結果:

Starting in MATLAB R2021a, name-value arguments have a new optional syntax!

A property name can be paired with its value by an equal sign and the property name is not enclosed in quotes.

Compare the comma-separated name,value syntax to the new equal-sign syntax, either of which can be used in >=r2021a:

• plot(x, y, "b-", "LineWidth", 2)
• plot(x, y, "b-", LineWidth=2)

It comes with some limitations:

1. It's recommended to use only one syntax in a function call but if you're feeling rebellious and want to mix the syntaxes, all of the name=value arguments must appear after the comma-separated name,value arguments.
2. Like the comma-separated name,value arguments, the name=value arguments must appear after positional arguments.
3. Name=value pairs must be used directly in function calls and cannot be wrapped in cell arrays or additional parentheses.

Some other notes:

1. The property names are not case-sensitive so color='r' and Color='r' are both supported.
2. Partial name matches are also supported. plot(1:5, LineW=4)

The new syntax is helpful in distinguishing property names from property values in long lists of name-value arguments within the same line.

For example, compare the following 2 lines:

h = uicontrol(hfig, "Style", "checkbox", "String", "Long", "Units", "Normalize", "Tag", "chkBox1")

h = uicontrol(hfig,  Style="checkbox",    String="Long",    Units="Normalize",    Tag="chkBox1")

Here's another side-by-side comparison of the two syntaxes. See the attached mlx file for the full code and all content of this Community Highlight.

tiledlayout, introduced in MATLAB R2019b, offers a flexible way to add subplots, or tiles, to a figure.

Reviewing two changes to tiledlayout in MATLAB R2021a

1. The new TileIndexing property
2. Changes to TileSpacing and Padding properties

1) TileIndexing

By default, axes within a tiled layout are created from left to right, top to bottom, but sometimes it's better to organize plots column-wise from top to bottom and then left to right. Starting in r2021a, the TileIndexing property of tiledlayout specifies the direction of flow when adding new tiles.

tiledlayout(__,'TileIndexing','rowmajor') creates tiles by row (default).

tiledlayout(__,'TileIndexing','columnmajor') creates tiles by column.

.

2) TileSpacing & Padding changes

Some changes have been made to the spacing properties of tiles created by tiledlayout.

TileSpacing: sets the spacing between tiles.

• "loose" is the new default and replaces "normal" which is no longer recommended but is still accepted.
• "tight" replaces "none" and brings the tiles closer together still leaving space for axis ticks and labels.
• "none" results in tile borders touching, following the true meaning of none.
• "compact" is unchanged and has slightly more space between tiles than "tight".

Padding: sets the spacing of the figure margins.

• "loose" is the new default and replaces "normal" which is no longer recommended but is still accepted.
• "tight" replaces "none" and reduces the figure margins. "none" is no longer recommended but is still accepted.
• "compact" is unchanged and adds slightly more marginal space than "tight".
• Reducing the figure margins to a true none is still not an option.

The release notes show a comparison of these properties between r2020b and r2021a.

Here's what the new TileSpacing options (left column of figures below) and Padding options (right column) look like in R2021a. Spacing properties are written in the figure names.

.

And here's a grid of all 12 combinations of the 4 TileSpacing options and 3 Padding options in R2021a.

.

Code used to generate these figures

%% Animate the RowMajor and ColumnMajor indexing with colored tiles 
fig1 = figure('position',[200 200 560 420]); 
tlo1 = tiledlayout(fig1, 3, 3, 'TileIndexing','rowmajor');
title(tlo1, 'RowMajor indexing')

fig2 = figure('position',[760 200 560 420]); 
tlo2 = tiledlayout(fig2, 3, 3, 'TileIndexing','columnmajor');
title(tlo2, 'ColumnMajor indexing')

colors = jet(9);
drawnow()

for i = 1:9
    ax = nexttile(tlo1);
    ax.Color = colors(i,:);
    text(ax, .5, .5, num2str(i), 'Horiz','Cent','Vert','Mid','Fontsize',24)

      ax = nexttile(tlo2);
      ax.Color = colors(i,:);
      text(ax, .5, .5, num2str(i), 'Horiz','Cent','Vert','Mid','Fontsize',24)

