Steven Lord

Last seen: Today

MathWorks

5,253 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
Array indices must be positive integers or logical values.
Nn=1:2:30; This is valid MATLAB code. Nn(i)=60; As long as i has been defined as an array containing only positive integer va...

3 hours ago | 0

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errors in sortrow in matlabr2020
"Column sorting vector must contain integers with absolute value between 1 and the number of columns in the first argument." Ho...

5 hours ago | 0

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function used for grading, :how do i get it to work?
I would do my input argument checking up front. Why go through the effort of classifying data that I know is invalid? if mark >...

5 hours ago | 0

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Error using quad (line 70) The integrand function must return an output vector of the same length as the input vector. Error in sprawozdanie1 (line 37) Ssr=quad(x1,-0,6*pi);
x1=@(t)x; x is a numeric vector. That vector is not necessarily the same size or shape as the array t that quad passes into you...

6 hours ago | 0

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Is there any limitation with fimplicit and fimplicit3 when functions have sqrt ?
Let's look at the value of your function at one of the corners of the region on which you want to plot: R = 0.35; L = 0.264;...

6 hours ago | 1

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Finding local minimums/maximums for a set of data
For more recent releases take a look at the islocalmin, islocalmax, and (perhaps) detrend functions.

1 day ago | 0

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Eigenvector different to expected using eig
A=[1.5 -0.5; -1 1]; [Vec,Val]=eig(A) What does the eig function return? From its documentation: "[V,D] = eig(A) returns diag...

1 day ago | 1

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Answered
Extreme difference between the value of a function and the result in matlab
One of the terms in your expression involves b^8. For b = 30000 what is the value of that term? b = 30000; b8 = b^8 That valu...

1 day ago | 0

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what does MatLab Home license cover?
For official answers to these licensing questions please contact Customer Service using the "Contact Support" link on the Suppor...

1 day ago | 0

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sym error in define functions
As the error message states, "To evaluate character vectors and strings representing symbolic expressions, use 'str2sym'." So u...

1 day ago | 0

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Answered
How to write a short syntax for the legend?
Set the DisplayName property of each line just like you set the LineWidth. Then legend show will make the legend appear and use ...

1 day ago | 0

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hour of datenum type
What is the full and exact text of the error messages they receive? Show all the text displayed in red (and if there is any text...

2 days ago | 0

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Solve system of linear equations ...matrix output is not as expected
A being a 9-by-9 matrix is correct. syms A11 A12 A13 A21 A22 A23 A31 A32 A33 real; eq1 = A11*-0.001179+A12*-6.581+A13*0.008...

2 days ago | 0

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Answered
How can I do to enable zoom only for a specific axes?
Call zoom with an output. Call setAllowAxesZoom on that object. See the "Object Functions" section on the documentation page for...

2 days ago | 0

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Task: write matlab code for a class MinAngle which calculates the minimum angle between two bearings (bearing A and bearing B).
The assignment operator in MATLAB is =. The element-wise comparison operator is ==. But you should use neither of those in your ...

2 days ago | 0

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Switching between open files in editor by searching
There is an API you could potentially use for this sort of task. I have my installation of release R2019b open, so I'll just ope...

2 days ago | 0

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Integral Function inside while loop only works for certain values. ArrayValued results in empty volumn vectors.
You probably want to recompute S *while* it is empty not *if* it is empty. Otherwise S could still be empty after the second vpa...

3 days ago | 1

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how do I take the matrix A and a vector with the indexes of the rows to be considered, and takes out a vector of the mean values?
function A(meanValue) = HW3Part3Function A(meanValue) = mean((A(1:2:end,:),2)) When you define your function, the function dec...

3 days ago | 0

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Answered
convert logical values to numeric values
What do you want the double array to represent? Just 0 and 1 instead on false and true? Use Jan's approach. 0 where there isn'...

3 days ago | 0

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Syntax Question, Why does this equal zero?
What happens if you compute it by hand? Start with the expression in the parentheses since they're at the top level of the opera...

4 days ago | 0

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Can I assign a variable to a number in a matrix from another matrix?
There's a way to do this without creating 2*n individual variables. A = magic(7); E = eig(A); w = E(1:3); m = [3; 11; -7];...

4 days ago | 0

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Not Enough Input Arguments
Your function can be called with at most two inputs, and since it uses both inputs on the line you called out it must be called ...

4 days ago | 0

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Convert Text into Date Format
If you have a number: x = 196307; datetime(100*x+1, 'ConvertFrom', 'yyyymmdd') If you have text: y = string(x); datetime(y,...

4 days ago | 1

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represent a function in Matlab
Let's look at your function symbolically. xo = 400; yo = 7000; x = 260; y = 6954; a = 0.5; b =0.4; K = b*xo-a*yo; % t=...

4 days ago | 0

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Fit operation with defined variables
See the "Create Fit Options and Fit Type Before Fitting" example on the documentation page for the fit function. It uses the 'pr...

4 days ago | 1

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Answered
Array indices must be positive integers or logical values.
If x only has one element, x(end-1) is an attempt to access element 0 of x. Arrays in MATLAB don't have an element 0. Their firs...

5 days ago | 0

Answered
How to define these two functions?
The name gamma already has a meaning in MATLAB, and in fact it calculates the function you're trying to evaluate with your anony...

5 days ago | 1

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Answered
How do I calculate this definite integral in matlab
When I encounter a problem integrating, one of my first thoughts is to look at the function I'm trying to integrate over the int...

5 days ago | 1

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use vector as input
So you want to compute the value of e and the time required to compute that value for each element of n? A couple of suggestions...

5 days ago | 0

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How to extend the colon operator for my own class
The colon function in MATLAB for numeric inputs does not return an iterator, it returns a vector. See the documentation page for...

5 days ago | 0