print "The best conservation laws are hyperbolic!"

from IPython.core.display import HTML
css_file = './custom.css'
HTML(open(css_file, "r").read())

from math import sqrt
print sqrt(2)

import math
print math.sqrt(2)

math.

math.atan2?

x = [1,2,3,4]

print x[0]

print x[1:3]

y = range(1,5)
print y

for i in range(5):
    print i
    print 'in the loop'
    
print 'finished'

for i in range(5):
    print i
    for j in range(2):
        print 'in the inner loop'
    
print 'finished'

def square(x):
    return x**2

print square(5)

import numpy as np

x = np.linspace(0, 1, 5)
print x

y = np.arange(0, 1, 0.2)
print y

print x+y

print x*y

A = np.array([[1,2,3],[4,5,6],[7,8,9]])
print A

print A[0,0]

print A[1:3,0:2]

print A[:,1:]

print A[-1,:]



%matplotlib inline
import matplotlib.pyplot as plt

x=np.linspace(0,4,1000)
f=np.sin(np.exp(x))
plt.plot(x,f)

N = 1000000
a = np.random.rand(N)
b = np.zeros(N-1)

%%timeit
for i in range(len(b)):
    b[i] = a[i+1]-a[i]

%%timeit
b = a[1:]-a[:-1]

print 1/2
print 1.0/2.0