      drawnow
      pause(.3)
  end

%% Show TileSpacing options
tileSpacing = ["loose","compact","tight","none"];
figHeight = 140;  % unit: pixels
figPosY = fliplr(50 : figHeight+32 : (figHeight+30)*numel(tileSpacing)); 

for i = 1:numel(tileSpacing)
    uif = uifigure('Units','Pixels','Position', [150 figPosY(i) 580 figHeight], ...
        'Name', ['TileSpacing: ', tileSpacing{i}]);
    tlo = tiledlayout(uif,1,3,'TileSpacing',tileSpacing(i)); 
    h = arrayfun(@(i)nexttile(tlo), 1:tlo.GridSize(2));
    box(h,'on')
    drawnow()
end

%% Show Padding options
padding = ["loose","compact","tight"];
for i = 1:numel(padding)
    uif = uifigure('Units','Pixels','Position', [732 figPosY(i) 580 figHeight], ...
        'Name', ['Padding: ', padding{i}]);
    tlo = tiledlayout(uif,1,3,'Padding',padding(i)); 
    h = arrayfun(@(i)nexttile(tlo), 1:tlo.GridSize(2));
    box(h,'on')
    drawnow()
end

%% Show all combinations of TileSpacing and Padding options
tileSpacing = ["loose","compact","tight","none"];
padding = ["loose","compact","tight"];
[tsIdx, padIdx] = meshgrid(1:numel(tileSpacing), 1:numel(padding));
figSize = [320 220]; % width, height (pixels)
figPosX = 150 + (figSize(1)+2)*(0:numel(tileSpacing)-1); 
figPosY = 50 + (figSize(2)+32)*(0:numel(padding)-1);
[figX, figY] = meshgrid(figPosX, fliplr(figPosY));
for i = 1:numel(padIdx)
    uif = uifigure('Units','pixels','Position',[figX(i), figY(i), figSize], ...
        'name', ['TS: ', tileSpacing{tsIdx(i)}, ', Pad: ', padding{padIdx(i)}]);
    tlo = tiledlayout(uif,2,2,'TileSpacing',tileSpacing(tsIdx(i)),'Padding',padding(padIdx(i))); 
    h = arrayfun(@(i)nexttile(tlo), 1:prod(tlo.GridSize));
    box(h,'on')
    drawnow()
end

let me invite you to distant Second international conference "MATLAB and computer calculations in education, science and engineering" April 26 – 29, 2021 р., Kyiv"

First communication

It is impossible to imagine recent science and engineering without mathematical packages like MATLAB, MathCAD, Mathematica, Maple etc. However, they have not been sufficiently used in education yet. To improve the situation we manage these conferences. This will be the Second conference in Ukraine. The First was carried out in May 2019. Its results may be seen here. Unfortunately, it should be carried out remotely this time. However, it is to happen to have the tradition saved!

Scientists, engineers, educators from universities and high schools are welcome! Regretfully, we need to restrict the scope of topics to be considered this time. They are to be associated with education in university or school, methodology of mathematical package application, teaching disciplines with them. Variety of problems we see in such a way this time:

Problems and sections:  MATLAB and computer use in universities  MATLAB and computer use and computer use in high school

Conference will be held remotely under supervision of National aviation university (Kyiv). Like last time, (remote) master classes will be carried out to, from our point, to facilitate MATLAB use for beginners in education. To facilitate remote participation of foreign guests, two kinds of sessions will be managed: Morning sections, 10 a.m. – 15 p.m. Kyiv’ time will use Ukrainian and Russian languages. Evening sections, 18 p.m. -:- 21 p.m. Kyiv’ time but 10 a.m. – 1 p.m. in San Francisco will use English, for participants from Europe and USA.

Organizational Committee and rules for Abstracts may be seen here, or in department site or asked for per e-mail Ye_Gayev@i.ua and YevgenyAlGayev@gmail.com

Important dates Till April 10, 2021 – registration via form or directly via above addresses. Till April 20, 2021 р. – accepting Abstracts, 4 pages prepared on rules. Opening the conference April 26, 2021. Conference days 26 – 28, April 2021. Book of Abstracts will be placed in the Internet and in https://www.academia.edu/; DOI will supplement them.

