Steven Lord

MathWorks

Last seen: Today | Active since 2002

Followers: 3 Following: 0

I joined The MathWorks in the Technical Support department during the summer of 2001 and transferred into the Quality Engineering department in March of 2004. I now work qualifying the core MATLAB numerical functions (PLUS, MINUS, LU, FFT, ODE45, etc.) Professional Interests: mathematics, MATLAB For assistance with MATLAB question please post to MATLAB Answers or contact Technical Support using the Contact Us link in the upper-right corner of the page instead of contacting me directly.

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after inter activation key write for me Invalid Activation Key (510). For help resolving this issue, see this MATLAB Answer.
If following the instructions in that MATLAB Answers post linked in the error message did not solve the problem, please contact ...

2 days ago | 0

Answered
Cannot define a cell array of custom classes in function argument validation
What's the default value for your property? properties (Access = private) configurations (1, :) cell {mustBeA(configurat...

3 days ago | 0

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I think, I might have a problem with the 'hold' part and I get the 'error while evaluating button privatebuttonpushedfcn'
Don't call figure if you don't want to create a new figure.

4 days ago | 1

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Can I use a struct in an anonymous function?
When I run the ode15s I obtain an error which pertains to the inclusion of the struct as an input to the function. Please show...

4 days ago | 0

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How to fill a variable with the results of an if...elseif statement
Rather than creating variables whose number of rows is not known ahead of time, I'd consider creating a table of coordinates and...

5 days ago | 0

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I am getting errors that I am using ".*" and "*" wrongly in my matrix multiplications in my code. I am poor at matrix algebra and don't know when to use each operator.
Read through this documentation page and ask yourself the question: do I want to multiple each element of one array by the corre...

5 days ago | 0

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Plotting a graph based on a large table
When you say "haven't got a clue how to do it" does that mean that you know what type of plot you want to create but don't know ...

6 days ago | 0

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Subtracting matrices by column and performing a summation.
Some functions you'll find useful are the diff, abs, and sum functions. The latter two are pretty easy to find in the doc by sea...

6 days ago | 0

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Choose any workspace from dbstack for evalin
It comes to me whether I can specify any workspace found in the dbstack here. No. For the evalin function in MATLAB you can spe...

6 days ago | 0

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splitting a vector into separate vectors
Can you dynamically create variables with numbered names like V1, V2, V3, etc.? Yes. Should you do this? The general consensus ...

6 days ago | 1

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Deployed Matlab function with strage errors: functions not found
I am fairly certain that the limitation described in the "Do Not Rely on Changing Directory or Path to Control the Execution of ...

6 days ago | 1

Answered
Using a variable in an input prompt
Another possibility you can use in recent releases of MATLAB (since I think release R2016a) is to use a string array. ii = 5; ...

8 days ago | 0

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Compare char data in a cell {'x'} to a character 'x'
You've got a lot in here. I'm going to step through certain parts. Let's start off with this comment (formatting added, your wo...

9 days ago | 0

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How do i multiply this matrix to work in MATLAB, it keeps sending an error
What did you expect to happen when you typed p. in your expression? That's not valid MATLAB syntax. If you had a number instead ...

9 days ago | 0

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Changing the value of only one parameter causes a problem (possibly with while loop)
Let's look at the while loop. while (V(i) >= Vmax) D(i)=floor(20*(sqrt(4*Q(i)/(pi*Vmin))))/20; V(i)=Q(i)/(pi...

10 days ago | 0

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Examples missing from requirements toolbox installation
I'm not 100% certain, but it looks like this page from the release R2022b documentation (the third entry under Topics in the Req...

11 days ago | 0

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Duration of time values for separate datasets and plotting on x-axis
set0_time=["085440","091530","092000","093020","100000","100020","101325"]; set0 = set0_time; set0_ydata=[30 50 60 72 82 85 88...

11 days ago | 0

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How can I bring back the command prompt in the command window after it disappeared ??? I cant execute commands !! if I press enter the commands disappear,
In the lower-left corner the status message says "Waiting for input". Does your code call the input function (perhaps with an em...

12 days ago | 0

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Answered
How to reopen tabs for different projects
Sounds like you may want to create a MATLAB Project for each of your projects.

12 days ago | 0

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Undefined function or variable 'aviread'. >> aviread('traffic.avi'); Undefined function or variable 'aviread'.
There used to be an aviread function in MATLAB, but I believe it was removed sometime around release R2014b. The recommended rep...

12 days ago | 1

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how i can show in matlab tha sqrt(x^2)=x in symbolic toolbox
That's not true in the general case. A = 1; h0 = 1; dhmax = 2; B = -5; lhs = ((2*A*dhmax + B*h0)^2/h0^2)^(1/2) rhs = (2*A*...

14 days ago | 1

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Answered
An absolutely ascending sequence
Those who have said there is no function for this are incorrect. The issorted function allows you to ask if an array is sorted a...

15 days ago | 4

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Strange case of Code analyzer and if-else block
It’s rather obvious that only one of the blocks will execute, and it seems redundant for the analyzer to flag this. In this cir...

15 days ago | 0

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The rotation in the rectangle function in matlab cannot be used, but the 2022 version can be used.
try rectangle('Position',[1 2 5 6],'Rotation',45); catch ME fprintf("This command threw the following error:\n%s", ME...

16 days ago | 0

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How can I fix ODE45 returning a straight line when using specific `tspan` points, instead of showing dynamic behavior over the time range?
Your ode_LR function is defined to accept four input arguments, the two required arguments plus two additional parameters. func...

16 days ago | 0

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error running getting started code
If you're using this matrix: a = [1 3 5 2 4 6 7 8 9]; the warning is correct. The matrix y...

16 days ago | 0

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Using "unique" to identify unique values AND number of occurrences of each unique value
Use the groupcounts function. A = {'AGAP001076-RD' 282 0.67229 'AGAP001076-RD' 285 0.75292 'AGAP001076-RD' 286 0.66957 'AGAP...

17 days ago | 0

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Having trouble printing variables I use as inputs to a function.
Let's look at a few selected lines of your code. The only variable that gets displayed with NaN values is uvwAndrSol so let's fo...

17 days ago | 0

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No matter the NOA matrix I enter, the result I receive is "empty double column vector" and I want to receive a numerical value.
Let's look at the last column of your two matrices. syms phi_a phi_o phi_n %Rotation in a T_a = [cosd(phi_a), -sind(phi_a), 0...

18 days ago | 0

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How to convert a function handle to symbolic function?
Are you hoping to use this fit object as the right-hand side of a differential equation ? If so keep in mind that fit objects ha...

19 days ago | 1