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Image Analyst
Last activity on 24 Dec 2024 at 21:30

Smart MATLAB savvy dogs

Attaching the Photoshop file if you want to modify the caption.

cartoon

Adam Danz
Last activity on 20 Dec 2024 at 15:43

bubblechart + bar plot - graphics

Check out this 3D chart that won Visual Of The Year for 2024 by Visual Capitalist. It's a mashup between a 3D bubblechart and a categorical bar plot yet the only graphical components are the x-axis labels and the legend. Not only does it show relative proportions of material in a laptop but it also shows what the raw material looks like.

I love the idea of analog data visualization. I wonder if any readers have made a analog "chart".

Highlights

Chen Lin
Last activity on 20 Dec 2024 at 14:41

Update to the Machine Translation Feature on MATLAB Answers

We’d like to announce a change on the Machine Translation feature on MATLAB Answers.

When users are visiting our international domains (e.g. China or Japan), Answers provides the option to translate the content. Recently, we identified several security threats involving high-volume requests from certain IP addresses targeting our translation service.

As one of the countermeasures, we have now placed the Machine Translation feature behind a login requirement. While non-logged-in users will still see the 'Translate' button, it will be inactive (greyed out) until they log in.

We are actively collaborating with adjacent teams to develop solutions to better detect and block malicious requests.

Please let us know if you have any questions or concerns.

Peter Fryscak
Last activity on 24 Dec 2024 at 14:53

Tree topper: L-Shaped Membrane

What better way to add a little holiday magic than the L-shaped membrane atop your evergreen? My colleagues output the shape and then added some thickness and an interior cylinder in Blender. Then, the shape was exported to STL and 3D printed (in several pieces). Then glued, sanded, primed, sanded again and painted. If you like, the STL file is attached. Thank you to https://blogs.mathworks.com/community/2013/06/20/paul-prints-the-l-shaped-membrane/ and a tip of the hat to MATLAB Ornament. Happy Holidays!

Mike Croucher
Last activity on 18 Dec 2024 at 18:47

Deep learning (and traditional Machine Learning) online training updates

The MATLAB Online Training Suite has been updated in the areas of Deep Learning and traditional Machine Learning! These are great self-paced courses that can get you from zero to hero pretty quickly.

Deep Learning Onramp (Free to everyone!) has been updated to use the dlnetwork workflow, such as the trainnet function, which became the preferred method for creating and training deep networks in R2024a.

Machine Learning Onramp (Free to everyone) has been updated with the following enhancements:

Content streamlined to reduce the focus on data processing and feature extraction, and emphasize the machine learning workflow.
Course example simplified by using a sample of the original data.
Classification Learner used in the course where appropriate.

The rest of the updates are for subscribers to the full Online Training Suite

The Deep Learning Techniques in MATLAB for Image Applications learning path teaches skills to tackle a variety of image applications. It is made up of the following four short courses:

Two more deep learning short courses are also available:

The Machine Learning Techniques in MATLAB learning path helps learners build their traditional machine learning skill set:

Fernando Meo
Last activity on 19 Dec 2024 at 13:48

Solution to slow execution of "uigetfile" function with an enormous number of files in a folder

If you have a folder with an enormous number of files and want to use the uigetfile function to select specific files, you may have noticed a significant delay in displaying the file list.

Thanks to the assistance from MathWorks support, an interesting behavior was observed.

For example, if a folder such as Z:\Folder1\Folder2\data contains approximately 2 million files, and you attempt to use uigetfile to access files with a specific extension (e.g., *.ext), the following behavior occurs:

Method 1: This takes minutes to show me the list of all files

[FileName, PathName] = uigetfile('Z:\Folder1\Folder2\data\*.ext',  'File selection');

Method 2: This takes less than a second to display all files.

[FileName, PathName] = uigetfile('*.ext', 'File selection','Z:\Folder1\Folder2\data');

Method 3: This method also takes minutes to display the file list. What is intertesting is that this method is the same as Method 2, except that a file seperator "\" is added at the end of the folder string.

[FileName, PathName] = uigetfile('*.ext', 'File selection','Z:\Folder1\Folder2\data\');

I was informed that the Mathworks development team has been informed of this strange behaviour.

