Steven Lord

MathWorks

Last seen: Today | Active 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
Sorting numbers that the largest is at a specified index, and then progressively smaller in both directions
x = [17 2 3 5 11 7 13] s = sort(x, 'descend') y = [flip(s(2:2:end)) s(1:2:end)]

ongeveer 2 uur ago | 0

Answered
Confusion with tic-toc and run times
What does your shorttimeoptimised function return? Does it return how long the operation took to run or does it return the resul...

ongeveer 3 uur ago | 0

Answered
How to add seconds to a HH:mm DateTime array ?
Do you want to actually add seconds to the value (changing the time) or do you want to add seconds to the display (leaving the t...

2 dagen ago | 0

Answered
pca function returns the wrong output in R2022a
Let's check that you're using the pca function included in Statistics and Machine Learning Toolbox. What does this command show?...

2 dagen ago | 0

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Answered
What is the difference between int8(0x98), uint8(0x98), typecast(uint8(0x98), 'int8')
If you use the following syntax, you create a uint8 value and then cast that value to int8. Since the uint8 value is larger than...

2 dagen ago | 2

Answered
double conditional in one line
At the beginnnig looks like weird >> x=0.23: 0<x<1 This does not ask the question "Is x between 0 and 1 exclusive?" It is inst...

3 dagen ago | 1

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Answered
"y-direction of the coordinate system should be reverted"
Images and "regular" plots have different conventions for whether the Y axis should be increasing or decreasing as you move towa...

3 dagen ago | 0

Answered
Couldn't find helperVisualizeScene() function
Open the example in MATLAB using the command that gets copied to the clipboard when you press the "Copy Command" button. MATLAB ...

3 dagen ago | 1

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Answered
comparison between a string/or cell and categorical data
MATLAB is correct. Sis(1).Trading = 'As Is' Trading(1) = categorical({'As is'}) Sis(1).Trading==Trading(1) If you used a cap...

4 dagen ago | 1

Answered
Error using image Color data must be an m-by-n-by-3 or m-by-n matrix. Error in imagesc (line 52) hh = image(varargin{:}, 'CDataMapping', 'scaled');
As the error message says, the image data you pass into imagesc must be a matrix (if it's an indexed image or a grayscale intens...

5 dagen ago | 0

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Answered
How to create a "scatter" matrix without using a for loop?
row = [1,2,3]; col = [2,4,4]; val = [123,321,456]; M = accumarray([row.', col.'], val.', [4 4])

6 dagen ago | 0

Answered
Code protection in deployed standalone application
See this documentation page for more information about the deployable archive and the Wikipedia page for more information about ...

6 dagen ago | 0

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Answered
receiving different training results while running the same code
Are random numbers involved in the process of creating or training your RL model? [My guess is most likely yes.] One way to chec...

6 dagen ago | 1

Answered
Accelerate a loop involving the built-in integral command
Assuming that params doesn't change, consider using the memoize function to create an object you can use in your integrand funct...

6 dagen ago | 0

Answered
PSO does not satisfy the nonlcon inequality constraint and gives solutions less than LB
Have you considered using the particleswarm function in Global Optimization Toolbox, either as your main solver or to help you d...

6 dagen ago | 0

Answered
Can't use pca() function - Error using statset No default options available for the function 'pca'.
Let's make sure you're using the pca and statset functions included with Statistics and Machine Learning Toolbox rather than oth...

6 dagen ago | 0

Answered
Plotting different sized vectors
If you have an idea in your mind of roughly what you want the plot to look like, open the Plots tab of the Toolstrip and click t...

7 dagen ago | 0

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How to convert time in microseconds (queryperformancecounter(qpc)),import from an excel file, to time (hh:mm:ss)?
You can convert a number of microseconds into a duration or (if you know the epoch time) into a date and time value. M = 168892...

7 dagen ago | 0

Answered
Looping scatteredInterpolant across each frame in 3D matrix
Using the variable names given on the scatteredInterpolant documentation page, do you mean that your xgrid variable is the x inp...

7 dagen ago | 1

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Answered
How to run .m file through terminal on linux ?
Try starting MATLAB with the -batch option.

8 dagen ago | 0

Answered
examples in the vision toolbox fail to load .mat files
The pointCloud function is part of Computer Vision Toolbox and was introduced in release R2015a. Do you have this toolbox instal...

8 dagen ago | 0

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Creating a polar histogram with x values (bins) that will appear on the graph even though no values fall into those bins?
Do you need the histogram to be on a polar axes? If so use the polarhistogram function. x = deg2rad(randi([0 270], 1, 1e6)); p...

8 dagen ago | 0

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Answered
Some Robot models are missing from the Robotics System Toolbox.
According to the Release Notes the puma560 robot model was introduced in release R2023a. You're using release R2022b, the releas...

8 dagen ago | 1

Answered
Retime for custom timestep (6 hour)
You're using this syntax from the retime documentation page: "TT2 = retime(TT1,'regular',method,'TimeStep',dt) calculates regul...

8 dagen ago | 0

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DE (f) has wrong solution
Your code calls ode45 with an output argument but then doesn't use that output argument later in the code. In addition you're ca...

8 dagen ago | 0

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Process .dat file, plot, scale, and put back into similar format
You may want to interactively experiment with the various options for importing your data in the Import Tool. You can specify th...

9 dagen ago | 0

Answered
Creating a Dynamic Variable for Table Names
Can you dynamically create variables with numbered names like A1, A2, A3, etc.? Yes. Should you do this? The general consensus ...

9 dagen ago | 0

Answered
How to request the development of a new support package?
If you're requesting support for a new type of hardware, see this page. If you're requesting a different type of support packag...

9 dagen ago | 0

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Answered
code fft for matlab function block
Are you sure you intended to take the fft of the input argument S? From the error message that input is a scalar (or a length th...

13 dagen ago | 0

Answered
How to label nodes in a plot?
This matrix looks similar to the one from one of your previous questions. If that's the case, and you plotted the graph object, ...

13 dagen ago | 0

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Steven Lord

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