Steven Lord

Last seen: Today

MathWorks

4.631 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
Something is wrong with my Matlab
A = [x x x; x y y; y -2z] b = [60 30 3]' I suspect this is supposed to represent the equations 3*x = 60, x+2*y = 30, y-2*z = 3...

etwa 22 Stunden ago | 3

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Convert/copy array to different type of array (single to uint16 for example) bit by bit
Are you trying to typecast one of the variables into the other?

ein Tag ago | 0

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Variable from function to change value
What's the purpose of your function? Is it simply to score the set of dice (meaning that it's some other function, perhaps its c...

ein Tag ago | 0

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Help calling my basic function
That is the correct and documented behavior. See the first Note on this documentation page. You could do this by either creatin...

ein Tag ago | 1

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Python 3.8 interoperability
The Release Notes for release R2020b indicate that cPython 3.8 is now supported.

ein Tag ago | 1

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Row unity in matrix
>> P = rand(9); >> NP = normalize(P, 2, 'norm', 1); >> sum(NP, 2) ans = 1 ...

ein Tag ago | 0

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Index daily values in TT over many years to determine mean
Use groupsummary with the GROUPBINS input specified as "dayofyear".

ein Tag ago | 1

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Can someone provide me the theory and math behind this function of eigen?
You might find the "Eigenvalues and Singular Values" chapter in Cleve Moler's Numerical Computing with MATLAB, available here, u...

2 Tage ago | 0

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Can't figure out the error in my pcolor line, keep getting color data input must be a matrix error
Please run this command immediately before the line where you call pcolor and show us the output from just before the pcolor cal...

2 Tage ago | 0

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Answered
Error using barrier Objective function is undefined at initial point. Fmincon cannot continue.
What values do you receive when you evaluate your objective function fun at the initial values in the start field of the paramet...

3 Tage ago | 0

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How to modify an anonymous function with another function
As written, y1sig and y2sig aren't function handles. You could make them function handles like this: f1 = @(d) sind(d); f2 = @...

4 Tage ago | 0

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How I can correct this error? "Undefined operator '/' for input arguments of type 'function_handle'."
z=@(x) x(1)+x(2)+x(3)+x(4)+x(5); F1=@(x) 19720+(R*T*log(x(1)/z))-x(6)-4*x(7); You can't divide x(1) by the function handle z. ...

4 Tage ago | 2

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Answered
specifying the horizontal linetype '_' produces an error.
The horizontal and vertical line markers for plots were introduced in release R2020b. If you're using an older release you will ...

4 Tage ago | 2

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Answered
Property access in subclass
As you've defined A and B they are value classes but you're using them like they are handle classes. See this documentation page...

4 Tage ago | 0

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Error using odearguments with a symbolic system of differential equations
Your ODE function can use symbolic calculations internally but it must return a double or single array to the ODE solver. Call d...

5 Tage ago | 0

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I can't find the mistake in the code
I've seen two different conventions for representing polynomials as vectors of coefficients. The one used by functions like poly...

5 Tage ago | 0

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How to extract input variable name when calling to GUI (GUIDE) function?
If you want your app to display the name of the file that was loaded, you should probably have your app accept the filename rath...

5 Tage ago | 1

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System Error (MATLAB R2019a) after update
See Maadhav Akula's answer on this Answers post.

6 Tage ago | 1

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Why do I get these errors in Toolbox package? Help me out
The MCR directories in the directory for MATLAB Compiler should not be on the MATLAB path. If you've added toolbox\compiler\mcr ...

6 Tage ago | 0

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Answered
Error using 'pi' too many input errors with my equation
You're missing * operators after the two calls to pi on the line where you define y, just like you did on the lines where you de...

7 Tage ago | 0

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Answered
Even binned histogram to uneven bins?
Let's make some sample data. x = randi(255, 1, 1e5); Use bin edges that are the squares of the integers between 1 and 16. Each...

7 Tage ago | 0

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Error using subplot using for loops: subplot index too large
Set a conditional breakpoint on the line where you call subplot. The condition is nVals1*4 < indexplot. Run your code. When MATL...

7 Tage ago | 0

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Array of Structures (not structure array)
Consider a struct whose fields are themselves struct arrays. arr.asdf = struct('A', 3, 'B', 2); arr.zxcv = struct('A', 7, 'B',...

7 Tage ago | 1

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Answered
Unable to use CTRL+R to comment
Open the Preferences using the button in the Enviroment section on the Home tab of the Toolstrip. In the MATLAB section of the p...

8 Tage ago | 0

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How to upgrade Matlab Online?
I'm not on the MATLAB Online team but I see in the Application Status page that there was an issue around noon that caused some ...

8 Tage ago | 0

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Setting Limits to end of table Variable
Use bounds and/or min and max on your time data to find the tight bounds and use those with xlim to adjust the limits.

8 Tage ago | 0

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Simplifying a matematical expression
After inserting it into Answers using the sigma button on the toolstrip: Honestly, I wouldn't enter this as one term. As you ...

8 Tage ago | 1

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How can i vectorize a matrix multiplication of higher dimension arrays?
If you're using release R2020b or later, take a look at the pagemtimes function introduced in that release.

8 Tage ago | 1

Answered
How to multiply N matrices without a FOR loop? (Slices of 3D array)
If you're using release R2020b or later, take a look at the pagemtimes function introduced in that release.

8 Tage ago | 0

Answered
Matching string from multiple arrays
If you have your data stored in timetable arrays, call synchronize with your three timetable arrays as input and specify the new...

8 Tage ago | 0