It is important that three master-classes are to be carried out in Saturday and Sunday, April 24 and 25. Their topics are:

1. Prof. Yevgeny Gayev (NAU) «Algorithms that inspire to education»; 2. Prof. Sergii Iglin (Kharkov) «Heat Transfer problems with MATLAB»; 3. Prof. Sergey Sylantyev (Kyiv Nat. univ.) «AWS Cloud Services and Cloud Calculation».

Potential participants are kindly asked to register as soon as possible for enabling our next management steps!

Did you know you can use most emoticons in text objects?

Most emoticons are just unicode characters. Using them as characters in Matlab is as simple as finding their numeric representation and then converting the numeric value back to character. Not all emoticons are convertible in Matlab.

Here's a secret message with emoticons. Use char(x) to decode it.

x = [79 77 71 33 32 55357 56878 32 104 97 118 101 32 121 111 ...
    117 32 117 112 100 97 116 101 100 32 116 111 32 77 97 116 ...
    108 97 98 32 55358 56595 32 114 50 48 50 49 97 32 121 101 116 32 8265];

Happy St. Patrick's Day!

fig = figure('MenuBar','none','Color', [0 .62 .376]);  % Shamrock green
ax = axes(fig,'Units','Normalized','Position',[0 0 1 1]);
axis(ax,'off')
axis(ax,'equal')
hold(ax,'on')
xlim(ax,[-1,1]); ylim(ax,[-1,1])
text(ax, 0, 0, char(9752), 'VerticalAlignment','middle','HorizontalAlignment','center','FontSize', 200)
str = num2cell('Happy St Patrick''s day!');
th = linspace(-pi/2,pi/2,numel(str)); 
txtHandle = text(ax,sin(th)*.8, cos(th)*.8, str, 'VerticalAlignment','middle','HorizontalAlignment','center','FontSize', 25);
set(txtHandle,{'rotation'}, num2cell(rad2deg(-th')))
thr = 0.017;
rotateCCW = @(xyz)([cos(thr) -sin(thr) 0; sin(thr), cos(thr), 0; 0 0 1]*xyz.').';
while all(isvalid(txtHandle))
    newposition = rotateCCW(vertcat(txtHandle.Position)); 
    set(txtHandle,{'position'}, mat2cell(newposition,ones(numel(txtHandle),1),3), ...
        {'rotation'}, num2cell([txtHandle.Rotation].'+thr*180/pi))
    drawnow()
end

We've all been there. You've got some kind of output that displays perfectly in the command window and you just want to capture that display as a string so you can use it again somewhere else. Maybe it's a multidimensional array, a table, a structure, or a fit object that perfectly displays the information you need in a neat and tidy format but when you try to recreate the display in a string variable it's like reconstructing the Taj Mahal out of legos.

Enter Matlab r2021a > formattedDisplayText()

Use str=formattedDisplayText(var) the same way you use disp(var) except instead of displaying the output, it's stored as a string as it would appear in the command window.

Additional name-value pairs allow you to

• Specify a numeric format
• Specify loose|compact line spacing
• Display true|false instead of 1|0 for logical values
• Include or suppress markup formatting that may appear in the display such as the bold headers in tables.

Demo: Record the input table and results of a polynomial curve fit

load census
[fitobj, gof] = fit(cdate, pop, 'poly3', 'normalize', 'on')

Results printed to the command window:

fitobj = 
     Linear model Poly3:
     fitobj(x) = p1*x^3 + p2*x^2 + p3*x + p4
       where x is normalized by mean 1890 and std 62.05
     Coefficients (with 95% confidence bounds):
       p1 =       0.921  (-0.9743, 2.816)
       p2 =       25.18  (23.57, 26.79)
       p3 =       73.86  (70.33, 77.39)
       p4 =       61.74  (59.69, 63.8)

gof = 
  struct with fields:

             sse: 149.77
         rsquare: 0.99879
             dfe: 17
      adjrsquare: 0.99857
            rmse: 2.9682

Capture the input table, the printed fit object, and goodness-of-fit structure as strings:

rawDataStr = formattedDisplayText(table(cdate,pop),'SuppressMarkup',true)
fitStr = formattedDisplayText(fitobj)
gofStr = formattedDisplayText(gof)

