[pstricks] pst-ode

[cyrille piatecki]

I would like to know if

  pst-ode can plot a phase diagram (\dot{x}, x), with arrow showing the 
direction of evolution ? If not is there some one who can show how to do 
it  for an equation of the type $\dot{x}=x(1-x) (x - a)$ for $a \in ]0, 1[

Thanks

Cyrille Piatecki