教程们emuch常用m作图命令

1、常用作图命令1.概率统计作图1.1 绘出正态分布的密度函数曲线正态分布密度曲线0.40.350.3N(0,2)0.250.20.150.1N(0,1)0.050-5-4-3-2-1012345x=-5:0.1:5;y=normpdf(x,0,1); z=normpdf(x,0,2);plot(x,y,x,z)gtext(N(0,1)gtext(N(0,2)title(正态分布密度曲线)1.2 绘出 t-分布的密度函数曲线，并与标准正态密度曲线比较0.4t分布标准正态密度0.350.30.250.20.150.10.050-5-4-3-2-101x2345x=-5:0.1:5;y=tpdf(x,

2、30); z=normpdf(x,0,1); plot(x,y,k:,x,z,k-) xlabel(itx);ylabel(概率密度itp)legend(t 分布, 标准正态密度) difference=tpdf(x,30)-normpdf(x,0,1)1.3 绘制开方分布密度函数在 n 分别等于 1、5、15 的图0.2x=0:1:30;y1=chi2pdf(x,1); plot(x,y1,:)hold on y2=chi2pdf(x,5);plot(x,y2,+)y3=chi2pdf(x,15);plot(x,y3,O)Axis(0,30,0,0.2)0.180.160.140.120.1

3、0.080.060.040.020051015202530概率密度 p1.4 计算自由度是 50,10 的 F-分布的 0.9 的分位数，并给出概率与分位数关系的图形x=finv(0.9,50,10)p=fcdf(x,50,10) t=0:0.1:4;y=fpdf(x,50,10);z=fpdf(t,50,10); plot(t,z,x,x,0,y) text(x,0,2.1171)gtext(p=0.9)x = 2.1171p = 0.90000.20.1title(概率与分位数的关系)000.51.5 经验累布函数图形X=normrnd (0,1,50,1);h,stats=cdfplot

4、(X)0.80.70.60.50.40.30.20.1Em1Empirical Theoreticaly = evrnd(0,3,100,1); cdfplot(y)hold onx = -20:0.1:10;f = evcdf(x,0,3);plot(x,f,m) legend(Empirical,Theoretical,Location,NW)0.90.80.70.60.50.40.30.20.1F(x)F(x)1.6 绘制正态分布概率图形Normal Probability Plot0.990.980.950.900.750.500.250.100.050.020.01-2.5-2-1.

5、5-1-0.5Data00.511.5X=normrnd(0,1,50,1);normplot(X)1.7 绘制尔(Weibull)概率图形%绘制尔(Weibull)概率图形的目的是用图解法估计来自尔分布的数据X，如果X是%尔分布数据，其图形是直线的，否则图形中可能产生弯曲。Weibull Probability Plot0.990.960.900.75r = weibrnd(1.2,1.5,50,1);weibplot(r)0.500.250.100.050.020.01-101010Data1.8 样本数据的盒图%boxplot(X) %产生矩阵X的每一列的盒图和“须”图，“须”是从盒的尾

6、部延伸出来，并表示盒外数据长度的线，如果“须”的外面没有数据，则在“须”的底部有一个点。x1 = normrnd(5,1,100,1); x2 = normrnd(6,1,100,1); x = x1 x2;boxplot(x,1,g+,1,0)87654312Column NumberProbabilityProbabilityValues1.9 样本的概率图形Probability Between Limits = 0.867830.35data=normrnd (0,1,30,2); p=capaplot(data,-2,2)p =0.91990.30.250.20.150.10.051

7、.10附加有正态密度曲线的直方图25r = normrnd (10,1,100,1);histfit(r)20151051.11在指定的界线之间画正态密度曲线格式 p = normspec(specs,mu,sigma) %specs 指定界线，mu,sigma 为正态分布的参数p为样本落在上、下界之间的概率Probability Greater than Lower Bound is 0.884930.350.30.250.20.150.10.05078910111213141516Critical Valuenormspec(10 Inf,11.5,1.25)1.12 二项分布的函数图De

8、nsityp = 0.2; % Probability of success for each trial n = 10; % Number of trialsk = 0 n; % Outcomesm = binopdf(k,n,p); % Probability mass vector bar(k,m) % Visualize the probability distribution set(get(gca,Children),FaceColor,.8 .8 1)grid on0.350.30.250.20.150.10.051.13指数分布函数图2lambda = 2; % Failure

9、 rate t = 0:0.01:3; % Outcomesf = exppdf(t,1/lambda); % Probability density vector plot(t,f) % Visualize the probability distributiongrid on1.81.61.41.210.80.60.40.2000.511.522.531.14 ksdensity 概率密度估计函数cars = load(carsmall,MPG,Origin);Density estimate for MPG0.06MPG = cars.MPG;f,x,u = ksdensity(MPG)

