y=0, z=0, theta=0, and a particular value of fi 4. co

Remember that comments extend to the end of the physical line, not to the next semi-colon, so your comment about "Initialize var...

3 days ago | 0

How do I use single precision numbers in a summation? My result is not coming out as expected.

You are not doing repeated addition. Repeated addition is not the same as multiplication. Also, a and b are scalar, so a*b is a...

3 days ago | 0

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I can not run my function file for zohplot

When you attempt to run a function by pressing the green Run button, MATLAB never, I repeat never searches the calling environme...

3 days ago | 0

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How to Find Duplicate Entries and give popup message in the 50 different Edit Field in MATLAB App Designer ?

[groupnum, group_content] = findgroups(app.YourGUITable.Data.Period); if numel(groupnum) == height(app.YourGUITTable.Data) ...

3 days ago | 0

Number of values stored are more than the ratio of stop Time/Step size ?

See https://www.mathworks.com/help/simulink/ug/choose-a-solver.html and https://www.mathworks.com/help/simulink/ug/managing-samp...

4 days ago | 1

Error 2, 753 when trying to activate key

First off: if you were installing the license server facilities, then the resulting MATLAB would not need to be activated -- bec...

4 days ago | 0

error to assign string in field struct's

Compare: Sis(73).Slipp = 'example'; [Sis.SlippSource] = testfun(); function output = testfun() output = 123; end

5 days ago | 1

| accepted

Licence manager changes / Activate and manage devices

Notice that the "Option" field is "Total HeadCount". The implication is that the license is not an individual license -- the "Ma...

5 days ago | 0

ascribe zeros to an array

frequencies = linspace(0, 2400, 250); spectrum = rand(size(frequencies)); subplot(2,1,1); plot(frequencies, spectrum); title...

5 days ago | 0

How can I resolve the error in output for a WSN simulation in MATLAB

endToEndDelay = endToEndDelay + (t - transmissionTimes(node)); You never reset endToEndDelay, so it becomes unclear...

5 days ago | 0

| accepted