I am using 2023a, but think this should be the same for newer versions.

Fernando Meo
Last activity on 18 Dec 2024 at 16:27

Solution to slow execution of "uigetfile" function with an enormous number of files in a folder

This post is more of a "tips and tricks" guide than a question.

If you have a folder with an enormous number of files and want to use the uigetfile function to select specific files, you may have noticed a significant delay in displaying the file list.

Thanks to the assistance from MathWorks support, an interesting behavior was observed.

Method 1: This takes minutes to show me the list of all files

[FileName, PathName] = uigetfile('Z:\Folder1\Folder2\data\*.ext',  'File selection');

Method 2: This takes less than a second to display all files.

[FileName, PathName] = uigetfile('*.ext', 'File selection','Z:\Folder1\Folder2\data');

[FileName, PathName] = uigetfile('*.ext', 'File selection','Z:\Folder1\Folder2\data\');

I was informed that the Mathworks development team has been informed of this strange behaviour.

I am using 2023a, but think this should be the same for newer versions.

Hannah
Last activity on 19 Dec 2024 at 1:20

Students! What was your favorite MATLAB assignment/project?

I'm beginning this MATLAB-based numerical methods class, and as I was thinking back to my previous MATLAB/Simulink classes, I definitely remember some projects more fondly than others. One of my most memorable was where I had to use MATLAB to analyze electrocardiogram (ECG) peaks. What about you guys? What are some of the best (or worst 🤭) MATLAB projects or assignments you've been given in the past?

Zhaoxu Liu / slandarer
Last activity on 16 Dec 2024 at 16:49

Christmas Tree for Matlaber : Rotating With Falling Snowflakes

Christmas is coming, here are two dynamic Christmas tree drawing codes:

