#!/usr/bin/env python

#-------------
# Load modules
#-------------

import time
from numpy import *

a = linspace(0, 1, 1E+08)  # create some array
t0 = time.clock()
b = 3*a - 1
t1 = time.clock()   # t1-t0 is the CPU time of 3*a-1

for i in xrange(a.size):
    b[i] = 3*a[i] - 1

t2 = time.clock()

b = a
b *= 3
b -= 1

t3 = time.clock()

print 'Computing b= 3*a-1', a.size
print '     Vec: %15.10f sec' % (t1-t0)
print '    Loop: %15.10f sec' % (t2-t1)
print 'In-Place: %15.10f sec' % (t3-t2)