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Steven Lord


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MathWorks

5,065 total contributions 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
Finding the trajectory of a ball
Do not call ode45 with fball as the ODE function from within fball itself! That way lies (at best) a recursion error. Call ode45...

15 hours ago | 0

Answered
What value is 1.0000e-03 in normal numbers?
format longg x = 1.0000e-03

16 hours ago | 0

Answered
How to convert a 'char' into 'double' data type without disrupting the data?
You could try adding back in the '0' that you subtracted to create DoubleC from C, but keep in mind that not all the values in I...

20 hours ago | 0

Answered
Finding the position of specific value in a vector without knowing the exact number
Depending on how you're storing your data and what analysis / manipulation you want to perform on it, storing it in a timetable ...

20 hours ago | 0

Answered
Remove time from datetime
Use timeofday to create a duration array containing the time since midnight for each of the datetime arrays. rightNow = datetim...

21 hours ago | 0

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Answered
How to solve preallocating speed of a variable?
You start off with car an empty double array, then change it to a struct array with your first assignment in the loop. Instead I...

23 hours ago | 1

Answered
How do I change the default background color of view(biograph) objects created in MATLAB?
I don't believe you can do what you ask. If you're not required to use the biograph object consider using a graph or digraph ob...

2 days ago | 1

Answered
Invalid use of operator.
int = sqrt(@(t).* (av(t))^2); That is not valid. You're not multiplying the square of av(t) by anything. int = sqrt(@(t) (av(t...

2 days ago | 0

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Answered
What is the default MathWorks recommended compiler for mex compiling C++ source files that require Intel MKL as linear algebra package?
See the page linked in the appropriate row of the "Supported Compilers" column of the table on the system requirements page. Tha...

2 days ago | 0

Answered
How to locate and link with the exact same Intel MKL that MATLAB is shipped with?
See this documentation page.

2 days ago | 0

Answered
hypercube or hyperpca not found. Not even in R2020b .why ?
Both those functions are part of Image Processing Toolbox. Check the output of the ver function to determine if you have this to...

2 days ago | 0

Answered
Object properties that automatically update but aren't Depenent
function obj = set.P(obj,pressure) if ~isempty(obj.P) error('Pressure is already set, please change pressure via s...

2 days ago | 0

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Answered
How do I convert a date time format that's (dd-MMM-yyyy hh:mm:ss) to (dd-MMM-yyyy hh)?
Do you want to change the displayed value or the stored value? dt = datetime('now') dt_display = dt; % Make a copy so dt can b...

3 days ago | 0

Answered
matlab 2021-a
In "the March timeframe". We don't give the specific release date ahead of time.

3 days ago | 0

Answered
ode45 error: must return a column vector
When you call your function at the initial time and conditions you pass into ode45 does it return a column vector? [I commented ...

3 days ago | 0

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Answered
The Simpson's 1-3 (h / 3) method in Matlab
% Ask for user input % Lower bound (a) a = input('What is your lower bound (a)?') % Upper bound (b) b = input('What is your ...

3 days ago | 0

Answered
Store a vector in one function and access it from another function in Appdesigner.
See this documentation page.

4 days ago | 0

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Answered
Dos command doesn't work through Matlab, and works OK in command window
You cannot use double quotes both to surround the command and inside the command, at least not that way. Something like this wou...

4 days ago | 0

Answered
Hello, can you help me with drawing up such a scheme, what source data is needed and in what form and how to enter them into the program (Matlab Simulink)?
Section 5 of the paper to which you linked seems to explain the meanings of most if not all of the identifiers given in that Sim...

5 days ago | 0

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Answered
Error using atan2 Inputs must be real.
Set an error breakpoint and run your code. When MATLAB stops on that line, look at the values you're passing into atan2 in the c...

5 days ago | 0

Answered
Quotes matlab please help
What layout is your keyboard setup? On my 104 key US-QWERTY the single quote character used to create a char vector is immediate...

5 days ago | 0

Answered
Do anyone know how to graph your function in the interval from x=0 to inf
The fplot function allows you to specify the range of x over which you want your function to be plotted. syms x fplot(sin(x), ...

6 days ago | 0

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Answered
Solution to time and space dependent ODE
See the ode45 function and the example on its documentation page that discusses passing additional parameters into your ODE func...

6 days ago | 0

Answered
-If else- conditionals in matlab app.designer?
Compare: 'ac' == 'ad' % returns a 1-by-2 logical array 'ac' == "ad" % returns a 1-by-1 logical array When you compare two cha...

6 days ago | 1

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Answered
nlinfit command problem :(
From the error message: "Weights must be a vector of real positive weights ..." Are they? Is dA a vector? Check with isvector. ...

6 days ago | 0

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Answered
How do I input and solve a system of differential equations in matlab
I recommend you visit the Ordinary Differential Equations category in the documentation. Several of the Topics pages listed in t...

7 days ago | 0

Answered
User inputs for publish
To me, publishing is intended as a non-interactive activity. You should be able to start the publishing process, go get a cup of...

7 days ago | 1

Answered
How does mat2cell work?
Let's try this with a slightly smaller matrix, so you can see what's going on. A = reshape(1:24, [3 8]) Let's slice this into ...

7 days ago | 0

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Answered
How do I do a Matlab assignment (report)?
Assuming this is homework, you should probably ask your professor about the format of the report they expect you to submit. You...

8 days ago | 0

Answered
I have a question
You did not end the command you executed immediately before calling imshow(d) with a semicolon. I'm guessing that command was a ...

8 days ago | 1

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