結果:
I am very excited to share my new book "Data-driven method for dynamic systems" available through SIAM publishing: https://epubs.siam.org/doi/10.1137/1.9781611978162
This book brings together modern computational tools to provide an accurate understanding of dynamic data. The techniques build on pencil-and-paper mathematical techniques that go back decades and sometimes even centuries. The result is an introduction to state-of-the-art methods that complement, rather than replace, traditional analysis of time-dependent systems. One can find methods in this book that are not found in other books, as well as methods developed exclusively for the book itself. I also provide an example-driven exploration that is (hopefully) appealing to graduate students and researchers who are new to the subject.
Each and every example for the book can be reproduced using the code at this repo: https://github.com/jbramburger/DataDrivenDynSyst
Hope you like it!
Christmas season is underway at my house:
(Sorry - the ornament is not available at the MathWorks Merch Shop -- I made it with a 3-D printer.)
Hi everyone,
I am performing an optimization analysis using MATLAB's Genetic Algorithm (GA) to select design variables, which are then passed to ANSYS to calculate some structural properties. My goal is to find the global optimum, so I have set the population size to 100 × number of variables. While this ensures a broader search space and reduces the risk of getting stuck in local optima, it significantly increases the convergence time because finite element analysis (FEA) needs to be performed for each population member. The current setup takes about a week (or more) to converge, which is not feasible.
To address this, I plan to implement parallel computing for the GA. I need help with the following aspects:
- Parallel Implementation:On my local desktop, I have Number of workers: 6, which means I can evaluate 6 members of the population simultaneously. However, I want to make my code generic so that it automatically adjusts to the number of workers available on any machine. How can I achieve this in MATLAB?
- Improving Convergence Speed:Another approach I’ve come across is using the MigrationInterval and MigrationFractionoptions to divide the population into smaller "islands" that exchange solutions periodically. Would this approach be suitable in my case, and how can I implement it effectively?
- Objective Function Parallelization:Below is the current version of my objective function, which works without parallelization. It writes input variables to an ANSYS .inp file, runs the simulation, and reads results from a text file. How should I modify this function (if needed) to make it compatible with MATLAB’s parallel computing features?
function cost = simple_objective(x, L)
% Write input variables to the file
fid = fopen('Design_Variables.inp', 'w+'); % Ansys APDL reads this
fprintf(fid, 'H_head = %f\n', x(1));
fprintf(fid, 'R_top = %f\n', x(2));
fclose(fid);
% Set ANSYS and Run model
ansys_input = 'ANSYS_APDL.dat';
output_file = 'out_file.txt';
cmd = sprintf('SET KMP_STACKSIZE=15000k & "C:\\Program Files\\ANSYS Inc\\v232\\ansys\\bin\\winx64\\ANSYS232.exe" -b -i %s -o %s', ansys_input, output_file);
system(cmd);
% Remove file lock if it exists
if exist('file.lock', 'file')
delete('file.lock');
end
% Read results
fileID = fopen('PC1.txt', 'r');
load_multip = fscanf(fileID,'%f',[1,inf]);
fclose(fileID);
if load_multip == 0 % nondesignable geometry
cost = 1e9; % penalty
else
cost = -load_multip;
end
end
GA Options:
Here are the GA options I am currently using. Do I need to adjust these for parallelization or migration-based approaches?
“options = optimoptions("ga", ... 'OutputFcn',@SaveOut, ... 'Display', 'iter', ... 'PopulationSize', 200, ... 'Generations', 50, ... 'EliteCount', 2, ... 'CrossoverFraction', 0.98, ... 'TolFun', 1.0e-9, ... 'TolCon', 1.0e-9, ... 'StallTimeLimit', Inf, ... 'FitnessLimit', -Inf, ... 'PlotFcn',{@gaplotbestf,@gaplotstopping});”
I would greatly appreciate it if you could guide me on:
- How to enable and configure parallel computing for GA in MATLAB.
- Any adjustments required in the objective function for parallel execution.
- Whether migration-based GA (using MigrationInterval and MigrationFraction) is a good alternative in my case.
Thank you for your time and help!
