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Steven Lord


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MathWorks

5 215 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
what kind of license do I need?
I advise you to contact the Sales department and work with them to determine the license configuration that will best meet your ...

environ 4 heures ago | 0

Answered
Random generator with constraints
A = rand(6, 4); [~, ind] = sort(A, 2)

environ 4 heures ago | 1

Answered
Using a string to pass input argument to a function
Use comma-separated lists (CSL). The "How to Use the Comma-Separated Lists" section on that page shows both how to use CSL to pa...

environ 4 heures ago | 1

Answered
How to find eigenvalues and eigenvectors without using built-in functions (Ex. eig)?
Without using any built-in functions? It depends -- do you consider the commands used in MEX-files to be built-in functions? In ...

environ 5 heures ago | 0

Answered
How can I surface plot a 1000x2 matrix?
What does the data represent? X and Y coordinates of the points? If so where's the Z data? Or do you have a long, thin sheet of...

environ 6 heures ago | 0

Answered
Symsum returns symbolic expression instead of value
What makes you believe that this summation converges? syms m f = sinh(16*pi*m/3)./sinh(4*pi*m/3); fplot(f, [0 10]) This term...

environ 7 heures ago | 0

Answered
Single prompt for large set of variables
How huge is the "huge set of variables"? If your function requires the user to enter hundreds or thousands of values, I would ad...

environ 7 heures ago | 0

Answered
showing hours elapsed not date and time data
How are you importing this data from Microsoft Excel? See if the function or technique you're using to import the data can impor...

environ 7 heures ago | 0

Answered
computing function with a variable
%{ x0=[1;2;3;4]; d0=[1118,-124,-502,-1090]; F=(x1-10*x2)^2+5*(x3-x4)^2+(x2-2*x3)^4+10*(x1-x4)^4; %} F is not a function. As...

environ 7 heures ago | 0

Answered
Not enough input arguments
You need to call your function with two input arguments. You've called it with zero or one.

environ 8 heures ago | 0

Answered
Missing data with a time range
retime your timetable to a regular time basis.

environ 8 heures ago | 0

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Answered
Why isn't my code working because of delimeters?
10(t(n)+1) is not valid syntax in MATLAB. You need to explicitly perform the multiplication, 10*(t(n)+1).

environ 19 heures ago | 0

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Answered
Change the zeros to ones and the ones to zeros.
Let's look at V after the second and third steps: V = [ 1, 1, 1, 1, 0, 1, 0, 1] V(V==0) = 1 V(V==1) = 0 You want to record w...

1 jour ago | 0

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Answered
Values from workspace change
Home is an int8 array. When you combined the int8 data with the double data, the double data was converted to int8. See this doc...

1 jour ago | 0

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Answered
The same script works perfectly on Matlab and does not on app designer
My guess is that when you call the function in the Command Window or script you're calling it on scalar data but when you call i...

1 jour ago | 0

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Answered
Error using sym/subindex (Bessel function)
syms k t = 0:1:100; rho = 1000; mu = 0.001; dp = 1; R = 0.05; l = 1; ram = besselzero(0,11); Since you haven't showed us...

1 jour ago | 0

Answered
Error using plot Data must be numeric, datetime, duration or an array convertible to double
Let's look at what you're trying to plot. x=[1680 1190 841 595 420 297 210 149 105 74.4 52.5 37.2 26.3 18.6 13.1 9.29 6.57 4.6...

1 jour ago | 0

Answered
How to use indexed function output as a function of original inputs?
Dot notation is indeed not defined for function handles. You can't do: f = @sin; % Commenting this code that would error so th...

1 jour ago | 0

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Answered
How can I join unequal vectors by adding NaN values?
The NaN function (along with inf, zeros, and ones) behaves in a way that will help you. Negative sizes are treated as 0. a = Na...

1 jour ago | 0

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Answered
How can I solve the issue showing the error " Wrong use of the `max` data type is invalid". "The first argument must be a numeric or logical value" in matlab
The max function is not defined for cell array inputs. If it were, what would you expect the result of max to be if called on th...

1 jour ago | 1

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Answered
Help with simple bisection method function while loop
Let's say your function was: f = @(x) -x.^2; and your tolerance was 1e-6. Is the tolerance satisfied if I evaluate f at x = 1?...

2 jours ago | 0

Answered
Matlab Bisection Algorithm code
This bisect(sin(x),pi/2,1.5*pi,10^-6,100) attempts to call the sin function with the contents of the variable x as input and u...

2 jours ago | 1

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Answered
error: Array indices must be positive integers or logical values.
m=(1/((kw(di)^2 ... There's no such thing as element 0.05 of an array in MATLAB. Perhaps you're missing a multiplication sign t...

2 jours ago | 0

Answered
Unwanted negative solution with ode solver
Either: specify the NonNegative option using odeset to control which components of the solution are not allowed to become negat...

2 jours ago | 0

Answered
Multi Dimension Matrix Elements multiplication
If you're using release R2020b or later, see the pagemtimes function.

2 jours ago | 0

Answered
ode45: use span of length 2
If you want to only evaluate the solution of your ODE at a specific set of times even if that set of times has only two elements...

2 jours ago | 0

Answered
Error: File: centraldiff.m Line: 1 Column: 11 Unbalanced or unexpected parenthesis or bracket
When you define your function, the function declaration line should include the names of the variables into which the input argu...

3 jours ago | 0

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Answered
Making animatedlines that dynamically change linestyle depending on conditions
h = animatedline('LineStyle', '-'); axis([0 360 -1 1]) for x = 0:360 if mod(x, 30) == 0 addpoints(h, NaN, NaN); ...

3 jours ago | 0

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Answered
Versions at End-of-Life
See the Road Map on the system requirements page. If there is a specific release and operating system combination not on that l...

3 jours ago | 0

Answered
Multiply Even Variables in an Array
Hint: use logical indexing twice in the onle line of code that performs this replacement.

3 jours ago | 0

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