#  Code for Monte Carlo class, Jonathan Goodman

#  http://www.math.nyu.edu/faculty/goodman/teaching/MonteCarlo20/
#  ObjectBinding.py

#  The author gives permission for anyone to use this publicly posted 
#  code for any purpose.  The code was written for teaching, not research
#  or commercial use.  It has not been tested thoroughly and probably has
#  serious bugs.  Results may be inaccurate, incorrect, or just wrong.

# illustrate objects and binding in Python

import numpy as np           #  to illustrate mutable objects

print("\n   Illustrate binding and mutation in Python\n")

x = np.zeros(3)            # numpy array is mutable
z = np.zeros(3)            # identical but not the same
y = x                      # new name bound to the same object

print("(x is y) is " + str(x is y))     #  "is": bound to the same object?
print("(x is z) is " + str(x is z))
print("(x == z) is " + str(x == z))     #  "==": have the same value, element by element

print("(x[1] is x[2]) is " + str(x[1] is x[2]))     #  different objects ...
print("(x[1] == x[2]) is " + str(x[1] == x[2]))     #  ... can have the same value

x[0] = np.pi
OutFormat = "x[0] is {x0:6.4f},  y[0] is {y0:6.4f},  z[0] is {z0:6.4f}"
Outline   = OutFormat.format(x0 = x[0], y0 = y[0], z0 = z[0])
print(Outline)

u = x.copy()
x[1] = np.e
u[0] = np.sqrt(2)

OutFormat = "x is [{x0:6.4f}, {x1:6.4f}, {x2:6.4f}]"
Outline   = OutFormat.format(x0 = x[0], x1 = x[1], x2 = x[2])
print(Outline)
OutFormat = "u is [{u0:6.4f}, {u1:6.4f}, {u2:6.4f}]"
Outline   = OutFormat.format(u0 = u[0], u1 = u[1], u2 = u[2])
print(Outline)