10、; plot(x,f)title(Density estimate for MPG) hold onf,x = ksdensity(MPG,width,u/3); plot(x,f,r);f,x = ksdensity(MPG,width,u*3); plot(x,f,g);legend(default width,1/3 default,3*default)hold offdefault width 1/3 default 3*default0.050.040.030.020.010-40-200204060801000.045normal epanech box0.040.0350.030

11、.0250.020.0150.010.005hname = normal epanechnikov box triangle; colors = r b g m;for j=1:4f,x = ksdensity(MPG,kernel,hnamej); plot(x,f,colorsj);hold on;end legend(hname:); hold off2.常用作图函数2.1 普通双函数图Two Y Axes33t = 0:pi/20:2*pi; y = exp(sin(t);plotyy(t,y,t,y,plot,stem) xlabel(X Axis) ylabel(Plot Y Ax

12、is)title(Two Y Axes)2 52 5221 51 5110 50 50001234567X AxisPlot Y Axis2.2 多数据集在同一图中1sin(x) sin(x-.25)sin(x-.5)0.80.60.40.20-0.2-0.4-0.6-0.8-101234567x = 0:pi/100:2*pi; y = sin(x);y2 = sin(x-.25);y3 = sin(x-.5);plot(x,y,x,y2,x,y3) legend(sin(x),sin(x-.25),sin(x-.5)2.3 在原图上继续作图 hold onx,y,z = peaks;pco

13、lor(x,y,z) shading interp hold oncontour(x,y,z,20,k)hold off2.4 同一图中作多个图110.80.80.60.60.40.20.40-0.2-0.4-0.6-0.8-clearx= 0.1:0.1:4*pi; %生成向量 x。生成 y 1 值y1=sin(x);y2=sin(x) ./x; figure;% 生成 y 2 值。% 创建一个新窗口。subplot(1, 2, 1); % 定义第一个子图区域。plot(x, y1);% 用实线画曲线。subplot(1, 2, 2); % 定义第二个子图区域。plot(x,y2,*);%

14、用*号画曲线DefaultX scale manipulated10108866442202468137Y scale manipulatedBoth scales manipulated99662202468137clear;x = 1 3 7;y = 6 9 2;s1 = subplot(2,2,1); plot(x,y);grid;title(Default);s2 = subplot(2,2,2); plot(x,y);set(s2,XTick,x); 改变X 轴标记set(s2,XGrid,on); 画X 轴的格栅线title(X scale manipulated);s3 = su

15、bplot(2,2,3); plot(x,y);set(s3,YTick,2,6,9); 改变 y 轴标记set(s3,YGrid,on); 画y 轴的格栅线set(s3,GridLineStyle,-.); 使用虚线格栅title(Y scale manipulated);s4 = subplot(2,2,4); plot(x,y);set(s4,XTick,x); 改变 xy 轴标记set(s4,YTick,2 6 9);grid; 画 xy 轴的格栅线title(Both scales manipulated);clf reset%Clearing theFigure for a New

16、 Plot t = 0:pi/10:2*pi;X,Y,Z = cylinder(4*cos(t);subplot(2,2,1); mesh(X)subplot(2,2,2); mesh(Y)subplot(2,2,3); mesh(Z)subplot(2,2,4); mesh(X,Y,Z)2.5的显示(字符参照 Latex 标准)Graph of the sine function10.80.60.40.20-0.2Note the odd symmetry.-0.4-0.6-0.8-1-3-2-10-p t p123t = -pi:pi/100:pi; y = sin(t);plot(t,y

17、)axis(-pi pi -1 1)xlabel(-pi leq itt leq pi) ylabel(sin(t)title(Graph of the sine function)text(1,-1/3,itNote the odd symmetry.)2.6多元变量作图X,Y = meshgrid(-8:.5:8); R = sqrt(X.2 + Y.2) + eps; Z = sin(R)./R;mesh(X,Y,Z,EdgeColor,black) %使用 mesh(X,Y,Z)采用默认颜色；sin(t)2.7 定义函数作图-10-15-2function myfunc(x)% x =

18、 -10:.005:40; Heres a value you can use for xy = 1.5*cos(x) + 6*exp(-.1*x) + exp(.07*x).*sin(3*x); ym = mean(y);hfig = figure(Name,Function and Mean,. Pointer,fullcrosshair);hax = axes(Parent,hfig); plot(hax,x,y)hold onplot(hax,min(x) max(x),ym ym,Color,red) hold offylab = get(hax,YTick); set(hax,YT

19、ick,sort(ylab ym)title (y = 1.5cos(x) + 6e-0.1x + e0.07xsin(3x)xlabel(X Axis); ylabel(Y Axis)2.8 使用 fplot 作图函数80604020000.550-5-6-4subplot(2,2,1);fplot(humps,0 1) subplot(2,2,2);fplot(abs(exp(-j*x*(0:9)*ones(10,1),0 2*pi)subplot(2,1,2);fplot(tan(x),sin(x),cos(x),2*pi*-1 1 -1 1)%后面参数表示x,y 上下界;2.9 给当前

