matlab自然对数

x=-3:0.1:3;y=-2:0.1:2;
[x,y]=meshgrid(x,y);
z=(x.^2-2*x).*exp(-x.^2-y.^2-x.*y);
figure
mesh(x,y,z)%网格图
figure
contour(x,y,z)%等高线图