Plotting bifurcation diagram of the following map using pylab
N_{t+1} = N_t e^{r (1-N_t)}

def F(x,r=1): return x*exp(r*(1-x))

def prop(F, N0, N):
  x=zeros(N)
  x[0]=N0
  for i in xrange(1,N):
    x[i]=F(x[i-1])
  return x

L=200

for r in linspace(1,4,300):
  plot(r+zeros(L-50), prop(lambda x: F(x, r), 0.1, L)[50:],'.k', markersize=1)