# !/usr/bin/env python
# Diff courbes
#

import matplotlib.pyplot as plt

a=[[0,20],[10,25],[40,50],[70,90],[80,110],[100,150],[120,100]]
b=[[5,15],[15,20],[40,55],[65,100],[90,140],[110,121],[125,100],[140,80]]

ax_l=[0,10,40,70,80,100,120]
ay_l=[20,25,50,90,110,150,100]

bx_l=[5,15,40,65,90,110,125,140]
by_l=[15,20,55,100,140,121,100,80]

cy_l=[]
cx_l=[]

#boucle sur les elements de ax
i=0
for eax in ax_l:
	i=i+1
#	print 'eax=',eax
	ii=0
	t=0
	for ebx in bx_l:
#		print 'ebx=',ebx
		ii=ii+1
		if (ebx > eax):
			k=(by_l[ii-1]-by_l[ii-2])/(bx_l[ii-1]-bx_l[ii-2])
			ba=by_l[ii-2]+k*(eax-bx_l[ii-2])
			if (t == 1):
				cx_l.append(eax)
				cy_l.append((ba+ay_l[i-1])/2)
#				print 'ax=',ax_l[i-1], 'ebx',ebx, 'bx-=',bx_l[ii-2],'bx+=',bx_l[ii-1], 'ii=',ii,'ba=',ba
			break
		else:
			t=1
			

#print 'i=',i,'  ii=',ii	

#Creation de l'image:

plt.plot(ax_l,ay_l)
plt.plot(bx_l,by_l)
plt.plot(cx_l,cy_l,"k--")
plt.grid(True)

plt.show()

# fin du programme