Display the strings:

rawDataStr = 
    "    cdate     pop 
         _____    _____
         1790       3.9
         1800       5.3
         1810       7.2
         1820       9.6
         1830      12.9
         1840      17.1
         1850      23.1
         1860      31.4
         1870      38.6
         1880      50.2
         1890      62.9
         1900        76
         1910        92
         1920     105.7
         1930     122.8
         1940     131.7
         1950     150.7
         1960       179
         1970       205
         1980     226.5
         1990     248.7
     "

fitStr = 
    "     Linear model Poly3:
          ary(x) = p1*x^3 + p2*x^2 + p3*x + p4
            where x is normalized by mean 1890 and std 62.05
          Coefficients (with 95% confidence bounds):
            p1 =       0.921  (-0.9743, 2.816)
            p2 =       25.18  (23.57, 26.79)
            p3 =       73.86  (70.33, 77.39)
            p4 =       61.74  (59.69, 63.8)
     "

gofStr = 
    "           sse: 149.77
            rsquare: 0.99879
                dfe: 17
         adjrsquare: 0.99857
               rmse: 2.9682
     "

Combine the strings into a single string and write it to a text file in your temp directory:

txt =  strjoin([rawDataStr; fitStr; gofStr],[newline newline]);
file = fullfile(tempdir,'results.txt');
fid = fopen(file,'w+');
cleanup = onCleanup(@()fclose(fid)); 
fprintf(fid, '%s', txt);
clear cleanup

Open results.txt.

winopen(file) % for Windows platforms

Hi All,

Quick question regarding deriving PM flux linkage [Wb] from a torque constant estimated from data on a PMLSM.

I have an estimated torque constant Kt [N/A], which is from experimental test data. I will now parameterising my Simscape PMLSM block from this torque constant.

The literature seems confusing, to derive PM flux linkage [Wb] from the experimental torque contant do i include the (3/2) constant. Some examples include the constant and some omit, which one of the following is preferred for deriving the PM flux linkage?

Thanks

Patrick

Hi, MathWorks / MATLAB / Simulink community! I have recently started working my way through the book mentioned in the topic, and I am wondering if anybody out there would be interested and have time to help me review some of my work on the exercises. Specifically, I'm currently working "Exercise 7.9 - Challenge: Design of a Type 2 PLL" and I am not convinced that my implementation is correct, but I'm having some trouble with debugging.

Is anyone interested and have time to review my implementation and give some feedback? I'd definitely appreciate it.

Thanks!

Shaun Lippy Middleburg, VA, USA

ASME will be hosting a four-part conversation series from March 22-25, that will educate and equip mechanical engineers with workforce strategies. The series will bring together leaders and industry experts in education to explore which new skills will be taught to young engineers, what training mid-career engineers need in order to return to work as the pandemic subsides, and how much more can be done to confront the labor and skills gap in 2021 and beyond.

I was honored to be asked to participate in the first panel discussion along with distinguished faculty from MIT and the University of Colorado Boulder. I would encourage all of our customers involved in online teaching and learning to attend. More details on the panel discussion that features MathWorks response to COVID-19 are below:

The Evolution of Engineering Education Post-COVID-19 (March 22): The transition to remote learning was a shock for many universities and colleges across the country. Professors had to transform their in-person lecture into an engaging online class, and students had to take on more self-learning responsibilities. What impact will this change in teaching have on the future of education? This conversation will focus on the shift to online education at universities, the digital engineering skills students will need to learn, and how academia and industry can work together to prepare the young engineers entering the workforce.

The Evolution of Engineering Education Post-COVID-19 : https://app.webinar.net/vlOW9kK90wm?mcc=EDIT

I just started my MPhil in power systems and we are doing load flow analysis. I am completely lost throughout the gauss seidel and newton Raphson methods using MatLab. can I get help, please?

This is a great presentation from 2 professors introducing how they use MATLAB in their physics courses. MATLAB Grader and Live Scripts are discussed in detail.

