Matlab | those matlab tips you have to know (2)

1: Real time script control

Real time script should be used by most people , But there are not many people who should use real-time script controls , How to put it? , It should be a module that is more convenient to adjust parameters . Click the icon button to insert various types of controls ：

After inserting, double-click the control to set its properties ：

A few simple examples ( Because push can't display controls , Therefore, the code given is a control free version , Please add controls by yourself , Or download the network disk compressed package ：
【 link 】：https://pan.baidu.com/s/15JxprFG8B10DsocdwzqqLQ?pwd=slan
【 Extraction code 】：slan

Butterfly thread

a=3.5;
clc;cla;clf
x=linspace(0,2*pi,500);
hdl=polarplot(x,sin(x)+sin(a.*x).^3,'LineWidth',1.5);
ax=gca;ax.RTick=[];

Discolored rose

clc;cla;clf
CMAP="parula";
[x,t]=meshgrid((0:24)./24,(0:0.5:575)./575.*20.*pi+4*pi);
p=(pi/2)*exp(-t./(8*pi));
change=sin(15*t)/150;
u=1-(1-mod(3.6*t,2*pi)./pi).^4./2+change;
y=2*(x.^2-x).^2.*sin(p);
r=u.*(x.*sin(p)+y.*cos(p));
h=u.*(x.*cos(p)-y.*sin(p));
surface(r.*cos(t),r.*sin(t),h,'EdgeAlpha',0.1,...
    'EdgeColor',[0 0 0],'FaceColor','interp')
colormap(CMAP)
grid on
view(45,45)

Rotate polygon

lenRatio=0.19;
numEdge=7;
numPolygon=14;

clc;cla;clf
theta=linspace(0,2*pi,numEdge+1);
X=cos(theta);X(end)=[];
Y=sin(theta);Y(end)=[];

fill(X,Y,[0,0,0],'FaceColor','none');
hold on;
axis equal
axis([-1,1,-1,1])

for i=1:numPolygon
    tX=[X(2:end),X(1)];
    tY=[Y(2:end),Y(1)];
    X=(tX-X).*lenRatio+X;
    Y=(tY-Y).*lenRatio+Y;
    fill(X,Y,[0,0,0],'FaceColor','none');
end
hold off

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2: Translucent line chart

Line graph function on the official website plot The introduction tells us how to change the thickness , How to adjust the mark style , How to adjust the color , But it doesn't tell us how to set transparency , But in fact plot Of color The attribute looks like rgb value , In fact, it can be rgba value , We put the original rgb Change triples to quadruples to set transparency , for example ：

x=0:.1:4*pi;
hold on
plot(x,sin(x),'LineWidth',2,'Color',[1,0,0,0.5]) %  Red , transparent 50%
plot(x,cos(x),'LineWidth',2,'Color',[0,0,1,0.5]) %  Blue , transparent 50%

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3: MATLAB Bring your own color (lines)

The system comes with discrete colors , Various values on the official website ：

But there is actually a built-in function lines You can get these basic colors ： for example ：

lines(1)

lines(2)

ans =
0.0000 0.4470 0.7410

ans =
0.0000 0.4470 0.7410
0.8500 0.3250 0.0980

Another example ：

%  Generate 18 One color 
cList=lines(18);

x=0:.1:4*pi;
hold on
%  Circular drawing 
for i=1:18
    plot(x,sin(x+i*.1).*0.9^i,'Color',cList(i,:),'LineWidth',1.5)
end

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4: Batch notes

The simplest multi line comment is to select multiple lines and click the icon button , The button next to it is to cancel multi line comment ：

Of course, we count cards ： Preset -> Shortcut -> Search for comments , It can also be found that it can be used Ctrl+R Multiline comment , use Ctrl+T uncomment ：

Of course %{ And %} It is also a good method for multi line annotation ：

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5: A few codes appear Chinese garbled

There are many possible reasons for Chinese garbled code , Sorting out an article to deal with all the situations is also very troublesome , Here is a general solution , Is that there will be garbled code m The file suffix consists of .m Change it to .txt Then copy all the contents to the new m File can .

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6: Real root

matlab Use ^ perhaps power To find the odd root of a negative number , The default is virtual root , Realistic roots can be used nthroot function ：

r1=(-3)^(1/3)
r2=power(-3,1/3)

r3=nthroot(-3,3)

r1 =0.7211 + 1.2490i
r2 =0.7211 + 1.2490i
r3=-1.4422

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7: Show only part of the legend

Name each drawing object and treat it as legend The first parameter of the function is ok , for instance ：

x=0:.2:4*pi;
%  Draw some pictures casually 
hold on;grid on
p1=plot(x,sin(x),'-.','LineWidth',2);
p2=plot(x,sin(0.5.*x),'--','LineWidth',2);
p3=plot(x,sin(x).^2,':','LineWidth',2);
%  to 1、3 Image as legend 
legend([p1,p3],{
    'sin(x)','sin^2(x)'})

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8: Generate latex And mathml The formula

Here is an example directly on the official website ：

latex Formula generation

syms x
S = [sym(1)/3 x; exp(x) x^2]

$$S=\left(\begin{array}{cc}\frac{1}{3}& x\\ {\mathrm{e}}^x& x^2\end{array}\right)$$

chr = latex(S)

Running results ：

chr = 
'\left(\begin{array}{cc} \frac{1}{3} & x\\ {\mathrm{e}}^x & x^2 \end{array}\right)'

MathML Formula generation

You can try directly MathML Formula copied to non WPS Of word file , Formulas will be generated directly , however MATLAB For simple formulas , It generates MathML Can be directly in word Generate formula , Don't expect anything complicated ...

syms x
f = 1/exp(x^2);
chr=mathml(f)

Running results ：

chr =

    '<math xmlns='http://www.w3.org/1998/Math/MathML' display='block'>
       <msup>
         <mo>&ee;</mo>
         <mrow>
           <mo>-</mo>
           <msup>
             <mi>x</mi>
             <mn>2</mn>
           </msup>
         </mrow>
       </msup>
     </math>
     '