""" From "A SURVEY OF COMPUTATIONAL PHYSICS", Python eBook Version
   by RH Landau, MJ Paez, and CC Bordeianu
   Copyright Princeton University Press, Princeton, 2012; Book  Copyright R Landau, 
   Oregon State Unv, MJ Paez, Univ Antioquia, C Bordeianu, Univ Bucharest, 2012.
   Support by National Science Foundation , Oregon State Univ, Microsoft Corp"""  

# LyapLog.py:                Lyapunov coef for logistic map

from pylab import *

m_min = 3.5;        m_max = 3.65;        step = 0.002
#m_min = 3.5;        m_max = 4.0;        step = 0.005
#m_min = 3.5;        m_max = 3.75;        step = 0.0025
#m_min = 3.82;        m_max = 3.86;        step = 0.00025 # window

mm = arange(m_min, m_max, step)
m0 = 0
ssuma = zeros(size(mm))

for m in mm:
    y = 0.5
    suma = 0.0
    for i in range(1, 400, 1):   y = m*y*(1 - y)        # Skip transients
    for i in range(401, 600, 1):
        y = m*y*(1 - y)
        plot(m,y,".b",markersize=1)  # seepd up, no repeats?
        suma = suma  +  log(abs(m*(1. - 2.*y) ))               # Lyapunov
#    print m0,suma
    ssuma[m0] = suma/200
    m0 += 1

plot(mm, ssuma,"-",markersize = 3,color = "green" ) 

show()