matlab实验：插值与拟合.ppt

* * t=linspace(0,1.5,20); Vx=2*t;Vy=2*t.^2;Vz=6*t.^3-t.^2; x=t.^2;y=(2/3)*t.^3;z=(6/4)*t.^4-(1/3)*t.^3; plot3(x,y,z,r.-,linewidth,1,markersize,10),hold on Vx=gradient(x);Vy=gradient(y);Vz=gradient(z); h=quiver3(x,y,z,Vx,Vy,Vz);set(h,linewidth,1),grid on axis([0 1.5 0 1.5 0 40]) xlabel(x),ylabel(y),zlabel(z) box on, hold off * * * * x0=[0 3 5 7 9 11 12 13 14 15 ]; y0=[0 1.2 1.7 2.0 2.1 2.0 1.8 1.2 1.0 1.6 ]; x=0:0.1:15; y=interp1(x0,y0,x,spline); plot(x0,y0,k+,x,y,r) grid on * * * x=[129 140 103.5 88 185.5 195 105.5 157.5 107.5 77 81 162 162 117.5]; y=[7.5 141.5 23 147 22.5 137.5 85.5 -6.5 -81 3 56.5 -66.5 84 -33.5]; z=[-4 -8 -6 -8 -6 -8 -8 -9 -9 -8 -8 -9 -4 -9]; cx=75:0.5:200; cy=-70:0.5:150; cz=griddata(x,y,z,cx,cy,cubic); meshz(cx,cy,cz),rotate3d xlabel(X),ylabel(Y),zlabel(Z) %pause figure(2),contour(cx,cy,cz,[-5 -5]);grid on, hold on plot(x,y,+) xlabel(X),ylabel(Y) * * x=0:0.1:1; y=[-0.447,1.978,3.28,6.16,7.08,7.34,7.66,9.56,9.48,9.30,11.2]; A=polyfit(x,y,2) z=polyval(A,x); plot(x,y,k+,x,z,r) * x1=3.4:6.7, x2=3.4:2:6.7, x3=2.6:-0.8:0; x=linspace(0,1,5), whos * x=[1 2 3]; y=[2 2 2]; a=10; a*x, x+a, x+y, x-y, a^2 * x.*y ,x./y,x.\y,x.^5, 2.^x,x.^y * x=linspace(0,4*pi,100); y=sin(x); y1=sin(x).^2; y2=exp(-x).*sin(x); plot(x,y,-,x,y1,-,x,y2,.-) * A=[1 2 3 4; 5 6 7 8; 9 10 11 12] B=[-1.3,sqrt(3);(1+2)*4/5,sin(5);exp(2),6] * A, A_trans=A’ --------------------- H=[1 2 3 ; 2 1 0 ; 1 2 3 ], K=[1 2 3 ; 2 1 0 ; 2 3 1], h_det=det(H),k_det=det(K), H_inv=inv(H),K_inv=K^-1 ---------------------- * * A=[3 0 1; 1 1 0;0 1 4]; B=inv(A-2*eye(3))*A, B=(A-2*eye(3))\A * A=[1 0 1 1 2;0 1 -1 2 3;3 0 5 1 0;2 3 1 2 1], vr=[1,3];vc=[1,3];A1=A(vr,vc) * A11=A(1:2,1:2),A12=A(1:2,3:5), A21=A(3:4,1:2),A22=A(3:4,3:5) B=[A11 A12;A21 A22] * A=[1 0 1 1 2;0 1 -1 2 3;3 0 5 1 0;2 3 1 2 1]; A(1,:)=[0 0 0 0 0]; A --------------------------------------- A([1,3],:)=[ ] * * * * * A=rand(3,6), Asort=sort(A), Amax=max(A), Asum=sum(A) * * * clf, x=linspace(0,8*pi,100); y1=sin(x+cos