#!/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_roots2to4.svg'
fig = mplwp.fig_standard(mpl)

xlim = -0.25,4.25; fig.gca().set_xlim(xlim)
ylim = -0.25,2.75; fig.gca().set_ylim(ylim)
fig.gca().xaxis.set_major_locator(mpl.ticker.MultipleLocator(0.5))
mplwp.mark_axeszero(fig.gca())

for p in range(2, 4+1):
    f = lambda x: x**(1./p)
    x = np.linspace(0, xlim[1], 10001)
    y = [f(xx) for xx in x]
    if p == 2:
        label = '$\sqrt{x}$'
    else:
        label = '$\sqrt[' + str(p) + ']{x}$'
    plt.plot(x, y, label=label)

plt.legend(loc='upper center', ncol=3).get_frame().set_alpha(0.9)
    
plt.savefig(name)
mplwp.postprocess(name)