#!/usr/bin/env python

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# Authors: Caleb Voss, Wilson Beebe

import matplotlib.pyplot as plt
from pylab import *
from matplotlib import cm

def makeVectorField(f, xmin, xmax, ymin, ymax, step):
    X,Y = meshgrid(arange(xmin,xmax,step),arange(ymin,ymax,step))
    U,V = zip(*map(lambda xx: f(*xx), zip(X,Y)))
    Q = quiver( X, Y, U, V, units='width')
    quiverkey(Q, 0, 0, 4, '', coordinates='figure', labelpos='W')

fig = plt.figure()
ax = fig.gca(aspect='equal')
x = np.loadtxt("vfrrt-nonconservative.path")
makeVectorField(lambda x,y: (y/sqrt(x*x+y*y),-x/sqrt(x*x+y*y)), -6, 6, -6, 6, 0.5)
ax.plot(x[:,0], x[:,1])
plt.show()
