4.数组及运算—2课时.pptVIP

Matlab及其应用;MATLAB 及应用;;数组分类;实例;4.1 数值数组;%This segment demonstrate the creation of 1-D numerical array a=[2 pi/2 sqrt(3) 3+5i] b=0:2:20 c=2:12 d=0:1.5:10 e=linspace(1.1,9.6,12) f=logspace(2,4,11) %This segment demonstrate the access of 1-D numerical array x1=a(3) x2=a(1)/b(3) x3=c([2 4 6]) x4=d(2:6) x5=e(10:-2:1) x6=e(find(e5)) x7=f([1 3 5 7 8 6 4 2]) %This segment demonstrate the assignment of 1-D numerical array x3(2)=0 x4([1 3 5])=[0 0 0] x4([2 4])=0;;%-------Creation of the 2-D array----------- a=3; b=5; c=[1 a a+b*i b;pi sin(pi) b*i i] d=c; e=c(:,1:2)+i*d(1:2,:) narr3; %call script M-file am %-------Access of the 2-D array----------- f=am(2,3) g=am(2:4:16) %按行显，按列存 h=am(:,2) k=am(:) %-------Assignment of the 2-D array----------- am(3,2)=0 am([2 8 12])=[0 0 0] am(:)=0;;;数组运算与矩阵运算是完全不同的概念，数组运算是MATLAB特有的便于计算和表示的算法，而矩阵运算是有严格的数学定义的。;;%-----------methods of diag----------- a=diag([2 3 4 5]) b=diag([2 3],-1) x=diag(b) u=diag(b,-1) %-----------methods of eye------- c=eye(3) d=eye(3,2) e=eye(size(a)) %-----------methods of magic--- f=magic(3) %-----------methods of ones----- g=ones(3) h=ones(2,3) k=ones(size(a)) %-----------methods of zeros------ l=zeros(3) m=zeros(2,3) n=zeros(size(a)) ;;4.1.7 数组操作函数（narr5.m）;a=-4:4 b=reshape(a,3,3) c=b+i*b d=b e=c f=flipud(b) %flip up and down g=fliplr(b) %flip left and right h=cat(1,f,g) %cat the f and g in the 1st dimension,Column k=cat(2,f,g) %cat the f and g in the 2nd dimension,Row l=cat(3,f,g) %cat the f and g in the 3rd dimension %K = kron(X,Y) returns the Kronecker tensor product of X and Y %If X is 2-by-3, then kron(X,Y) is %[ X(1,1)*Y X(1,2)*Y X(1,3)*Y % X(2,1)*Y X(2,2)*Y X(2,3)*Y ] m=kron(d,g) n=kron(g,d) %B = repmat(A,m,n) creates a large matrix B consisting of an %m-by-n tiling of copies of A p=repmat(b,2,2);;t=-2*pi:pi/10:2*pi; y=sin(t)./t; %dot divide array operation, view the creation of NaN at t=0 z=(t==0) %view the creation of logical arra