[x,y,z]=peaks;
surfc(x,y,z);
z>=0;
axis([-inf inf -inf inf -inf inf]);
mu = [0, 0];
sigma = [4 1;1 9];
mu1 = mu(1);
mu2 = mu(2);
si1 = sqrt(sigma(1,1));
si2 = sqrt(sigma(2,2));
d1 = linspace(mu1-3*si1, mu1+3*si1,30);
d2 = linspace(mu2-3*si2, mu2+3*si2,30);
[X,Y] = meshgrid(d1,d2);
xy = [X(:) Y(:)];
p = mvnpdf(xy,mu,sigma);
p = reshape(p,size(X));
[X,Y,p]=peaks;
surfc(X,Y,p)
axis([0 5 -inf inf -inf inf]);
theta=0:0.1:2*pi;
phi=theta';
x=cos(phi)*cos(theta);
y=cos(phi)*sin(theta);
z=sin(phi)*ones(size(theta));
mesh(x,y,z);
shading interp
ezsurf('8*tan(u)*cos(v)','8.*tan(u)*sin(v)','2.*sec(u)',[-pi./2,3*pi./2,0,2*pi])
axis equal
grid on
axis square
xlabel('x轴');ylabel('y轴');zlabel('z轴');
title('双叶双曲面')
[fia,theta]=meshgrid([linspace(0,pi,100),pi]);
x=sin(theta).*cos(fia);
y=sin(theta).*sin(fia);
z=cos(theta);
surf(x,y,z)
shading interp
fxy=@(b,x1,x2)b(6)/(2*pi*b(3)*b(4)*sqrt(1-b(5)^2))*exp(-1/(2*(1-b(5)^2))*((x1-b(1)).^2/b(3)^2-2*b(5)*(x1-b(1)).*(x2-b(2))/(b(3)*b(4))+(x2-b(2)).^2/b(4)^2))+b(12)/(2*pi*b(9)*b(10)*sqrt(1-b(11)^2))*exp(-1/(2*(1-b(11)^2))*((x1-b(7)).^2/b(9)^2-2*b(11)*(x1-b(7)).*(x2-b(8))/(b(9)*b(10))+(x2-b(8)).^2/b(10)^2));
[x y]=meshgrid(0:.25:20);
b=[5,15,2,2,.7,15,15,10,2,3,.3,30]; %形状参数由此调节,-1<b(5),b(11)<1
figure(1),clf
z=fxy(b,x,y);
mesh(x,y,z)
pause(2)
surf(x,y,z)
pause(2)
shading interp
alpha(.9)
评论0