# -*- coding: utf-8 -*-
"""
Created on Wed Dec 03 14:18:21 2014

@author: grivet

Exercice 1-9 : tracé d'équipotentielles pour deux charges
éléctriques positives.
Syntaxe simple.

"""
from pylab import *

def V(x,y,r):
    return ((x-r[0])**2+(y-r[1])**2)**(-1)

a = 1.5
points = [[-a,0],[a,0]]

def potentiel(x,y):
    return V(x,y,points[0])+V(x,y,points[1])

n = 256
x = linspace(-5,5,n)
y = linspace(-5,5,n)
X,Y = meshgrid(x,y)
niv = [0.1,0.5,0.86,2.0,5.0,10.0,20.0]
cs = contour(X,Y,potentiel(X,Y),niv)
clabel(cs)
show()