"""PyWENO smooth reconstruction example."""

import numpy as np
import pyweno.weno

import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt

f = np.cos
F = np.sin

x = np.linspace(0.0, 2*np.pi, 21)
a = (F(x[1:]) - F(x[:-1]))/(x[1]-x[0])
l, s = pyweno.weno.reconstruct(a, 5, 'left', return_smoothness=True)
r    = pyweno.weno.reconstruct(a, 5, 'right')

plt.title('pyweno.weno reconstruction and smoothness indicators')

plt.subplot(2,1,1)

plt.plot(x,   f(x), '-k')
plt.plot(x[:-1], l, 'or')
plt.plot(x[1:],  r, 'ob')

plt.ylabel('f')
plt.xlabel('x')
plt.legend(['actual', 'left', 'right'])

plt.subplot(2,1,2)

c = 0.5*(x[1:] + x[:-1])

plt.plot(c, s[:,0], 'or')
plt.plot(c, s[:,1], 'ok')
plt.plot(c, s[:,2], 'ob')

plt.ylabel('smoothness')
plt.xlabel('x')
plt.legend(['r=0', 'r=1', 'r=2'])

plt.savefig('smooth.png', format='png')