Community Profile

photo

J. Alex Lee


Last seen: Today
109 total contributions since 2016

J. Alex Lee's Badges

  • 6 Month Streak
  • Revival Level 1
  • Knowledgeable Level 3
  • First Review
  • Solver
  • Thankful Level 1
  • First Answer

View details...

Contributions in
View by

Answered
how to use tensors
this is a bit imprecise, but if you mean "order 2 tensor", it can be represented as a 2D matrix. Order 3 tensor is then 3D matri...

1 day ago | 0

Answered
ode45 error rungg- kutta
your error is probably not with the ODE line, but actually running "Simulation", which you are not supplying any arguments to at...

15 days ago | 0

Answered
Solving second order PDE
Does this help: https://www.mathworks.com/help/matlab/ref/pdepe.html I believe that pdepe is available with base matlab. It ap...

19 days ago | 0

Answered
Saving multiple outputs from ODE45 with different dimensions?
I would use cells...also what's with the dual indexing? options can be defined outside since nothing is changing from iteration ...

25 days ago | 0

Answered
Increment a class property everytime calling a class method
subclass from the handle class (default is value class), and you can update properties of the instance without explicitly overwr...

26 days ago | 1

| accepted

Answered
How to plot values with different color with "if statement"
look at the documentation for the "scatter()" command. can you do what you want with that?

1 month ago | 0

Answered
App inside app question
If not more than 1 image needs to be displayed at once, maybe just save all the image data internally, have only one axes, and h...

1 month ago | 1

| accepted

Answered
Selection of data in timetable
Hmm, so the question is about periodic time ranges...there might be a better way, but maybe you can use "isbetween" on an auxili...

1 month ago | 0

Answered
How can i select cell from table in app designer?
The UITable has a callback for selection https://www.mathworks.com/help/matlab/ref/matlab.ui.control.tableappd-properties.html#...

1 month ago | 0

Answered
Reading data from ASCII file
It would have been helpful to know these things in advance (you hinted at the first, but say it explicitly) Data contains multi...

2 months ago | 0

Answered
Surface Fit over image
Here's my first pass thoughts: First steps: Obtain X and Y coordinates of your pixels ensure your pixel values are of type do...

2 months ago | 1

| accepted

Question


How to identify ui component classes that other ui components can be children of
I am trying to identify ui components like uipanels, uigridlayouts, uitabs, etc., that may contain other ui components as childr...

2 months ago | 1 answer | 0

1

answer

Answered
Plotting points in 3D with mesh
For just visualizing the chosen data in a surface, does this look like what you want? clc; close all; clear; N = 500; X...

3 months ago | 0

| accepted

Answered
How can I solve a partial derivative equation if it does not contain a time derivative in MATLAB?
If you mean by "no time variable" that your equation is elliptic in more than 1 independent variable, then unfortunately you'll ...

3 months ago | 0

| accepted

Answered
[App Designer] Get the object indentifier that triggered the callback
I think a cleaner way is to pass an identifier with the callback definition: ASpinner.ValueChangedFcn = @(evnt)app.VChanged(evn...

3 months ago | 0

Answered
Plotting a graphic output of an external function in APPDESIGNER, more specifically the uiaxes
If there is no way to activate a uiaxes programmatically, you can try to create a regular axes in app designer in the startupfcn...

3 months ago | 0

Answered
Roots of a two variables equation involving a numerical integration
Assuming x and y are scalars and there is a solution, use fsolve, not an optimization algorithm. You'll need initial guesses. Th...

3 months ago | 1

Answered
Accessing an element of an array using an array as its index.
Interesting...I guess your question title should be edited to "use array as subscripts into multidimensional array". I dug into ...

3 months ago | 0

| accepted

Answered
Struct to numeric variable
At the risk of having misunderstood: new_var = [structname.fieldname] This would work if you structname is a structure array 4...

3 months ago | 0

Answered
How can I specify the way components resize automatically in App Designer?
"uigridlayout" was introduced in 2018b, which may be helpful...It allows pretty sophisticated layouts, although it still seems b...

3 months ago | 1

Answered
How to add the value of the 3 highest elements automatically from a vector?
like this? [~,idx] = maxk(y,3) y(idx) = y(idx) + sx Are x1 and x2 irrelevant to your question?

4 months ago | 0

Answered
How to map a vector to a colourmap ?
A brute force way would be to interpolate...not sure if there's a better way x = % ... data vector indices = 0:255; xref = ...

4 months ago | 1

| accepted

Answered
Making a square figure with pcolor
Your coordinate grid matrices x and y are not "aligned" with the axes. You can see this if you just do plot3(x,y,zeros(size(x)...

4 months ago | 0

Answered
Getting Cell location of checkboxes on selection (UITable)
Is it as simple as defining a CellEditCallback?

4 months ago | 0

| accepted

Answered
Is there an automatic way to find the centre of this circularly-symmetric pattern?
This would be not at all efficient and maybe not robust, but you could pose a minimization problem: Find the coordinates (Xc,Yc...

4 months ago | 0

Answered
How can I create binEdges?
It looks like your problem is not with binning, but the fact that you have NaN's in your data. By the way if you have 2014b or ...

4 months ago | 0

| accepted

Answered
Extracting particular x and y data points from a figure
Thinking in terms of graphs is useful but only takes you so far. The point is how to think about the data and/or functions under...

4 months ago | 0

| accepted

Answered
Help in implementing ode45 in app designer
Static methods don't assume that the app is passed as the first argument, so remove "app" from the arg list methods (Static) ...

4 months ago | 0

Answered
Validate and get exact number of characters using the regular expression
Try out_str = regexp(str, '[A-Z]+-[0-9]{2}$', 'match');

4 months ago | 1

| accepted

Answered
How to initialize a new matrix of the same type as an existing variable?
I am not sure if this works for symbolic type, but you can initialize an array of arbitrary type by specifying the "last" elemen...

4 months ago | 0

Load more