20、图形加一条参考线y = 3.2 2.6 3.1 3.4 2.4 2.9 3.0 3.3 3.2 2.12.6;plot(y,+) refline(0,3)2.5212342.10 在当前图形中加入一条多项式曲线格式 h = refcurve(p) %在图中加入一条多项式曲线，h 为曲线的环柄，p p=p1,p2, p3,pn，其中p1 为最高幂项系数h = 85 162 230 289 339 381 413 437 452 458 456 440 400 356;plot(h,+)refcurve(-4.9 100 0)为多项式系数向量，500450400350300250200150100

21、503.常用作图工具3.1 plottools在输入变量后，如：x = -1:.1:1; % Define the range of xy = x.3; % Raise each element in x to the third power可输入 plottools 调用相应的作图工具;使用非常方便4.特殊图形作图4.1 画极坐标图21024t = 0:.01:2*pi;polar(t,sin(3*t).*cos(2*t),-r)4.2 bar 图543210-3-2-1x = -2.9:0.2:2.9;bar(x,exp(x.*sin(x) colormap gray.3 barh 图32

22、1X = 1:.5:5;Y = exp(X).*sin(X);barh(Y,stack)4.4 compass 图Z = magic(20).*randn(20);compass(Z)150180210240Z = eig(randn(20,20);compass(Z)1201501802102404.5 comet 图t = 0:.01:2*pi;x = exp(sin(2*t).*(cos(t).2/3); y = t.*(sin(t).2);comet(x,y)hold on4.6 errorbar 图121086420-2-4-0.500.511.522.533.5X = 0:pi/2

23、0:pi;Y = exp(X).*sin(X);E = std(Y)*ones(size(X); errorbar(X,Y,E)4.7 feather 图43210-1-2-3-40246810 12 1416 1820th = (-90:10:90)*pi/180;r = 4*ones(size(th); u,v = pol2cart(th,r); feather(u,v);4.8 hist 图%功能 二维条形直方图，可以显示出数据的分配情形。x = -5:0.1:5;y = randn(1000,1); hist(y,x)20100-6-4-24.9 rose 图theta = 3*pi*

24、randn(1,30);rose(theta)4.10 s3x = 0:.25:10;stairs(x,exp(sin(x.2)2.524.11 stem 图x = linspace(0,2,10); stem(exp(-x.2),fill,-.)1.510.510.900.80.70.60.50.40.30.20.10124.12 pie 图x = 1 3 0.5 2.5 2;explode = 0 1 0 0 0; pie(x,explode)形作图5.5.1 pie3 图x = 1 3 0.5 2.5 2;explode = 0 1 0 0 0; pie3(x,explode) colo

25、rmap hsv22%11%28%5.2 sphere 图33%6%X,Y,Z=sphere; mesh(X,Y,Z)hidden off5.3 基本t=0:pi/50:10*pi; plot3(sin(t),cos(t),t); axis square;grid on;40302010010.510.500-0.5-0.5-1 -1X,Y=meshgrid(-2:0.1:2); Z=X.*exp(-X.2-Y.2);plot3(X,Y,Z);grid on;sin(x),sin(2x),sin(3x)x=linspace(0,3*pi); % x-axis data z1=sin(x); %

26、 plot in x-z plane z2=sin(2*x);z3=sin(3*x);y1=zeros(size(x); % spread out along y-axis y3=zeros(size(x); % by giving each diffent y-axis valuesy2=y3/2; plot3(x,y1,z1,x,y2,z2,x,y3,z3);grid,xlabel(x-axis),ylabel(y-axis),zlabel(z-axis);title(sin(x),sin(2x),sin(3x);10.50-0.5-110.55.4 绘制复数图实例：如何在极坐标表下绘制复

27、数函数 z、z2、z3 和 4 z4 -1 的曲面图形?z=cplxgrid(20);%准备网格,使用 cplxgrid 函数创建一个 21*41 的复数网格矩阵;subplot(2,2,1);z-axiscplxmap(z,z);title(线性运算);xlabel(实轴);ylabel(虚轴);zlabel(函数值);subplot(2,2,2);cplxmap(z,z.2);title(平方运算);subplot(2,2,3);cplxmap(z,z.3);title(立方运算);subplot(2,2,4); cplxmap(z,(z.4-1).(1/4); title(复杂运算);xlabel(实轴);ylabel(虚轴);zlabel(函数值);6.插值拟合作图6.1 polyfit/polyval2x = (0: 0.1: 5);y = erf(x);p = polyfit(x,y,6) f = polyval(p,x); plot(x,y,o,x,f,-)axis(0 5 0 2)1.81.61.41.210.80.60.40.2000.511.522.53