So I made this.
clear
close all
clc
% inspired from: https://www.youtube.com/watch?v=3CuUmy7jX6k
%% user parameters
h = 768;
w = 1024;
N_snowflakes = 50;
%% set figure window
figure(NumberTitle="off", ...
name='Mat-snowfalling-lab (right click to stop)', ...
MenuBar="none")
ax = gca;
ax.XAxisLocation = 'origin';
ax.YAxisLocation = 'origin';
axis equal
axis([0, w, 0, h])
ax.Color = 'k';
ax.XAxis.Visible = 'off';
ax.YAxis.Visible = 'off';
ax.Position = [0, 0, 1, 1];
%% first snowflake
ht = gobjects(1, 1);
for i=1:length(ht)
ht(i) = hgtransform();
ht(i).UserData = snowflake_factory(h, w);
ht(i).Matrix(2, 4) = ht(i).UserData.y;
ht(i).Matrix(1, 4) = ht(i).UserData.x;
im = imagesc(ht(i), ht(i).UserData.img);
im.AlphaData = ht(i).UserData.alpha;
colormap gray
end
%% falling snowflake
tic;
while true
% add a snowflake every 0.3 seconds
if toc > 0.3
if length(ht) < N_snowflakes
ht = [ht; hgtransform()];
ht(end).UserData = snowflake_factory(h, w);
ht(end).Matrix(2, 4) = ht(end).UserData.y;
ht(end).Matrix(1, 4) = ht(end).UserData.x;
im = imagesc(ht(end), ht(end).UserData.img);
im.AlphaData = ht(end).UserData.alpha;
colormap gray
end
tic;
end
ax.CLim = [0, 0.0005]; % prevent from auto clim
% move snowflakes
for i = 1:length(ht)
ht(i).Matrix(2, 4) = ht(i).Matrix(2, 4) + ht(i).UserData.velocity;
end
if strcmp(get(gcf, 'SelectionType'), 'alt')
set(gcf, 'SelectionType', 'normal')
break
end
drawnow
% delete the snowflakes outside the window
for i = length(ht):-1:1
if ht(i).Matrix(2, 4) < -length(ht(i).Children.CData)
delete(ht(i))
ht(i) = [];
end
end
end
%% snowflake factory
function snowflake = snowflake_factory(h, w)
radius = round(rand*h/3 + 10);
sigma = radius/6;
snowflake.velocity = -rand*0.5 - 0.1;
snowflake.x = rand*w;
snowflake.y = h - radius/3;
snowflake.img = fspecial('gaussian', [radius, radius], sigma);
snowflake.alpha = snowflake.img/max(max(snowflake.img));
end
Hello,
I have a MATLAB App that has been devolped in the MATLAB App Designer. I have saved all of the apps properties when the user selects the save config menu option and saved it into a .mat file.
Now I want to be able to load this file and update the app to the properties saved in this file. Currently, the program will store the variables in the app structure, but will not update the app's UIFigure. If I save the the UIFigure itself the program will create a new UIFigure and the code in App Designer will no longer work. Hence, why I've added not to save the UIFigure.
if strcmp(propName, 'SuperMarioUIFigure')
continue;
end
Does anyone know how I can get the app structure to update the current UIFigure that App Designer is running?
Here is my current code.
% Menu selected function: SaveConfigMenu
function SaveConfigMenuSelected(app, event)
% Create a structure to hold all the properties of the app
config = struct();
% List all properties of the app
metaProps = properties(app);
% Loop through properties and store their values in structure
for i = 1:length(metaProps)
propName = metaProps{i};
if strcmp(propName, 'SuperMarioUIFigure')
continue;
end
try
config.(propName) = app.(propName);
catch
% Handle any properties that can't be saved
fprintf('Could not save property: %s\n', propName);
end
end
% Prompt user to specify a file to save the configuration
[file, path] = uiputfile('*.mat', 'Save Configuration As');
if isequal(file, 0) || isequal(path, 0)
return; % User cancelled
end
% Save the configuration structure to a file
save(fullfile(path, file), '-struct', 'config');
uialert(app.SuperMarioUIFigure, 'Configuration saved successfully!', 'Save Configuration');
end
% Menu selected function: LoadConfigMenu
function LoadConfigMenuSelected(app, event)
% Prompt user to select a configuration file
[file, path] = uigetfile('*.mat', 'Load Configuration');
if isequal(file, 0) || isequal(path, 0)
return; % User cancelled
end
% Load the configuration structure from the file
config = load(fullfile(path, file));
% List all properties of the app
metaProps = properties(app);
% Update app properties with values from the configuration file
for i = 1:length(metaProps)
propName = metaProps{i};
if isfield(config, propName)
try
app.(propName) = config.(propName);
catch ME
% Handle any properties that can't be updated
fprintf('Could not load property: %s. Error: %s\n', propName, ME.message);
end
end
end
% Display a success message
uialert(app.SuperMarioUIFigure, 'Configuration loaded successfully!', 'Load Configuration');
end
Thanks
Hello, I have a very simple Simulink program to control a servo with my Arduino. The problem is that I'm not getting a full range of the servo. I am using an Adafruit Motor Shield to drive the servo which is a cheap TowerPro. The range I'm getting is 0 to 70. I am using Matlab/Simulink 2019.
