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Steven Lord


MathWorks

2.963 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
Working with table.
Do you need your data to be stored in a table or would a timetable be acceptable instead? Offhand I can't think of anything you ...

ongeveer 11 uur ago | 0

Answered
Undefined function 'eq' for input arguments of type 'timetable'.
For this particular application, I recommend using standardizeMissing.

1 dag ago | 1

| accepted

Answered
How can I group a timetable in hours 0-24h
See the "Aggregate Timetable Data and Calculate Mean Values" example on the retime documentation page. While that uses a duratio...

1 dag ago | 0

Answered
I keep getting the message: Unbalanced or unexpected parenthesis or bracket. How would I fix it? I'm trying to solve for the maximum and minimum with a function and it's constraint.
T = [ ax ay subs(g,{x y},{ax ay}) subs(f,{x y}, {ax ay })({bx by}) ... subs(g,{x y},{bx by}) subs(f,{x y}{bx by})] This p...

2 dagen ago | 0

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Answered
What is the meaning of 'simplify(n./d)?
The expression n./d divides each element of n by the corresponding element of d (with a few caveats to that if they're different...

2 dagen ago | 0

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Answered
how to get matlab 2019b
The latest release as I type this is release R2019a. Release R2019b is not out yet. If you want to use release R2019a, check wi...

4 dagen ago | 0

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Answered
How can I extract values from a histogram (figure)?
If you only have access to the figure file, use openfig to open it in a figure window then use findobj to obtain the handle of t...

5 dagen ago | 0

Answered
Why doe the data extracted from excel sheet gets converted to scientific power ?
To change the way the data is displayed (which will not impact how it is stored) use the format function.

5 dagen ago | 0

Answered
How can I force a non-trivial solution for a second order ODE
Your equation is x''=[ 9/4-(12/(5-3exp(2t)))exp(2t)] x(t) with initial conditions x'=x=0. You are a racecar at the starting line...

6 dagen ago | 0

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Answered
How can I average datetimes of my array?
Convert your table to a timetable using table2timetable. Once you have your timetable call retime on it.

6 dagen ago | 0

Answered
row dimension of aeq is inconsistent with length of beq. Help me pls.
You passed the inputs into fmincon in the wrong order. From the documentation page, the syntax you're calling is: x = fmincon(f...

6 dagen ago | 0

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Answered
Pan does not work
Run this command: which -all pan From the error message it sounds like you've created a Simulink model named pan that is takin...

6 dagen ago | 0

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Answered
how tocreate a new array that select the columns with a specific prefix in the header row
Read your data into a table array using readtable. Since I don't have your spreadsheet, I'll just create a sample table using th...

7 dagen ago | 1

Answered
Re-hash the intrinsic Matlab plot function to accept a string as a y input?
You could turn your text data into a categorical array then plot with that categorical data as the Y input. colors = categorica...

8 dagen ago | 1

Answered
I got "The expression to the left of the equals sign is not a valid target for an assignment."
Just eliminate that line from your code. The way you've defined x on the next line will make it complex since i is already defin...

8 dagen ago | 0

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Answered
Dynamic size differential equation system
There's no need for a loop here. Work on vectors. function dvhdt = myodefun(t, vh, alpha, optV, beta) % Compute N from the vh ...

8 dagen ago | 0

Answered
Blackjack Program -- Random Card Deal
Deal 4 cards from the deck at once. Give the dealer the first two and the player the next two. As written, your code can give t...

10 dagen ago | 0

Answered
symbolic variable multiplication with numerical matrix
When you perform that multiplication, Symbolic Math Toolbox converts your numbers into rational numbers rather than leaving them...

10 dagen ago | 1

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Answered
Resetting individual properties to default values: 2018b
The most straighforward way is probably to define a Hidden, Constant property holding the default value. Since it's Hidden it wo...

11 dagen ago | 0

Answered
How mink functions is used in 2016a or is there any alternate of this function ?
As stated at the end of the documentation page for mink, this function was "Introduced in R2017b". It does not exist in release ...

12 dagen ago | 0

Answered
syms wrong message, definition
syms creates an Inf value as part of its operation, and you've enabled an error breakpoint that causes MATLAB to enter debug mod...

13 dagen ago | 0

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Answered
suptitle in 2016a
If you are using release R2018b or later, I recommend using the sgtitle function instead of suptitle. subplot(2, 2, 1); plot(1...

13 dagen ago | 0

Answered
How can I create this 2D waterfall plot?
That's not a waterfall plot, at least not by my understanding. To me a waterfall plot looks like the picture shown on the waterf...

13 dagen ago | 0

Answered
Increasing Speed of Execution
Try the ischange function.

13 dagen ago | 1

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Answered
How can I represent the mean in figure
You can 'center' your data using the normalize function. As for "represent the data in figure" do you mean you want to plot the...

13 dagen ago | 0

Answered
Access different property from set method in class
As long as the get method for the useGpu property doesn't try to set the smaps property (leading to an infinite loop) and as lon...

13 dagen ago | 0

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Answered
New to MATLAB, question about num2str
I recommend not using datetime as the name of your variable as it already has a meaning in MATLAB. If you want to use a datetime...

13 dagen ago | 1

Answered
realmax + 1 infinity?
If you handed Bill Gates or Scrooge McDuck a $1 bill, it doesn't change what he'll report for his net worth. A single dollar is ...

13 dagen ago | 1

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