YouTube Video

Here is the abstract:

-----

Guest Presenters: Michele McColgan, Siena College and Duncan Carlsmith, UW Madison

The meeting will start with short presentations, and then we'll have time for questions and discussion in a colloquial setting. The presenters use MATLAB in their courses, and this meeting will provide a good opportunity to see the functionality that MATLAB affords. However, the presenters' approach to integrating computation is relevant generally; thus, this meeting should be of great interest, even if you are not a MATLAB user.

-----

Webinar from PICUP .

Prof. Duarte Antunes from Eindhoven University of Technology explains how he's been using MATLAB live scripts for teaching an online "Optimal Control and Dynamic Programming" course.

https://www.mathworks.com/company/newsletters/articles/using-matlab-live-scripts-to-teach-optimal-control-and-dynamic-programming-online.html

WiDS Datathon 2021 is going on right now. The focus of the Datathon this year is "on creating models to classify whether patients have been diagnosed with a certain type of diabetes." You can register and participate until March 1.

Also, take a look at this blog post on the MATLAB benchmark code for this datathon.

MATLAB Benchmark Code for WiDS Datathon 2021

There are also various online challenges by MathWorks that students may be interested. Here are the winners from last year's Simulink Student Challenge. There was also a MATLAB Online Live Editor Challenge a couple of years ago.

Hello , I wonder how to determine continous or discrete time modelling.For example if I want to run my model in MCU in this case discrete model is suitable?I am a bit confused

MATLAB Answers will now properly handle the use of the '*@*' character when you want to get someone's attention. This behavior is commonly referred to as 'mentioning' or 'tagging' someone and is a feature found in most communication apps.

Why we are doing this

To help with communication and potentially speed up conversations. Also, it turns out many of you have been typing the @ character in Answers already, even though the MATLAB Answers site didn't behave in the expected way.

How it works

Once you type the @ character a popup will appear listing the community members already in the Q/A thread, as you keep typing the list will expand to include members not in the thread. A mentioned user will receive a notification when the question/answer/comment is posted. Each mention in the Q/A thread will have a new visual style and link to the user profile for that community member.

If you don't want to get 'mentioned' you can turn off the setting in your communication preferences located on your profile page .

We hope you will find this feature helpful and as always please reply with any feedback you may have.

We have created a new community for users of ThingSpeak. This new community is for students, researchers, and engineers looking to use MATLAB, Simulink, and ThingSpeak for Internet of Things applications. You can find the latest ThingSpeak news, tutorials to jump-start your next IoT project, and a forum to engage in a discussion on your latest cloud-based project. You can see answers to problems other users have solved and share how you solved a problem.

Christopher Stapels will be moderating the new ThingSpeak community .

We encourage you to visit the new community and share best practices, examples, and ask questions.

Here's an example of virtualizing a lab course.

https://www.mathworks.com/company/newsletters/articles/virtualizing-electrical-engineering-teaching-labs.html

MathWorks is please to offer a new training course, Power Electronics Control Design with Simulink and Simscape.

This one-day course focuses on modeling and controlling power electronic systems in the Simulink® environment using Simscape Electrical™. Topics include:

• Modeling direct current (dc) power electronic components
• Controlling the level of fidelity in a model
• Developing controls for power electronics
• Modeling three-phase alternating current (ac) power electronic components
• Controlling power electronics for motor drive applications

Ameer Hamza had a great 2020 and has been awarded the coveted MOST ACCEPTED answers badge for all his contributions in MATLAB Answers this past year. Ameer joins Walter Roberson and Image Analyst in receiving this award going all the way back to 2012!

There are 10 community members who have achieved the Top Downloads badge for their popular File Exchange submissions in 2020. Do you recognize any of these names? There's a good chance you've used one or more of their toolboxes or scripts in your work if you're a frequent visitor to File Exchange, if you're not you might want to check out what they've posted, it may save you a lot of time writing your own code.

--------------------- Top Downloads Badge Winners -----------------

• PIRC
• Scott Lowe
• Yair Altman
• Dr. Siva Malla
• Chad Greene
• Seyedali Mirjalili
• Giampiero Campa
• Rodney Tan
• John D'Errico
• Steve Miller

Congratulations to all these winners and a giant THANK YOU for all they've done this past year to help everyone in the MATLAB Central community!