# fisher.ode
# traveling waves in fisher's equation
#  u_t = D*u_xx + r*u(1-u)
#
# 0 = D*u'' + cu' + r*u(1-u)
#
f(u)=u*(1-u)
u'=v
v'=-c/D*v-r/D*f(u)
par c=2, D=1, r=1
init u=1
@ xp=u,yp=v,xlo=-.25,xhi=1.25,ylo=-.5,yhi=.5
done