#!/usr/bin/python
# -*- coding: utf8 -*-

import matplotlib.pyplot as plt
import matplotlib as mpl
import numpy as np
from math import *

code_website = 'http://commons.wikimedia.org/wiki/User:Geek3/mplwp'
try:
    import mplwp
except ImportError, er:
    print 'ImportError:', er
    print 'You need to download mplwp.py from', code_website
    exit(1)

name = 'mplwp_cuberoot_negative.svg'
fig = mplwp.fig_standard(mpl)

xlim = -5,5; fig.gca().set_xlim(xlim)
ylim = -2,2; fig.gca().set_ylim(ylim)
fig.gca().xaxis.set_major_locator(mpl.ticker.MultipleLocator(1))
mplwp.mark_axeszero(fig.gca())

f = lambda x: copysign(fabs(x)**(1./3.), x)
x = np.linspace(xlim[0], xlim[1], 5001)
y = [f(xx) for xx in x]
plt.plot(x, y, label='$\sqrt[3]{x}$')

plt.legend(loc='upper left')
    
plt.savefig(name)
mplwp.postprocess(name)