%for_example：Analysis of Phase Portrait Toolbox
%--------------------Copyright Jianli.Panlin-----------------------%
clear
%绘制零斜线
f1=sym('x - y - x*(x^2 + y^2)');
f2=sym('x + y - y*(x^2 + y^2)');
deplot(f1,f2)

%绘制方向
[x,y] =dedata(2,30);
dx=x - y - x.*(x.^2 + y.^2);
dy= x + y - y.*(x.^2 + y.^2);
phase(x,y,dx,dy)

%绘制轨迹
dx=@(t,x)[x(1)-x(2)-x(1)*(x(1)^2+x(2)^2)
               x(1)+x(2)-x(2)*(x(1)^2+x(2)^2)];
t0=0:0.1:50;
x0=[1.5,1.5;-1.5,1.5];
detool(dx,t0,x0)