Steven Lord

MathWorks

Last seen: Today | Active since 2002

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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Answered
How to solve: Limits must be a 2-element vector of increasing numeric values.
Let's look at a couple sections of your code. I'm going to comment out the function declaration line so I can run this in Answer...

32 minutes ago | 0

Answered
How to plot binned data from a table?
Take a look at the "Aggregate Timetable Data and Calculate Mean Values" example on the retime documentation page.

41 minutes ago | 0

Answered
Question about toolbox dependencies
The behavior you described for iqr is not a bug. The Version History on the documentation page for the iqr function in MATLAB f...

3 hours ago | 0

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Answered
Add suffix to name of all variables in workspace
Can you dynamically create variables with patterned names like a_test, b_test, c_test, etc.? Yes. Should you do this? The gener...

7 hours ago | 0

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Answered
How to round values of table with mixed types?
Using a sample table: Temp = [37.3;39.1;42.3]; Pressure = [30.1;30.03;29.9]; WindSpeed = [13.4;6.5;7.3]; WindDirection = cat...

7 hours ago | 0

Answered
What is an LAPACK loading error when using polyfit?
There are two Bug Reports that look potentially relevant to this situation. One was fixed in release R2014b and the other in rel...

7 hours ago | 0

Answered
How to create a datetime array in C++
The datetime function supports the Extended Capability of C/C++ Code Generation (with some limitations listed on its documentati...

7 hours ago | 0

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Answered
Time and Space Efficiency Problem in Multi-Format .csv file Splicing and Saving
Assuming your data files don't have any header rows, I'd consider avoiding the read/save process and just use operating system c...

1 day ago | 0

Answered
How to read the result of fprintf
ID = 42; fprintf('set %d\n', ID); When called with that syntax, fprintf does not write to a file. It writes to the Command Win...

2 days ago | 0

Answered
Inquiry about companies using Matlab for motor controller design of EVs powertrain
You could search the customer stories for stories about electric vehicles and motor control.

2 days ago | 0

Answered
numerical integration inf to inf
Look at your function over the region in question. e=0.01; f= @(x) 1./sqrt((1-x.^2)+(e/2)*(1-x.^4)); a=-1; b=1; fplot(f, [-...

3 days ago | 0

Answered
Viewing Symbolic Matrix Entries in Variable Tab?
If you're planning to use the symbolic expression in a loop you may want to create a MATLAB function file from it using matlabFu...

4 days ago | 1

Answered
Grey Wolf optimizer in matlab
The ability to define local functions in scripts was introduced in release R2016b.

4 days ago | 0

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Answered
App designer: How to define self-referring properties?
That code does not define a variable named x. It defines an object property named x. You're assuming that defining one property...

6 days ago | 1

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Answered
rng usability missing seed functionality
It looks like using "seeds" is being considered "old fashioned" in Matlab 2022b, and there is a warning about it suggesting it w...

6 days ago | 0

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Answered
How do I use matlab.uitest.TestCase to open my app once and perform multple function tests?
You could do this by opening your app in a TestClassSetup method and storing a handle to it in a property of your test class, bu...

7 days ago | 1

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Answered
How can I access the following builtin function code? [L,p] = chol(A,'lower')
We don't distribute the source code for the built-in chol function.

7 days ago | 0

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Answered
Trying to Increase efficiency by avoiding using If statements to select data
Can you dynamically create and access variables with numbered names like x1, x2, x3, etc. or similar names like L_Data and R_Dat...

7 days ago | 0

Answered
Is Home version an annual-basis or one-time purchase?
For your first question does the MATLAB Home product page (and the FAQ at the end of that page) provide you with sufficient info...

8 days ago | 0

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Answered
How to Convert symbolic variables to numeric
If it contains no symbolic variable use double. two = sym(2); sqrt2 = sqrt(two) x = double(sqrt2) If it does contain a symbo...

8 days ago | 0

Answered
Why in the Test Manager; option of select New > Test for C/C++ Code is not appearing?
According to the Release Notes the capability to perform C/C++ code testing in the Test Manager was introduced in release R2021a...

9 days ago | 0

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Answered
How to separate real and imaginary components from a given expression in Matlab?
syms X1 X2 XC RL Zin=((X1*XC)-1i*(X2*RL))/(RL+1i*(X1*X2*XC)); A=real(Zin) B=imag(Zin) What leads you to believe something ...

10 days ago | 1

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Answered
ODE solver not running full time span
That suggests to me that you should have received a warning but perhaps you've suppressed it? Something along the lines of "Fail...

10 days ago | 0

Answered
What are the differences between integral and trapz?
The integral function accepts a function handle as input and computes the integral of that function over an interval by evaluati...

11 days ago | 2

Answered
how do i solve this error: Undefined function 'imnoise' for input arguments of type 'uint8'.
The imnoise function is part of Image Processing Toolbox. Check the output of the ver function to determine if you have this too...

12 days ago | 0

Answered
I am learning still and i have no idea how to write 8y''' - y' = cos(20t) + sin(2t) in matlab
How are you trying to solve the ODE? Numerically or symbolically? If numerically, see the van der Pol example on this documenta...

12 days ago | 0

Answered
using linspace in a matrix incrementing by a certain number
There are several functions for creating regularly spaced vectors of given lengths depending on which three of the four paramete...

14 days ago | 0

Answered
Can we get functions from the curve fitting toolbox?
You can evaluate a fit as shown by the sections on this documentation page and this documentation page whose names start with "E...

14 days ago | 0

Answered
MATLAB switching between integer and floating numbers in a loop during computation
What you're missing is that 0.1 is not exactly one tenth. Welcome to the world of floating point arithmetic. See the "Avoiding C...

15 days ago | 0

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Answered
MATLAB 'copy command' has unrecognised function or variable
The command is correct. I just tried it and it opened the example as I expected. From the Release Notes for release R2022b, "Ma...

15 days ago | 0