# Steven Lord

### MathWorks

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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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Can't get matrix to populate first column

The smallest value in z is 1. Because you add 1 to z to generate z1, that means the smallest value in z1 is 2. You use z1 to det...

9 hours ago | 0

description of highlighted code

From the variable names and the signature, this looks like a function you wrote or were given as part of solving a system of ODE...

1 day ago | 0

Possible to iterate over table rows without a loop index variable?

To perform an operation on all rows of a table array you could use rowfun, but that isn't the same as writing a general for loop...

2 days ago | 0

| accepted

pcregistericp using GPU Support

Note that "GPU Code Generation" and "GPU Arrays" are two different Extended Capabilities. For example, in MATLAB there are 200 f...

2 days ago | 1

| accepted

ode45 invalid parameter 981/100

When you call odeFunction with g as part of the third input, it is not a symbolic variable. You originally defined it using syms...

3 days ago | 0

| accepted

I need to Fix an Error For Lines 34 & 126

Let's look at your cal_obj function. function z = cal_obj(A,B,MB) n = length(MB); z = 0; for i = 1:n z = z + B(MB(i))*A(i);...

3 days ago | 0

I get an error using fsolve but I don't understand why?

Look at the description of the fun input argument on the documentation page for the fsolve function. The relevant part of that d...

3 days ago | 0

| accepted

Problem with solve() and "Empty sym: 0-by-1".

Let's look at the systems of equations you're trying to solve. Ax = [0 1 0 0; 0 -0.1 0 0.8; 0 0 -4 9; -1 -9 2 -8]; Bx = [0 0 0...

4 days ago | 1

Error using fclose in MATLAB on Mac: "Invalid file identifier. Use fopen to generate a valid file identifier.

When you call fopen you should call it with two output arguments and check if the first is -1. If it is, that means MATLAB and/o...

5 days ago | 0

how do I get my license number?

See this Answers post for instructions on how to determine your license number either from within MATLAB or without having MATLA...

5 days ago | 0

I have a code in python and want to convert it in matlab format

Do you need to convert the code or would being able to run the code in MATLAB be sufficient? If the latter, see the documentatio...

5 days ago | 0

How to Get one Property of a Structure Array Using a Property on the Same Line

You could do what you described by making a non-scalar struct, each element of which has three fields, each of which has a piece...

6 days ago | 0

How to extract numerator and denominator coeficients from polynomial function to array

Do you have separate symbolic expressions for the numerator and denominator or do you have the fraction created by dividing nume...

7 days ago | 0

Error in matlab.internal.doc.csh.DocPageTopicMap/parseTopicPath

Likely you've written your own split.m function that takes precedence over the split function included in MATLAB. What does this...

7 days ago | 0

| accepted

Trouble labeling x and y axis

Do you have a variable named xlabel in the workspace? If you do, you cannot call the xlabel function. Clear or rename the variab...

7 days ago | 0

Maximum recursion limit is reached when I try to open any script

Did you create an open.m file that tries to call open? What does this command show? which -all open

10 days ago | 0

convert a range vector of bin centers to bin edges. Bin Centers and edges are non-uniform

If you know one of the edges of the region you're trying to bin, either the left-most or right-most edge, you can do this. Let's...

11 days ago | 0

How to Fix "Warning: Colon operands must be real scalars" Warning

If you have a small case with which you can reproduce this behavior, could you please send it to Technical Support directly usin...

11 days ago | 0

How to open a directory in Matlab ? Like how do I make the code open a directory ?

I've copied and pasted your code commented out into this message so I can run some sections of code I wrote. This line: %{ % ...

12 days ago | 0

Optimization toolbox installed, but MATLAB says it has been removed

The Optimization Tool interface (optimtool) was removed in release R2021a. The Optimization Toolbox has not been removed. Inste...

12 days ago | 0

how to multiply every single element in a matrix to entire of another matrix?

If you're asking can you dynamically create variables with numbered names like x1, x2, x3, etc.? Yes. Should you do this? The g...

14 days ago | 2

is there a way to make the 0 x and y axis bold?

If you wanted to highlight the X and Y axes by making them cross at the origin, set the XAxisLocation and YAxisLocation properti...

14 days ago | 0

Wrong suming output in simulink r2023A

I don't work with Simulink that much, but I'd check the data types of the various signals in your code. 106 - (-150) The fact ...

15 days ago | 0

Subtracting a Vector from a Scalar-Multiplied Matrix

See this documentation page.

16 days ago | 1

| accepted

Unrecognized method, property, or field 'updateGraph' for class 'app1'.

Your updateGraph function is nested inside your UIAxesButtonDown method. So it's not a method of the class. Move the updateGrap...

17 days ago | 0

Number of counts in matrix

Use histcounts with unique (or uniquetol) to generate the bins. You will need to add one more bin at the end since the last bin ...

17 days ago | 0

Download of addons & update are blocked by company firewall

I am not 100% certain but I believe Add-Ons Manager and the Update installer need to connect to the same servers as the MathWork...

19 days ago | 0

Parse error at x

If all of the code you posted is in the same file, the line where you define the initial value occurs after the end keyword that...

19 days ago | 1

Generate 3D histogram while capping the height of bars

Rather than trying to make hist3 or histogram2 truncate the bins, consider using zlim to control the limits of the Z axis. x = ...

19 days ago | 0

Drawing polygons from vertex coordinates

See the polyshape function. If you're hoping MATLAB will automatically "figure out" what the polygons should be from your scatt...

20 days ago | 1