#!/usr/bin/env python
# coding: utf-8

# ## Plotting options 

# In[1]:


import numpy as np
import matplotlib.pyplot as plt
get_ipython().run_line_magic('matplotlib', 'inline')
import matplotlib as mpl
import sys
label_size = 18
mpl.rcParams['xtick.labelsize'] = label_size 
mpl.rcParams['ytick.labelsize'] = label_size 
from matplotlib import rc
rc('font',**{'family':'sans-serif','sans-serif':['Helvetica']})
## for Palatino and other serif fonts use:
#rc('font',**{'family':'serif','serif':['Palatino']})
rc('text', usetex=True)


# Sea $f(x,y) = x^4 + y^4 -4xy +1$.  Realizar la gráfica de esta función.

# ### Domain

# In[2]:


xlist = np.linspace(-2.2, 2.2, 1000)
ylist = np.linspace(-2.2, 2.2, 1000)
X, Y = np.meshgrid(xlist,ylist)


# ### Function

# In[3]:


Z = X**4 + Y**4 - 4*X*Y + 1


# ### Contour plot 

# In[4]:


plt.figure(figsize=(8,4))
levels = np.arange(0, 50, .5)
plt.contour(X,Y,Z, levels, cmap = 'viridis')
cbar = plt.colorbar()
cbar.ax.tick_params(labelsize = 16)
cbar.outline.set_visible(False)
plt.axis('on')
plt.xlabel('$x$', fontsize = 22)
plt.ylabel('$y$', fontsize = 22)
plt.savefig('basic2D_Ej3C' + '.png', format='png', dpi= 150, bbox_inches='tight');
plt.show()


# ### Packages, version control

# In[2]:


print(f"Python version: {sys.version}")
print(" ")
print("numpy == ", np.__version__)
print("matplotlib == ", mpl.__version__)