Crystal XMas Tree

function XmasTree2024_1
fig = figure('Units','normalized', 'Position',[.1,.1,.5,.8],...
    'Color',[0,9,33]/255, 'UserData',40 + [60,65,75,72,0,59,64,57,74,0,63,59,57,0,1,6,45,75,61,74,28,57,76,57,1,1]);
axes('Parent',fig, 'Position',[0,-1/6,1,1+1/3], 'UserData',97 + [18,11,0,13,3,0,17,4,17],...
      'XLim',[-1.5,1.5], 'YLim',[-1.5,1.5], 'ZLim',[-.2,3.8], 'DataAspectRatio', [1,1,1], 'NextPlot','add',...
      'Projection','perspective', 'Color',[0,9,33]/255, 'XColor','none', 'YColor','none', 'ZColor','none')
%% Draw Christmas tree
F = [1,3,4;1,4,5;1,5,6;1,6,3;...
    2,3,4;2,4,5;2,5,6;2,6,3];
dP = @(V) patch('Faces',F, 'Vertices',V, 'FaceColor',[0 71 177]./255,...
    'FaceAlpha',rand(1).*0.2+0.1, 'EdgeColor',[0 71 177]./255.*0.8,...
    'EdgeAlpha',0.6, 'LineWidth',0.5, 'EdgeLighting','gouraud', 'SpecularStrength',0.3);
r = .1; h = .8; 
V0 = [0,0,0; 0,0,1; 0,r,h; r,0,h; 0,-r,h; -r,0,h];
% Rotation matrix
Rx = @(V, theta) V*[1 0 0; 0 cos(theta) sin(theta); 0 -sin(theta) cos(theta)];
Rz = @(V, theta) V*[cos(theta) sin(theta) 0;-sin(theta) cos(theta) 0; 0 0 1];
N = 180; Vn = zeros(N, 3); eval(char(fig.UserData))
for i = 1:N
    tV = Rz(Rx(V0.*(1.2 - .8.*i./N + rand(1).*.1./i^(1/5)), pi/3.*(1 - .6.*i./N)), i.*pi/8.1 + .001.*i.^2) + [0,0,.016.*i];
    dP(tV); Vn(i,:) = tV(2,:);
end
scatter3(Vn(:,1).*1.02,Vn(:,2).*1.02,Vn(:,3).*1.01, 30, 'w', 'Marker','*', 'MarkerEdgeAlpha',.5)
%% Draw Star of Bethlehem
w = .3; R = .62; r = .4; T = (1/8:1/8:(2 - 1/8)).'.*pi;
V8 = [ 0, 0, w;  0, 0,-w;
       1, 0, 0;  0, 1, 0; -1, 0, 0;  0,-1,0;
       R, R, 0; -R, R, 0; -R,-R, 0;  R,-R,0;
       cos(T).*r, sin(T).*r, T.*0];
F8 = [1,3,25; 1,3,11; 2,3,25; 2,3,11; 1,7,11; 1,7,13; 2,7,11; 2,7,13;
      1,4,13; 1,4,15; 2,4,13; 2,4,15; 1,8,15; 1,8,17; 2,8,15; 2,8,17;
      1,5,17; 1,5,19; 2,5,17; 2,5,19; 1,9,19; 1,9,21; 2,9,19; 2,9,21;
      1,6,21; 1,6,23; 2,6,21; 2,6,23; 1,10,23; 1,10,25; 2,10,23; 2,10,25];
V8 = Rx(V8.*.3, pi/2) + [0,0,3.5];
patch('Faces',F8, 'Vertices',V8, 'FaceColor',[255,223,153]./255,...
      'EdgeColor',[255,223,153]./255, 'FaceAlpha', .2)
%% Draw snow
sXYZ = rand(200,3).*[4,4,5] - [2,2,0];
sHdl1 = plot3(sXYZ(1:90,1),sXYZ(1:90,2),sXYZ(1:90,3), '*', 'Color',[.8,.8,.8]);
sHdl2 = plot3(sXYZ(91:200,1),sXYZ(91:200,2),sXYZ(91:200,3), '.', 'Color',[.6,.6,.6]);
annotation(fig,'textbox',[0,.05,1,.09], 'Color',[1 1 1], 'String','Merry Christmas Matlaber',...
    'HorizontalAlignment','center', 'FontWeight','bold', 'FontSize',48,...
    'FontName','Times New Roman', 'FontAngle','italic', 'FitBoxToText','off','EdgeColor','none');
% Rotate the Christmas tree and let the snow fall
for i=1:1e8
    sXYZ(:,3) = sXYZ(:,3) - [.05.*ones(90,1); .06.*ones(110,1)];
    sXYZ(sXYZ(:,3)<0, 3) = sXYZ(sXYZ(:,3) < 0, 3) + 5;
    sHdl1.ZData = sXYZ(1:90,3); sHdl2.ZData = sXYZ(91:200,3);
    view([i,30]); drawnow; pause(.05)
end
end

