teleportation_circuit.py

# -*- coding: utf-8 -*-
"""
Created on Sat Feb  1 10:14:27 2020

@collaborators: Hantoa, Derrick, Malvika, & Sergio

Quantum Teleportation from https://qiskit.org/textbook/ch-algorithms/teleportation.html
"""

import numpy as np
from qiskit import QuantumRegister, ClassicalRegister
from qiskit import(
  QuantumCircuit,
  execute,
  Aer,
  IBMQ)
from qiskit.providers.ibmq import least_busy
from qiskit.visualization import plot_histogram
import getpass
import matplotlib.pyplot as plt

# Create a Quantum Circuit acting on the q register
q = QuantumRegister(3, 'q')
c = ClassicalRegister(3, 'c')
circuit = QuantumCircuit(q, c)

# curQ is an int that is keeps track of which players qubit to modify 
# and is 0 if it's player 1's turn to send the state 2 if it's player 2's turn.

scores = [0,0]

def getUserInput(curQ):
    valid = "xyzht"
 #   print("Enter transformations to apply from (x,y,z,h,t)")
    
    input_str = ""
    while True:
        check = True
        choice = getpass.getpass("Enter transformations to apply from (x,y,z,h,t): ") 
        if len(choice) > 5 or len(choice) == 0 : check = False
        for c in choice:
          if c not in valid:
            check = False
            break

        if check:
            input_str = choice
            break
        else:
            print("Enter a valid transformation")
    
    #curQ>>1 gives which players turn it is (0/1)
    scores[curQ>>1] += len(input_str)
    return input_str 

def player_operation(input_string, q, circuit, dagger):
    apply_gate = {
                    'x': circuit.x,
                    'y': circuit.y,
                    'z': circuit.z,
                    'h': circuit.h,                    
                    't': circuit.t,                    
    }
    if dagger: apply_gate['t'] = circuit.tdg
    
    if dagger:
        [apply_gate[gate](q) for gate in input_string]
    else:
        [apply_gate[gate](q) for gate in input_string[::-1]]

# addTeleport adds a new teleportation to the circuit
def addTeleport(curQ, nxtQ):
    
    # Design phi
    #player_operation(getUserInput(), curQ, circuit, dagger=False)
    circuit.barrier()
    
    # Design beta_00
    circuit.h(1)
    circuit.cx(1, nxtQ)
    circuit.barrier()
    
    # First measurement on sender information
    circuit.cx(curQ, 1)
    circuit.h(curQ)
    #circuit.measure(curQ, curQ)
    #circuit.measure(1, 1)
    
    # After sending classical information
    circuit.cx(1, nxtQ)
    circuit.cz(curQ, nxtQ)
    circuit.barrier()
    circuit.h(curQ)
    circuit.h(1)


# endgame ends the game, does measurements, and draws the circuit.
def endgame(curQ, desired_device, measured=False):
    # Apply transformation in reverse if we only care about input (currently 0?)
    #player_operation(input_string, q[2], circuit, dagger=True)
    
    # Measure q[2]
    circuit.measure(curQ, curQ)
    
    # Define device
    if desired_device == 'sim':
        device = Aer.get_backend('qasm_simulator')
        shots = 1023
    elif desired_device == 'qc':
        print("Connecting to quantum computer...")
        IBMQ.save_account('292ebd1c42498b47d4d3c1076b3afa016395350f214fcc5d598241639624171f63a78ddde5ae15d23445c9627c7da5e8883c42d020c4cf84451dc39e36a6c6cb', overwrite=True)
        provider = IBMQ.load_account()
        device = least_busy(provider.backends(simulator=False))
        shots = 127
        print("Making quantum computations...")
    
    # Execute the circuit on the qasm simulator or device
    job = execute(circuit, backend=device, shots=shots)
    
    # Grab results from the job
    result = job.result()
    
    # Returns counts
    counts = result.get_counts(circuit)
    print("\nTotal count are:",counts)
    
    
    if(measured):
      player = (curQ>>1)+1
      measurementEnd(counts, player, shots>>1)

    print("Number of gates applied by each player ",scores)
    
    circuit.draw(output='mpl').show()
    plt.show()

def measurementEnd(counts, player, half):
    winCount = 0
    for x in range(4,8):
      winState = bin(x)[2::]
      if (player == 1):
        winState = winState[::-1]
      if(winState in counts):
        winCount =  winCount + counts[winState]
   
    if(winCount > half):
      print("More than half of the measurements gave 1!")
      print("Player " + str(player) + " wins")
    else:
      print("Less than half of the measurements gave 1 :(")
      print("Player " + str(((player-1)^1)+1) + " wins")
# Draw the circuit in Console separately!!!
#circuit.draw(output='mpl')
#plot_histogram(counts)