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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 T0099089; 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
How to make imshow function faster in the for loop?
To make imshow() faster... Don't call imshow() Seriously: imshow() has a lot of overhead. Instead, call image() once and reco...

13 hours ago | 0

Answered
Unable to convert expression into double array, in Gamultiobj
Use matlabFunction() to convert yy to a numeric function. Be sure to use the 'vars' option to bundle all of the inputs into a si...

13 hours ago | 0

Answered
Optimization problem with lower and upper bounded constraints
clc; clear x = optimvar('x',10,'UpperBound',[2000;16000;120;5000;2000;93;95;12;4;162],"LowerBound",[0;0;0;0;0;85;90;3;0.01;145]...

14 hours ago | 0

| accepted

Answered
Conditional addition of matrix rows?
https://www.mathworks.com/help/matlab/ref/movsum.html#namevaluepairarguments movsum() with 'Endpoints', 'shrink'

15 hours ago | 0

Answered
diff function can not be used for a timeseries variable ver 2019b
That code is not expecting a timeseries object to be passed in: it is expecting a vector of times as the first parameter, and a ...

16 hours ago | 0

Answered
Genetic Algorithm functions unrecognized
After line 201 nueva2=nueva1; there should be an end statement before the next line function [nueva]= selection(poblaci...

16 hours ago | 0

Answered
Numeric column not read as string with readtable on XLS file
Excel stores "general numbers" in .xls files as binary floating point ("XNUM"), not as text. You can open the spreadsheet and ...

16 hours ago | 0

Answered
I am trying to create a while loop to solve this problem (step-by-step) until it meets the criteria stated. I need help in checking if my code is written clearly. Thanks
Unfortunately, someone who was not familiar with the field would have little idea what is going on. What is K -- is that spring ...

18 hours ago | 0

Answered
Storing small numbers and logarithms.
Depending on your range of values and your accuracy needs, you could try a double taylor approximation. syms a b positive E = ...

1 day ago | 1

Answered
Insert blank cells in a matrix
You cannot do that. Numeric matrices cannot have spaces in them. You can convert the matrix into a cell array and put spaces in...

1 day ago | 0

Answered
How to read image one by one from folder and make prediction save it in CSV format
net = load('11ClassesResnet.mat') net=net.trainednet inputSize = net.Layers(1).InputSize; path_directory='C...

1 day ago | 0

Answered
How to display "serial device connected" or "not connected"?
serialportlist('available') can tell you whether the port of interest is "available" serialport() objects appear to try to open...

1 day ago | 0

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Answered
Question regarding arranging matrix values
circshift()

1 day ago | 0

Answered
Unspecified behaviour of function imag.
This will not affect your code. You are encountering Command/Function Duality https://www.mathworks.com/help/matlab/matlab_prog...

1 day ago | 0

| accepted

Answered
How to solve this error when I use fmincon?
if (M(end) >= (Trigger * N)) && ~alreadyCalled % triggering level % Calling for the very first time if we ...

1 day ago | 0

| accepted

Answered
why The name 'Parent' is not an accessible property for an instance of class 'matlab.graphics.GraphicsPlaceholder'?
Put a breakpoint in at the begining of the sequence of statements where h() is assigned to, the series h(1) = surface(x,y,z,'Fa...

1 day ago | 0

Answered
Variable change should not affect during loop execution?
Function for variable = 1 : number_of_iterations original_a = a; original_b = b; if (condition) ...

1 day ago | 0

Answered
Pcolor Plot for 50,000 values
https://www.mathworks.com/matlabcentral/fileexchange/38856-quiver-plot-for-scattered-data

1 day ago | 0

Answered
How do I prevent resuming after a callback function interruption?
To prevent the previous computation from resuming, you have two choices: Force infinite recursion so that you get an error for...

1 day ago | 0

| accepted

Answered
1 - 1 = -0 on Matlab why? How to fix that?
num2hex(x(1,1:2)) You will find that they have slightly different internal representations.

1 day ago | 0

Answered
error [empty sym] using dsolve "Warning: unable to find symbolic solution"
conds = [cond_T_ad; cond_T_de; cond_T_co; cond_T_ev; cond_q_ad; cond_q_de; cond_M_w_co; cond_M_w_ev] Those are all equations i...

1 day ago | 0

Answered
How do I close the udpport with 2021b? Error Unable to bind to LOCALHOST and LOCALPORT. Verify that the LOCALPORT is not in use...
in theory it needs to have the variable holding the port cleared. I suggest that you put in an onCleanup to ensure that it is do...

1 day ago | 0

Answered
Solving Nonlinear Matrix Equation
fun1=matlabFunction(sum(L1)); That is going to produce a function with two inputs, mu1 and mu2. fsolve() only provides one ...

1 day ago | 0

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Answered
If I update matlab selecting only MATLAB and a toolbox that I'm interersted into, Will I keep the toolboxes I downloaded earlier?
If you purchase a new matlab license then it will *not* have access to other toolboxes. Toolboxes are associated with a license,...

2 days ago | 1

Answered
Can I use the symbolic math tool box to solve a series of expressions symbolically with respect to specific terms?
You must solve() for as many variables as the rank of the system. You have 12 equations in 11 variables. There might not be a...

2 days ago | 0

Answered
nested function calculation problem
Your functions do not return values. You cannot add them.

2 days ago | 0

Answered
I want to find the definition from the library that the result corresponds to
For the question you asked: Use ismember() to search for an exact match. For the question that you did not ask: sum(sco...

2 days ago | 0

Answered
Add randomness to DTFT Touch tone generation
If you already have the non-noisy signal then https://www.mathworks.com/help/comm/ref/awgn.html awgn()

2 days ago | 0

Answered
How to format my code in this way? Is there any shortcut?
If you are asking whether there is a keyboard shortcut for starting one of these "Code Example" blocks, then unfortunately the a...

2 days ago | 0

Answered
I am trying to change specific values of a matrix with a new ones.
Choose one approach: * take interest rate plus one, to the power of the number of periods, and multiply by the initial value ...

2 days ago | 0

| accepted

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