Curved XMas Tree

function XmasTree2024_2
fig = figure('Units','normalized', 'Position',[.1,.1,.5,.8],...
    'Color',[0,9,33]/255, 'UserData',40 + [60,65,75,72,0,59,64,57,74,0,63,59,57,0,1,6,45,75,61,74,28,57,76,57,1,1]);
axes('Parent',fig, 'Position',[0,-1/6,1,1+1/3], 'UserData',97 + [18,11,0,13,3,0,17,4,17],...
      'XLim',[-6,6], 'YLim',[-6,6], 'ZLim',[-16, 1], 'DataAspectRatio', [1,1,1], 'NextPlot','add',...
      'Projection','perspective', 'Color',[0,9,33]/255, 'XColor','none', 'YColor','none', 'ZColor','none')
%% Draw Christmas tree
[X,T] = meshgrid(.4:.1:1, 0:pi/50:2*pi);
XM = 1 + sin(8.*T).*.05;
X = X.*XM; R = X.^(3).*(.5 + sin(8.*T).*.02);
dF = @(R, T, X) surf(R.*cos(T), R.*sin(T), -X, 'EdgeColor',[20,107,58]./255,...
    'FaceColor', [20,107,58]./255, 'FaceAlpha',.2, 'LineWidth',1);
CList = [254,103,110; 255,191,115; 57,120,164]./255;
for i = 1:5
    tR = R.*(2 + i); tT = T+i; tX = X.*(2 + i) + i;
    SFHdl = dF(tR, tT, tX);
    [~, ind] = sort(SFHdl.ZData(:)); ind = ind(1:8);
    C = CList(randi([1,size(CList,1)], [8,1]), :);
    scatter3(tR(ind).*cos(tT(ind)), tR(ind).*sin(tT(ind)), -tX(ind), 120, 'filled',...
        'CData', C, 'MarkerEdgeColor','none', 'MarkerFaceAlpha',.3)
    scatter3(tR(ind).*cos(tT(ind)), tR(ind).*sin(tT(ind)), -tX(ind), 60, 'filled', 'CData', C)
end
%% Draw Star of Bethlehem
Rx = @(V, theta) V*[1 0 0; 0 cos(theta) sin(theta); 0 -sin(theta) cos(theta)];
% Rz = @(V, theta) V*[cos(theta) sin(theta) 0;-sin(theta) cos(theta) 0; 0 0 1];
w = .3; R = .62; r = .4; T = (1/8:1/8:(2 - 1/8)).'.*pi;
V8 = [ 0, 0, w;  0, 0,-w;
       1, 0, 0;  0, 1, 0; -1, 0, 0;  0,-1,0;
       R, R, 0; -R, R, 0; -R,-R, 0;  R,-R,0;
       cos(T).*r, sin(T).*r, T.*0];
F8 = [1,3,25; 1,3,11; 2,3,25; 2,3,11; 1,7,11; 1,7,13; 2,7,11; 2,7,13;
      1,4,13; 1,4,15; 2,4,13; 2,4,15; 1,8,15; 1,8,17; 2,8,15; 2,8,17;
      1,5,17; 1,5,19; 2,5,17; 2,5,19; 1,9,19; 1,9,21; 2,9,19; 2,9,21;
      1,6,21; 1,6,23; 2,6,21; 2,6,23; 1,10,23; 1,10,25; 2,10,23; 2,10,25];
V8 = Rx(V8.*.8, pi/2) + [0,0,-1.3];
patch('Faces',F8, 'Vertices',V8, 'FaceColor',[255,223,153]./255,...
      'EdgeColor',[255,223,153]./255, 'FaceAlpha', .2)
annotation(fig,'textbox',[0,.05,1,.09], 'Color',[1 1 1], 'String','Merry Christmas Matlaber',...
    'HorizontalAlignment','center', 'FontWeight','bold', 'FontSize',48,...
    'FontName','Times New Roman', 'FontAngle','italic', 'FitBoxToText','off','EdgeColor','none');
%% Draw snow
sXYZ = rand(200,3).*[12,12,17] - [6,6,16];
sHdl1 = plot3(sXYZ(1:90,1),sXYZ(1:90,2),sXYZ(1:90,3), '*', 'Color',[.8,.8,.8]);
sHdl2 = plot3(sXYZ(91:200,1),sXYZ(91:200,2),sXYZ(91:200,3), '.', 'Color',[.6,.6,.6]);
for i=1:1e8
    sXYZ(:,3) = sXYZ(:,3) - [.1.*ones(90,1); .12.*ones(110,1)];
    sXYZ(sXYZ(:,3)<-16, 3) = sXYZ(sXYZ(:,3) < -16, 3) + 17.5;
    sHdl1.ZData = sXYZ(1:90,3); sHdl2.ZData = sXYZ(91:200,3);
    view([i,30]); drawnow; pause(.05)
end
end

I wish all MATLABers a Merry Christmas in advance!

Off Topic

Audace NSHIMIRIMANA
Last activity on 10 Dec 2024 at 23:34

Improvement of Energy Management Strategy (EMS) of Plug In Hybrid Electric Vehicles (PHEV) Using Rule-based Control Strategy and Signal Processing / ITS

Watt's Up with Electric Vehicles?EV modeling Ecosystem (Eco-friendly Vehicles), V2V Communication and V2I communications thereby emitting zero Emissions to considerably reduce NOx ,Particulates matters,CO2 given that Combustion is always incomplete and will always be.

Reduction of gas emissions outside to the environment will improve human life span ,few epidemic diseases and will result in long life standard

Highlights

David
Last activity on 9 Dec 2024 at 20:01

MATLAB Answers Maintenance Today @1PM

We will be updating the MATLAB Answers infrastructure at 1PM EST today. We do not expect any disruption of service during this time. However, if you notice any issues, please be patient and try again later. Thank you for your understanding.

