# forced van der Pol
x'=y
y'=-x+y*(1-x^2)+a*u
u'=u*(1-u^2-v^2)-w*v
v'=v*(1-u^2-v^2)+w*u
init u=1
par w=1,a=1
@ total=6.28,dt=.02
@ dsmax=.1
done