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Steven Lord


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MathWorks

5 203 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
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...

environ 3 heures 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...

environ 6 heures ago | 0

| accepted

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...

environ 6 heures ago | 0

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...

environ 7 heures 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...

environ 7 heures 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...

environ 8 heures ago | 0

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...

environ 8 heures ago | 0

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...

environ 8 heures 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?...

environ 23 heures 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...

1 jour 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...

1 jour 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...

1 jour ago | 0

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

1 jour 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...

1 jour 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...

1 jour 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); ...

2 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...

2 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.

2 jours ago | 0

Answered
Time difference in 'HH:mm:ss,SSSSSS' format
t0 = '15:30:25,123456' t1 = '16:45:30,123457' theFormat = 'hh:mm:ss.SSSSSS'; timeStart = duration(replace(t0, ',', '.'), 'I...

2 jours ago | 1

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Answered
error in using the function fsolve to find steady state
Don't try using a numeric solver like fsolve on a function that returns symbolic answers. Use the solve function from Symbolic M...

2 jours ago | 0

Answered
What are symbolic variables in MATLAB? How they are different from normally used variables?
Symbolic variables are instances of a class provided as part of Symbolic Math Toolbox. That documentation for MATLAB does not li...

2 jours ago | 1

Answered
Password issues with downladed software
Have you contacted Springer directly to ask them for the password?

3 jours ago | 0

Answered
Undefined function 'ln' for input arguments of type 'double'.
The natural logarithm function in MATLAB is named log not ln. There are also log10 and log2 functions listed in the See Also sec...

3 jours ago | 1

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Answered
Computation on arrays using loops
Since you seem to be describing change point detection, see the ischange function and/or the Find Change Points task in the Live...

3 jours ago | 1

Answered
Check if Lat, Lon coordinate fall inside a polyshape Polygon
I would vectorize the calculations. Let's make a simple polyshape: P = polyshape([0.75 0.3 -0.4 -0.1 -0.6 -0.3 0.5], [0.1 0.6 0...

3 jours ago | 0

Answered
how to change order of legends?
You can specify the handles in a particular order when you create the legend. % Sample data x = 0:360; y1 = sind(x); y2 = c...

3 jours ago | 0

Answered
How to highlight isolated nodes in a graph?
You want to highlight those nodes that are not connected to any other? G = graph(sprand(10, 10, 0.05), 'upper'); h = plot(G); ...

3 jours ago | 1

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Answered
Assign placement choices to student identifying their top three
See the matchpairs function.

3 jours ago | 0

Answered
how to normalize a matrix?????
Use the normalize function with a dim input and the 'range' normalization method.

4 jours ago | 0

Answered
Implementation of the feedforwardnet Neural Network
How are you handling the preprocessing functions and postprocessing functions? net = feedforwardnet([2]); net.inputs{1}.proces...

4 jours ago | 0

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