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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
I need a function or equivalent code fgetl, but it is very fast.
Are you sure that fgetl is what's taking the time? Or are you trying to read data one line at a time from a file and storing eac...

19 hours ago | 0

Answered
Separate date and time
dt = datetime('now') % Sample data theTime = timeofday(dt) theDate = dt - theTime % or theDate2 = dateshift(dt, 'start', 'day...

19 hours ago | 1

Answered
Look for string in table and return a number in the same row different column
I'd probably use matches for text data (and the normal relational operators for numeric data.) load patients P = table(LastNam...

21 hours ago | 0

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Answered
Invalid expression error when I try to introduce new variable.
It's likely (in the absence of nested functions) that the statement on line 407 is not inside any function. The end on line 405 ...

1 day ago | 0

Answered
Install a toolbox from command line?
I would probably use the silent installation process.

2 days ago | 0

Answered
Out of memory issue
sz = [196608 4096]; numberOfElements = prod(sz); bytes = 8*numberOfElements; gb = bytes/1024^3 Each subset is 6 GB in size (...

2 days ago | 0

Answered
change the first digits when ends with 5959
Is there a reason you're starting with string data first rather than using a duration array from the start? d = minutes(0:0.25:...

2 days ago | 0

Answered
How do I use a user input string to reference a structure that already exists?
I have multiple users with different structure names that need to use this. I want them to be able to input their structure name...

2 days ago | 1

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Answered
Issue with numerical integration of two variable function
A = @(x, y)cos(x)+sin(y); B = @(x, y)(A-integral(@(x)A, 0 , 2*pi)); Your expression for B won't work for two reasons. The inte...

2 days ago | 0

Answered
What is wrong with A = alter(a)?
which -all alter What function are you trying to call? From the tag can I assume you're trying to use Computer Vision Toolbox?...

3 days ago | 0

Answered
How to place NaN instead of " " / [ ] or empty field by using standardizeMissing?
My guess is that the data that was read into that 7th variable in your table was not numeric data but included data that MATLAB ...

3 days ago | 0

Answered
Is the Abstract keyword needed to make a method abstract?
That is valid syntax, but not for making my_method an Abstract method. What you've written tells MATLAB that my_method is implem...

5 days ago | 0

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Answered
Standalone application cannot read p-code?
Standalone apps cannot run any MATLAB code that was not included in the application at compile-time. From the documentation "MAT...

5 days ago | 1

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Answered
Tiny discussion on good practices in object oriented programming (OOP) through a simple example
First, having two classes whose names differ only by casing or by the difference between singular and plural seems likely to cau...

5 days ago | 0

Answered
Files generated during testing are not saved
I second Geoff Hayes's question about where you're creating these files. Are you putting them in a directory created using a Tem...

6 days ago | 0

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Answered
Retrieve curve fit coefficients
What "something else" are you planning to do with this fit information? There are a number of post-processing operations you can...

7 days ago | 1

Answered
Does Matlab support coding of embedded systems and robotics
Take a look at the Robotics and Autonomous Systems and Embedded Systems sections linked from the Solutions section of the websit...

7 days ago | 0

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Answered
How to save multiple output?
In your code: %{ for i = 1:m [A,x,y]=myfunction(I,vals(i,1), vals(i,2)); end %} is A always going to be the same size? If ...

7 days ago | 1

Answered
How to add black isolines for f(x,y) = -1, 0, 1
Use the contour or contour3 functions.

7 days ago | 0

Answered
Dealing with Data Structures
Can you create variables named impact_data0, impact_data1, impact_data2, etc.? Yes. Should you do this? The general consensus i...

8 days ago | 0

Answered
Warning: Function class has the same name as a MATLAB builtin. We suggest you rename the function to avoid a potential name conflict
You've created or downloaded a file named class.m that's preventing MATLAB from calling the built-in class function. Identify th...

8 days ago | 1

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Answered
Extracting value from Name-Value pairs using the Name string
test = struct('units', {'degrees_east', 'degrees_north'}, ... 'long_name', {'longitude', 'latitude'}) theNames = {test.lon...

8 days ago | 0

Answered
How do I get an Expression to Use the Value of a Variable that was Assigned after the Expression was Defined?
Use subs. syms z f = 2*z z = 4; f g = subs(f)

9 days ago | 0

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Answered
What is the equivalent of mmult of excel in matlab?
The * operator performs matrix multiplication, but in order for that operation to be mathematically defined you need to transpos...

12 days ago | 1

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Answered
Cut a graph ?
If the data to be plotted includes NaN, that point will not be plotted. x = 1:5; y = [1 2 NaN 1 2]; plot(x, y) axis([0 6 0 3...

12 days ago | 0

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Answered
Histogram occurences per age problem
Use the histogram function instead of histc.

13 days ago | 1

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Answered
How to assign strings and numbers to elements of the same matrix?
Do you need your data stored with mixed-type columns or would mixed-type rows work? If the latter, consider a table array. Resu...

13 days ago | 0

Answered
Passing additional argument into objconstr
Adapting the example from the documentation page for packfcn: ros = @(x, k) k*(x(2) - x(1)^2)^2 + (1 - x(1))^2; % Added a param...

14 days ago | 0

Answered
Use of Genetic Algorithm feature for optimization of technical design
What signature does the documentation page for the ga function state your nonlinear constraint function must have? [How many inp...

14 days ago | 1

Answered
Transpose pivot reshape a MATLAB table from a cross-section wide 'row format' to a panel-data long 'column' format
I'm not sure where those 4444 values came from in your second T variable, but I think what you want is to stack your table data....

14 days ago | 0

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