Any ideas what could be wrong?
Thank you
The expression for a zero-symmetric polyhedron is known, S={x:[1; 1]<=Ax<=[1; 1]}, where A=[0.5 0; -0.5 0; 0 0.25; 0 -0.25], can you use the polyhedron function to draw an image of the polyhedron, I hope you can write detailed code
Is it possible to differenciate the input, output and in-between wires by colors?
if app.LikeCheckBox.Value==true
app.EditField.Value='you Like our channal'
elseif app.LikeCheckBox.Value==true && app.ShareCheckBox.Value==true
app.EditField.Value='you liked and shared'
elseif app.ShareCheckBox.Value==true
app.EditField.Value='you Share our channal'
elseif app.ShareCheckBox.Value==true && app.SubscribeCheckBox.Value==true
app.EditField.Value='you shared and subscribed'
elseif app.SubscribeCheckBox.Value==true
app.EditField.Value='you Subscribed to our channal'
elseif app.LikeCheckBox.Value==true && app.SubscribeCheckBox.Value==true
app.EditField.Value='good job'
else app.EditField.Value='Choose on item'
app.EditField.HorizontalAlignment='center'
end
At the present time, the following problems are known in MATLAB Answers itself:
- Symbolic output is not displaying. The work-around is to disp(char(EXPRESSION)) or pretty(EXPRESSION)
- Symbolic preferences are sometimes set to non-defaults
I was curious to startup your new AI Chat playground.
The first screen that popped up made the statement:
"Please keep in mind that AI sometimes writes code and text that seems accurate, but isnt"
Can someone elaborate on what exactly this means with respect to your AI Chat playground integration with the Matlab tools?
Are there any accuracy metrics for this integration?
Just shared an amazing YouTube video that demonstrates a real-time PID position control system using MATLAB and Arduino.
When I am inputting data, I am trying to input an equation that I should result in multiple answers. The equation I am trying to do is an output in Kw, divided by a conversion percentage. That percentage ranges from 5-15. No matter what way I put this data in to the system, it kicks out a bunch of 0's and then one column of real numners. The data chart should be 5 columns wide and 11 rows down, but for some reason it is giving me excess columns. 
I don't like the change
16%
I really don't like the change
29%
I'm okay with the change
24%
I love the change
11%
I'm indifferent
11%
I want both the web & help browser
11%
38 票
We are thrilled to announce the grand prize winners of our MATLAB Shorts Mini Hack contest! This year, we invited the MATLAB Graphics and Charting team, the authors of the MATLAB functions used in every entry, to be our judges. After careful consideration, they have selected the top three winners:
Judge comments: Realism & detailed comments; wowed us with Manta Ray
2nd place – Jenny Bosten
Judge comments: Topical hacks : Auroras & Wind turbine; beautiful landscapes & nightscapes
3rd place - Vasilis Bellos
Judge comments: Nice algorithms & extra comments; can’t go wrong with Pumpkins
Judge comments: Impressive spring & cubes!
In addition, after validating the votes, we are pleased to announce the top 10 participants on the leaderboard:
Congratulations to all! Your creativity and skills have inspired many of us to explore and learn new skills, and make this contest a big success!