Hannah
Last activity on 16 Dec 2024 at 7:38

When upgrading to a new version of MATLAB, do you typically uninstall the previous version?

https://www.youtube.com/channel/UCfHL7p2iQg7MRAFkUIuTxuQ

Mike Croucher
Last activity on 6 Dec 2024 at 22:32

MATLAB en Español

Many of my best friends at MathWorks speak Spanish as their first language and we have a large community of Spanish-speaking users. You can see good evidence of this by checking out our relatively new Spanish YouTube channel which recently crossed the 10,000 subscriber mark

https://blogs.mathworks.com/matlab/2024/12/05/numpy-in-matlab/

Mike Croucher
Last activity on 13 Dec 2024 at 1:01

MATLAB and Numpy

I've always used MATLAB with other languages. In the early days, C and C++ via mex files were the most common ways I spliced two languages together. Other than that I've also used MATLAB with Java, Excel and even Fortran.

In more recent years, Python is the language I tend to use most alongside MATLAB and support for this combination is steadily improving. In my latest blog post, I show how easy it has become to use Python's Numpy with MATLAB.

Have you used this functionality much? If so, what for? How well did it work for you?

https://youtu.be/t4G6Tpl08Jc?si=7vPsrPJlRRht5MsN

David Ding
Last activity on 10 Dec 2024 at 19:51

Single Light Ray Refracting Inside a Raindrop

I am inspired by the latest video from YouTube science content creator Veritasium on his distinct yet thorough explanation on how rainbows work. In his video, he set up a glass sphere experiment representing how light rays would travel inside a raindrop that ultimately forms the rainbow. I highly recommend checking it out.

In the meantime, I created an interactive MATLAB App in MATLAB Online using App Designer to visualize the light paths going through a spherical raindrop with numerical calculations along the way. While I've seen many diagrams out there showing the light paths, I haven't found any doing calculations in each step. Hence I created an app in MATLAB to show the calculations along with the visualizations as one varies the position of the incoming light ray.

Demo video:

For more information about the app and how to open it and play around with it in MATLAB Online, please check out my blog article:

https://www.davidyding.com/navPages/Rainbow

https://blogs.mathworks.com/loren/2016/04/01/the-queens-matlab/?s_tid=srchtitle_site_search_4_rgb2gray

Image Analyst
Last activity on 5 Dec 2024 at 5:43

Difference between gray and grey

To convert a color image to grayscale, use rgb2gray, or is it rgb2grey?

Toshiaki Takeuchi
Last activity on 3 Dec 2024 at 22:30

Help improve MATLAB Accessibility

Our MathWorks Usability Team is working on an accessibility project and they want to interview people who use MATLAB and also have experience with screen readers.

If you fit the criteria and are interested, sign up here https://www.mathworks.com/products/usability.html?tfa_30=A11Y

Steve Eddins
Last activity on 3 Dec 2024 at 2:20

Evolution of arguments-block functionality

I wish I knew more about the intended evolution of the capabilities of the function arguments block. I love implementing function syntaxes using this relatively new form, but it doesn't yet handle some function syntax design patterns that I think are valuable and worth keeping.

For example, some functions take an input quantity that can something numeric, or it can be an option string that descriptively names a particular value of that quantity. One example is dateshift(t,"dayofweek",dow), where dow can be an integer from 1 to 7, or it can be one of the option strings "weekday" or "weekend".

Another example is Image Processing Toolbox that take a connectivity specifier as input. The function bwconncomp is one particular case. Connectivity can be specified using certain scalars, certain arrays, or the option string "maximal".

I think this is a worthwhile function design pattern, but I don't think the arguments block validation functionality supports it well (unless you use a lot of extra code that duplicates standard MATLAB behavior, which undermines the value of the arguments block).

I posted about this today over on my blog. See "Function Syntax Design Conundrum."

MathWorkers - believe me, I know that it is not in your DNA to discuss future features. But would anyone care to offer a hint about directions for the arguments block functionality?

(1) Ben Hayden: "When you are using matlab and you want to get the square root of the result of the most recent command line operation." — Bluesky

Mike Croucher
Last activity on 2 Dec 2024 at 23:15

An unintentional MATLAB meme

I enjoyed this post on BlueSky yesterday