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Steven Lord


MathWorks

3,661 2002 年以降の合計貢献数

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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ODE triggered event does not stop
Your event function shouldn't use the relational operators itself. The only possible values your events can take on are 0 and 1 ...

約23時間 前 | 0

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finding special date time
Find the next Sunday after a given date. T = datetime('today'); nextSun = dateshift(T, 'dayofweek', 'Sunday', 'next') All Sun...

1日 前 | 0

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Can anyone tell me the error with sum function?
Based on prior experience, I suspect you received the error "Array indices must be positive integers or logical values." If that...

1日 前 | 0

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How to keep the precision of datetime when taking into consideration time offsets
You don't actually want a datetime array, you want a duration array. That's easy. First remove the fractional seconds. There's n...

1日 前 | 2

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Call function multiple times but execute once
I think it unlikely that ga is calling your function with exactly, down to the last bit, the same inputs multiple times. It's li...

2日 前 | 1

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Out of memory (infinite recursion) running a stochastic collocation
[mean, stdev] = Stochastic_Collocation(x,nomforce); You call your function inside itself, which causes your function to cal...

3日 前 | 1

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Issue with atan2(.)
The atan2 function included in MATLAB requires exactly two input arguments. Therefore you're likely calling a different atan2.m ...

3日 前 | 0

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Pre-allocating memory for a while loop
I'm running a code that is based on a while loop to similate a chemical process. It simulates an added amount of species each se...

3日 前 | 0

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Is there any option to use boxlabelDatastore function in Matlab 2017b?
This function was introduced in Computer Vision Toolbox in release R2019b according to the note at the end of its documentation ...

3日 前 | 0

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Wrong left and right assignment error
for n= 1:1:100 l(n) = n.*(a.*b.*c); When you execute that second line of code, n is a scalar (size 1-by-1.) The variables ...

3日 前 | 0

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wlan toolbox is incompleted
There's a note at the end of the documentation page that states this function was introduced in release R2019a. If you're using ...

6日 前 | 0

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Using now() in different time zones (or with daylight saving time)
If you want control over the time zone, you probably want to use datetime instead of now. N1 = datetime('now', 'TimeZone', 'loc...

6日 前 | 0

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How to override inherited methods?
You can't do what you asked. If you could, you could relax the property setting validation to the point where your subClass inst...

7日 前 | 0

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Why is format long providing a strange result?
I recommend using format longg instead of format long for this case.

7日 前 | 1

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Set properties of child objects without synchronisation errors
Let's take a step back from the code for a second. Can you describe the design of your system for which this set of classes will...

7日 前 | 1

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How to require a custom class type with addRequired?
You probably want to use addParameter instead of addRequired. If you're using release R2019b or later, consider using function ...

7日 前 | 0

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Replacing <undefined> in categoricals or defining a default value
You could fillmissing to fill in the <undefined> entries, but if you want to leave them as missing data for future processing yo...

7日 前 | 0

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How would I use Voronoi and/or Delaunay Triangulation methods for information on polygons
Why not just create a polyshape or an array of polyshape objects on which to operate? The NumRegions property gives you the numb...

7日 前 | 0

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How to solve a ODE that is a function of a cubic polynomial f(x) = 0?
This doesn't look like a system of ODEs. The presence of the variable d in the first set of curly braces threw me for a second, ...

8日 前 | 0

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Why is my for loop getting faster and faster?
This doesn't strike me as a bug. I suspect this is due to the execution engine introduced in release R2015b (which uses just-in-...

8日 前 | 0

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cannot modify plot axes as per documentation
Can you post the exact URL for the documentation page that says you can change the plot units by right-clicking, so we can see e...

8日 前 | 1

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LDU factorization matrices help.
Use the ldl function.

9日 前 | 0

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Find the data same week day one year ago.
You want the date exactly 52 calendar weeks ago? datetime('today')-calweeks(52)

10日 前 | 0

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Derivative using datenum format vector
Use the minutes function to compute the difference between two elements of a datetime array (or two datetime arrays) in terms of...

10日 前 | 0

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ode45 for 4 DOF system - How to do with Matrices?
Is there a reason you're computing the inverse of the mass matrix and performing that multiplication instead of using odeset to ...

10日 前 | 0

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simulering.m Line: 17 Column: 7 Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.
for v_(size(t))=v_(size(t)-1)+f*i*F_red-Q_ud; That's not valid MATLAB syntax. It looks like you may be trying to create variabl...

10日 前 | 0

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Compare nearby elements in array
I think the islocalmax function, specifying both the dimension over which to operate and a 'ProminenceWindow', will do what you ...

10日 前 | 0

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Decision Branching Error in matlab onramp
That might be checking that the densities that are printed as text when doPlot is 0 exactly match the densities that would be pr...

11日 前 | 1

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Solving Linear System of Equations with a Real Parameter
What do you know and what are you trying to find? Do you know the value of and you're trying to find the X values? If so, build...

11日 前 | 0

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How to set title for matlab.graphics.primitive.Image ?
|image| objects don't have either a String or a Title property. The |axes| in which |image| objects are contained don't have a S...

11日 前 | 0

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