You can make a lot of interesting objects with matlab primitive shapes (e.g. "cylinder," "sphere," "ellipsoid") by beginning with some of the built-in Matlab primitives and simply applying deformations. The gif above demonstrates how the Manta animation was created using a cylinder as the primitive and successively applying deformations: (https://www.mathworks.com/matlabcentral/communitycontests/contests/8/entries/16252);
Similarly, last year a sphere was deformed to create a face in two of my submissions, for example, the profile in "waking":
You can piece-wise assemble images, but one of the advantages of creating objects with deformations is that you have a parametric representation of the surface. Creating a higher or lower polygon rendering of the surface is as simple as declaring the number of faces in the orignal primitive. For example here is the scene in "snowfall" using sphere with different numbers of input faces:
sphere(100)
sphere(500)
High poly models aren't always better. Low-polygon shapes can sometimes add a little distance from that low point in the uncanny valley.
Next week is MATLAB EXPO week and it will be the first one that I'm presenting at! I'll be giving two presentations, both of which are related to the intersection of MATLAB and open source software.
- Open Source Software and MATLAB: Principles, Practices, and Python Along with MathWorks' Heather Gorr. We we discuss three different types of open source software with repsect to their relationship to MATLAB
- The CLASSIX Story: Developing the Same Algorithm in MATLAB and Python Simultaneously A collaboration with Prof. Stefan Guettel from University of Manchester. Developing his clustering algorithm, CLASSIX, in both Python and MATLAB simulatenously helped provide insights that made the final code better than if just one language was used.
There are a ton of other great talks too. Come join us! (It's free!) MATLAB EXPO 2024
Hi MATLAB Central community! 👋
I’m currently working on a project where I’m integrating MATLAB analytics into a mobile app, mainly to handle data-heavy tasks like processing sensor data and running predictive models. The app is built for Android, and while it’s not entirely MATLAB-based, I use MATLAB for a lot of data preprocessing and model training.
I wanted to reach out and see if anyone else here has experience with using MATLAB for similar mobile or embedded applications. Here are a few areas I’m focusing on:1. Optimizing MATLAB Code for Mobile Compatibility
I’ve found that some MATLAB functions work perfectly on desktop but may run slower or encounter limitations on mobile. I’ve tried using code generation and reducing function calls where possible, but I’m curious if anyone has other tips for optimizing MATLAB code for mobile environments?
2. Using MATLAB for Sensor Data Processing
I’m working with accelerometer and GPS data, and MATLAB has been great for preprocessing. However, I wonder if anyone has suggestions for handling large sensor datasets efficiently in MATLAB, especially if you've managed data in mobile contexts?
3. Integrating MATLAB Models into Mobile Apps
I’ve heard about using MATLAB Compiler SDK to integrate MATLAB algorithms into other environments. For those who have done this, what’s the best way to maintain performance without excessive computational strain on the device?
4. Data Visualization Tips
Has anyone had experience with mobile-friendly data visualizations using MATLAB? I’ve been using basic plots, but I’d love to know if there are any resources or toolboxes that make it easier to create lightweight, interactive visuals for mobile.
If anyone here has tips, tools, or experiences with MATLAB in mobile development, I’d love to hear them! Thanks in advance for any advice you can share!
Dear MATLAB contest enthusiasts,
Welcome to the third installment of our interview series with top contest participants! This time we had the pleasure of talking to our all-time rock star – @Jenny Bosten. Every one of her entries is a masterpiece, demonstrating a deep understanding of the relationship between mathematics and aesthetics. Even Cleve Moler, the original author of MATLAB, is impressed and wrote in his blog: "Her code for Time Lapse of Lake View to the West shows she is also a wizard of coordinate systems and color maps."
you to read it to learn more about Jenny’s journey, her creative process, and her favorite entries.
Question: Who would you like to see featured in our next interview? Let us know your thoughts in the comments!
My favorite image processing book is The Image Processing Handbook by John Russ. It shows a wide variety of examples of algorithms from a wide variety of image sources and techniques. It's light on math so it's easy to read. You can find both hardcover and eBooks on Amazon.com Image Processing Handbook
There is also a Book by Steve Eddins, former leader of the image processing team at Mathworks. Has MATLAB code with it. Digital Image Processing Using MATLAB
You might also want to look at the free online book http://szeliski.org/Book/
