# a heteroclinic orbit
# unstable at u=1, stable at u=0
f(u,up)=up
g(u,up)=-c*up-u*(1-u)*(u-a)
u'=up*per
up'=(-c*up-u*(1-u)*(u-a))*per
uleft'=0
upleft'=0
uright'=0
upright'=0
per'=0
c'=0
# unstable manifold
b (u-uleft)*lamp-(up-upleft)
b (u'-uright)*lamn-(up'-upright)
b sqrt((u-uleft)^2+(up-upleft)^2)-eps
b sqrt((u'-uright)^2+(up'-upright)^2)-eps
b f(uleft,upleft)
b g(uleft,upleft)
b f(uright,upright)
b g(uright,upright) 
lamn=(c-sqrt(c^2+4*a))/2
lamp=(c+sqrt(c^2+4*(1-a)))/2
par a=.5,eps=.1
init u=.918,up=-.0577,per=6.67,c=0
init uleft=1,upleft=0,uright=0,upright=0
@ total=1.01,dt=.01
done